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Putative Sex Differences in Verbal Abilities and Language Cortex: A Critical Review
Abstract
This review brings together evidence from a diverse field of methods for investigating sex differences in language processing. Differences are found in certain language-related deficits, such as stuttering, dyslexia, autism and schizophrenia. Common to these is that language problems may follow from, rather than cause the deficit. Large studies have been conducted on sex differences in verbal abilities within the normal population, and a careful reading of the results suggests that differences in language proficiency do not exist. Early differences in language acquisition show a slight advantage for girls, but this gradually disappears. A difference in language lateralization of brain structure and function in adults has also been suggested, perhaps following size differences in the corpus callosum. Neither of these claims is substantiated by evidence. In addition, overall results from studies on regional grey matter distribution using voxel-based morphometry, indicate no consistent differences between males and females in language-related cortical regions. Language function in Wada tests, aphasia, and in normal ageing also fails to show sex differentiation.
... Language is fundamental of nearly every facet of human cognition and behavior. It is also frequently cited as a domain in which sex differences have been established (e.g., [1][2][3][4]) and commonly affected in developmental, psychiatric, and neurological diseases with a sex-biased prevalence and/or prognosis (e.g., [5][6][7]). While it is generally assumed that these behavioral and clinical differences arise from a distinct organization of language in the brains of females and males, studies investigating potential sex-based anatomical and functional differences in language-related neural circuits are surprisingly limited [3,8] and have yielded inconclusive results [2,3,8,9]. ...
... It is also frequently cited as a domain in which sex differences have been established (e.g., [1][2][3][4]) and commonly affected in developmental, psychiatric, and neurological diseases with a sex-biased prevalence and/or prognosis (e.g., [5][6][7]). While it is generally assumed that these behavioral and clinical differences arise from a distinct organization of language in the brains of females and males, studies investigating potential sex-based anatomical and functional differences in language-related neural circuits are surprisingly limited [3,8] and have yielded inconclusive results [2,3,8,9]. Thus, for example, there are only two studies that have explored possible sex differences in gray matter volume (GM VOL ) at the inferior frontal gyrus (IFG) in children, and they reported contradictory sex effects (Blanton et al., males > females [10]; Wilke et al., females > males [11]). These and similar conflicting findings might lead to the interpretation that there are no sex differences in the IFG and in other language-processing brain areas. ...
... For instance, the studies of Blanton et al. [10] and Wilke et al. [11] also diverged in terms of sample size, statistical significance thresholds, and the inclusion of covariates of no interest in their analyses. The interplay of sample size (often small in such studies [2,8]) and significance thresholds (which have not always been corrected for multiple comparisons [12]) is of paramount importance because it essentially determines the likelihood of finding a statistically significant effect as well as their reliability/ reproducibility [22,23]. Furthermore, although it is known that language abilities and its neural underpinnings can be affected by variables such as age, handedness, educational and socio-economic level [12,[24][25][26], not all studies have statistically controlled for all these covariates. ...
Background
Sex differences in language-related abilities have been reported. It is generally assumed that these differences stem from a different organization of language in the brains of females and males. However, research in this area has been relatively scarce, methodologically heterogeneous and has yielded conflicting results.
Methods
Univariate and multivariate sex differences and similarities in gray matter volume (GM VOL ) within 18 essential language-processing brain areas were assessed in a sex-balanced sample (N = 588) of right-handed young adults. Univariate analyses involved location, spread, and shape comparisons of the females’ and males’ distributions and were conducted with several robust statistical methods able to quantify the size of sex differences and similarities in a complementary way. Multivariate sex differences and similarities were estimated by the same methods in the continuous scores provided by two distinct multivariate procedures (logistic regression and a multivariate analog of the Wilcoxon–Mann–Whitney test). Additional analyses were addressed to compare the outcomes of these two multivariate analytical strategies and described their structure (that is, the relative contribution of each brain area to the multivariate effects).
Results
When not adjusted for total intracranial volume (TIV) variation, “large” univariate sex differences (males > females) were found in all 18 brain areas considered. In contrast, “small” differences (females > males) in just two of these brain areas were found when controlling for TIV. The two multivariate methods tested provided very similar results. Multivariate sex differences surpassed univariate differences, yielding "large" differences indicative of larger volumes in males when calculated from raw GM VOL estimates. Conversely, when calculated from TIV-adjusted GM VOL , multivariate differences were "medium" and indicative of larger volumes in females. Despite their distinct size and direction, multivariate sex differences in raw and TIV-adjusted GM VOL shared a similar structure and allowed us to identify the components of the SENT_CORE network which more likely contribute to the observed effects.
Conclusions
Our results confirm and extend previous findings about univariate sex differences in language-processing areas, offering unprecedented evidence at the multivariate level. We also observed that the size and direction of these differences vary quite substantially depending on whether they are estimated from raw or TIV-adjusted GM VOL measurements.
... Small but consistent gender differences exist in early language and later literacy skills with boys trailing girls on average (OECD, 2019;Wallentin, 2009). At the same time, evidence shows that variation in early language and preliteracy skills is importantly influenced by the quality of the early home literacy environments Law et al., 2018;Payne et al., 1994;Zauche et al., 2016). ...
... Given that, as noted in the beginning, the quality of the home literacy environment has predictive relations to language and literacy skills, it is reasonable to suppose that gender differences in the early home literacy environment, should they exist, contribute to gender differences in early language and later literacy development. For oral language skills, the gender difference seems to taper off through childhood (Wallentin, 2009), but for reading skills, which build on both early language and preliteracy skills (National Early Literacy Panel, 2008), boys appear to have lower long-term outcomes than girls do. In all countries in OECD's 2018 PISA report, girls achieved significantly better reading outcomes than boys did around age 15 (OECD, 2019). ...
... As noted in the introduction, the early gender gap in language skills diminishes and may disappear during childhood (Wallentin, 2009), whereas for reading skills, which build on early language and preliteracy skills (National Early Literacy Panel, 2008), boys continue to achieve lower outcomes than girls. In Denmark, as in all other countries in OECD's 2018 PISA report, girls achieved significantly better reading outcomes than boys did by the end of primary school around age 15; on the other hand, girls and boys in Denmark performed similarly on math and science (OECD, 2019). ...
The present study examined whether parents’ and bilingual children’s own relative use of the heritage language vs. the majority language in the homes of bilingual children in Denmark before school start explains variance in 2nd grade majority language skills and reading skills. The study included two groups of children: the Mixed bilinguals group (defined by having a native Danish and a nonnative parent, N = 376) and the Heritage bilinguals group (defined by having parents who were both speakers of a Heritage language, N = 276). Four-stage hierarchical regression analyses showed that, after accounting for type of bilingualism, socioeconomic status (SES) and home literacy environment quality, relative use of the heritage vs. the majority language explained variance in 2nd grade Danish language comprehension scores, but did not explain variance in two reading scores, namely decoding and reading comprehension. In addition, a home literacy factor denoting book exposure (number of books, frequency of reading, library visits, and age of beginning shared book reading) was a significant predictor of both 2nd grade language and reading outcomes, whereas SES became a nonsignificant predictor when adding home literacy and language use predictors. We interpret the results to mean that parents’ and the child’s own relative use of the heritage language vs. the majority language before school start does not influence bilingual children’s early reading skills, whereas a supportive early home literacy environment is a positive predictor of reading skills independently of SES and parental majority language use and skill.
... For decades, research has been interested in exploring whether females and males possess different linguistic abilities. While the empirical evidence is unambiguous on the fact that some language-related disorders like autism, dyslexia and stuttering affect sexes differently [1][2][3] , with males consistently reported to be more affected than females, research conducted on typical samples has provided contrasting results 4 . Females have often been shown to perform better than males on a number of language measures. ...
... www.nature.com/scientificreports/ Second, and relatedly, the effect sizes reported for the "female advantage" in single studies are typically very small 4 , and when taken together with other predictors, sex accounts for only a minor share of the observed variance (e.g. 1-2% in 5 ). ...
Studies have repeatedly shown sex differences in some areas of language development, typically with an advantage for female over male children. However, the tested samples are typically small and the effects do not always replicate. Here, we used a meta-analytic approach to address this issue in a larger sample, combining seven fNIRS studies on the neural correlates of repetition- and non-repetition-based rule learning in newborns and 6-month-old infants. The ability to extract structural regularities from the speech input is fundamental for language development, it is therefore highly relevant to understand whether this ability shows sex differences. The meta-analysis tested the effect of Sex, as well as of other moderators on infants’ hemodynamic responses to repetition-based (e.g. ABB: “mubaba”) and non-repetition-based (e.g. ABC: “mubage”) sequences in both anatomically and functionally defined regions of interests. Our analyses did not reveal any sex differences at birth or at 6 months, suggesting that the ability to encode these regularities is robust across sexes. Interestingly, the meta-analysis revealed other moderator effects. Thus in newborns, we found a greater involvement of the bilateral temporal areas compared to the frontal areas for both repetition and non-repetition sequences. Further, non-repetition sequences elicited greater responses in 6-month-olds than in newborns, especially in the bilateral frontal areas. When analyzing functional clusters of HbR timetraces, we found that a larger right-left asymmetry for newborn boys in brain responses compared to girls, which may be interpreted in terms of a larger right-left asymmetry in cerebral blood flow in boys than in girls early in life. We conclude that extracting repetition-based regularities from speech is a robust ability with a well-defined neural substrate present from birth and it does not exhibit sex differences.
... Most studies on thinking deal with reasoning related to problem-solving and decision-making, and much less attention is paid to how people think in everyday situations (Wagoner, 2012). Nowadays, knowledge "that" (propositional) and knowledge "how" (procedural) are distinguished in literature (Pavese, 2021). ...
... Brain balancing (PACE system), internal thinking strategies, and teaching the seven narrative thinking and language levels assist learning (Sage, 2000). It also requires us to see thinking as an open process closely linked to social activity, which means that in the differentiated societies of today, various frameworks of thought are in use (Wagoner, 2012). Consequently, a need arises for a different approach to assessment and teaching (Sage & Mateucci, 2022). ...
The study assessed children’s ability to develop narratives and express ideas. It comprised 120 children (5-10 years), and differences in relation to age, sex, and economic area were measured. To this end, we compared four schools in 2 economic areas (poor and average). We used 2 picture and 2 story re-telling tasks designed to elicit narrations reflecting the generation of ideas in response to visual and auditory stimuli. Significant differences for age and sex but not economic areas were found. Suggestions are made for balancing brain activity and developing more creative approaches in teaching and assessment.
... Additionally, this girl's superiority or advantage in language development is even evident in later life, with males being more likely to stutter or experience aphasia after a stroke and slower to achieve rehabilitation (Joseph 2000). However, in a critical review, Wallentin (2009) noted that most studies reported sex differences based on p values, usually marginally significant. Furthermore, many studies had a small sample size; thus, the significance might be false positive. ...
... Furthermore, many studies had a small sample size; thus, the significance might be false positive. Therefore, Wallentin (2009) concluded there might be no sound evidence for gender differences in language development. However, this literature review has focused on adult studies, leaving the gender difference in young children unconfirmed. ...
This study aimed to verify the sex differences seen in our previous study on early syntactic development among Cantonese-speaking children with the same corpus design but a different Chinese language: Mandarin. The utterances produced during half-hour play activities by 192 Beijing children, ranging from 3 to 6 years, were collected in the Early Child Mandarin Corpus and analyzed in this study. Their syntactic development was measured in terms of mean length of utterance (MLU), sentence type and structure, syntactic complexity, and verb pattern. The statistical analyses indicated significant age differences in MLU, sentence types and structures, and syntactic complexity. However, no sex or age-by-sex differences in MLU were found. This negative evidence indicates that sex difference is neither universal nor cross-language. The implications for early childhood education and future studies are discussed.
... In fact, the extraction of well-pronounced differences between males and females from functional brain imaging data has been far from trivial for a long time. Many studies reported no or only very small and inconsistent findings especially when dealing with functional data related to cognitive tasks in psychological domains [106][107][108][109]. But also for resting-state fMRI data, it has been claimed that no differences between males and females can be detected [110]. ...
Personalized modeling of the resting-state brain activity implies the usage of dynamical whole-brain models with high-dimensional model parameter spaces. However, the practical benefits and mathematical challenges originating from such approaches have not been thoroughly documented, leaving the question of the value and utility of high-dimensional approaches unanswered. Studying a whole-brain model of coupled phase oscillators, we proceeded from low-dimensional scenarios featuring 2–3 global model parameters only to high-dimensional cases, where we additionally equipped every brain region with a specific local model parameter. To enable the parameter optimizations for the high-dimensional model fitting to empirical data, we applied two dedicated mathematical optimization algorithms (Bayesian Optimization, Covariance Matrix Adaptation Evolution Strategy). We thereby optimized up to 103 parameters simultaneously with the aim to maximize the correlation between simulated and empirical functional connectivity separately for 272 subjects. The obtained model parameters demonstrated increased variability within subjects and reduced reliability across repeated optimization runs in high-dimensional spaces. Nevertheless, the quality of the model validation (goodness-of-fit, GoF) improved considerably and remained very stable and reliable together with the simulated functional connectivity. Applying the modeling results to phenotypical data, we found significantly higher prediction accuracies for sex classification when the GoF or coupling parameter values optimized in the high-dimensional spaces were considered as features. Our results elucidate the model fitting in high-dimensional parameter spaces and can contribute to an improved dynamical brain modeling as well as its application to the frameworks of inter-individual variability and brain-behavior relationships.
... Sex differences in left-hemispheric dominance and language development have been controversial [26]. Prior fMRI studies have shown that women show more bilateral patterns of activity during language tasks than men [27][28][29]. ...
The relationship between brain asymmetry and inattention, and their heritability is not well understood. Utilizing advanced neuroimaging, we examined brain asymmetry with data from the Adolescent Brain Cognitive Development (ABCD; n = 8943; 9–10 y) and the Human Connectome Project (HCP) cohorts (n = 1033; 5–100 y). Data-driven metrics from resting-state fMRI and morphometrics revealed reproducible and stable brain asymmetry patterns across the lifespan. In children, high levels of inattention were highly heritable (61%) and linked to reduced leftward asymmetry of functional connectivity in the dorsal posterior superior temporal sulcus (dpSTS), a region interconnected with a left-lateralized language network. However, reduced dpSTS asymmetry had low heritability (16%) and was associated with lower cognitive performance suggesting that non-genetic factors, such as those mediating cognitive performance, might underlie its association with dpSTS asymmetry. Interventions that enhance cognition might help optimize brain function and reduce inattention.
... Therefore, the present study provides new insights into this interaction by showing that below-average fine motor skills have a greater adverse effect on spelling performance in girls than in boys. Although there are some studies reporting sex differences in language lateralization (for an overview see Wallentin, 2009), which might also be associated with motor abilities (e.g., corpus callosum motor fibers; Grohs et al., 2018), research to date does not clearly suggest that sex differences in hemispheric asymmetry and cognitive performance are correlated (for a further overview see Hirnstein et al., 2019). However, the developmental perspective of this relation has not yet been investigated sufficiently. ...
Background
Children are using digital devices earlier and more frequently than they did years ago. At the same time fine motor skills and the spelling performance of primary school children have deteriorated over the last years. There is some evidence for a relationship between fine motor skills and spelling performance, while the role of test mode in this context is still unknown. Therefore, the aim of the present study was to evaluate the relation between parent-reported fine motor skills and spelling performance in different test modes.
Methods
The spelling performance of German children in 3rd and 4th grade (age: 8–12 years) was examined, first in digital test mode (N = 3,453; 49.1% girls) and then in paper-pencil mode (N = 225; 44% girls). Fine motor skills were assessed using a parental questionnaire.
Results
The results confirm earlier findings of a positive relation between spelling performance and fine motor skills and reveal that using digital test mode leads to neither an immediate improvement nor a deterioration in spelling performance in children with low fine motor skills. Below-average fine motor skills appeared to have a more adverse effect on spelling performance in girls than in boys. Also, fine motor skills had an influence on school grade in German over and above its influence on reading and spelling abilities.
Conclusion
Switching from paper-pencil to digital testing does not seem to bring immediate improvement for children with low fine motor skills, but is not a disadvantage either.
... Artikulacioni poremećaji bili su češći kod dečaka (54%), nego kod devojčica (46%) (Ibid.). Međutim, razlike između dečaka i devojčica, koje postoje u ranim fazama razvoja govora i učenja jezika, uzrastom postupno nestaju (Wallentin, 2009). ...
Pravovremeno otkrivanje govorno-jezičkih problema i pružanje adekvatne podrške jedan je od značajnih zadataka porodice i predstavnika ranog formalnog obrazovanja. Stoga je cilj istraživanja koje je sprovedeno kvantitativnom i kvalitativnom metodom na uzorku od 110 vaspitača u predškolskim ustanovama u Republici Srbiji na teritoriji Čačka, Loznice i Sremske Mitrovice bio da se ispitaju mišljenja i stavovi vaspitača o govorno-jezičkim problemima kod dece tipičnog razvoja, kao i o načinima pružanja podrške. Rezultati su pokazali da je najveći broj vaspitača mišljenja da deca imaju umerene govorno-jezičke probleme, i to najčešće u vidu kašnjenja u govorno-jezičkom razvoju, zatim probleme s izgovorom, teškoće u pronalaženju reči koje su im potrebne za izražavanje svojih misli, te probleme koji su u vezi s gramatikom: netačna upotreba glagola, imenica i prideva, kao i nepravilna upotreba padeža i roda. Vaspitači dalje smatraju da je neophodan veći stepen uključivanja stručnih saradnika, pre svih logopeda, kao i roditelja, kao i dalje stručno usavršavanje u ovoj oblasti svih relevantnih aktera. Ova saznanja mogu biti od koristi predškolskim ustanovama u razvijanju efikasnih strategija i programa podrške u radu sa decom predškolskog uzrasta tipičnog razvoja koja imaju govorno-jezičke probleme
... As the current study did not observe an interaction between sex and age, the discrepancy between our results and Kostilainen et al. (2018) could not be explained by age differences. The early MMR primarily reflects lower level sensory processing, and further research with larger sample sizes is needed to determine whether the sex effect on this neurophysiological component implies functional differences in automatic auditory processing of emotional prosody between male and female infants (McClure, 2000;Wallentin, 2009). Since there is limited literature concerning the influence of sex on infants' MMRs to changes in emotional vocal cues, the current findings regarding sex differences should be considered exploratory and warrant further investigation in future studies. ...
Purpose
This study aimed to investigate infants' neural responses to changes in emotional prosody in spoken words. The focus was on understanding developmental changes and potential sex differences, aspects that were not consistently observed in previous behavioral studies.
Method
A modified multifeature oddball paradigm was used with emotional deviants (angry, happy, and sad) presented against neutral prosody (standard) within varying spoken words during a single electroencephalography recording session. The reported data included 34 infants (18 males, 16 females; age range: 3–12 months, average age: 7 months 26 days).
Results
Infants exhibited distinct patterns of mismatch responses (MMRs) to different emotional prosodies in both early (100–200 ms) and late (300–500 ms) time windows following the speech onset. While both happy and angry prosodies elicited more negative early MMRs than the sad prosody across all infants, older infants showed more negative early MMRs than their younger counterparts. The distinction between early MMRs to angry and sad prosodies was more pronounced in younger infants. In the late time window, angry prosody elicited a more negative late MMR than the sad prosody, with younger infants showing more distinct late MMRs to sad and angry prosodies compared to older infants. Additionally, a sex effect was observed as male infants displayed more negative early MMRs compared to females.
Conclusions
These findings demonstrate the feasibility of the modified multifeature oddball protocol in studying neural sensitivities to emotional speech in infancy. The observed age and sex effects on infants' auditory neural responses to vocal emotions underscore the need for further research to distinguish between acoustic and emotional processing and to understand their roles in early socioemotional and language development.
Supplemental Material
https://doi.org/10.23641/asha.27914553
... Evidence suggests that the quality of early home literacy environments significantly influences the diversity in early language and preliteracy skills [70,88]. Similarly, some studies have shown gender differences in literacy environments at home, with a preference for girls [89,90]. One study indicated that the home literacy environment provided to boys is generally poorer than that provided to girls [69]. ...
Early literacy skills, the foundational abilities necessary for the development of literacy, must be examined holistically in preschool children. This study aimed to investigate early literacy skills in preschool children and determine how variables related to literacy development can be clustered by using a dendrogram. The study was conducted on 166 preschool children (75 female, 91 male; mean age: 65.9±4.4 months). Hierarchical cluster analysis (CA) was used to find the variable clustering trends. The 44 variables related to literacy (sociodemographic factors related to the child and family, child–parent relationship, child’s behavior, and social, sensory integration, motor, and auditory linguistic skills) that were closest to each other in the dendrogram were clustered, and the situation was summarized by reducing them to two main clusters and six sub-clusters. This study elaborates on the implications of reducing multivariate complexity using CA. It is recommended that the relationships among the variables in this dendrogram structure are considered when new hypotheses and studies related to early literacy are designed.
... Memory tasks, such as the Digit and Corsi span tests, the short story tests, and the RAVLT show the expected interindividual variability. Moreover, the majority of VaNIT scores resulted to be associated with demographics in agreement with the neuropsychological literature, that is, sex differences have been detected within language and visuospatial domains (Hugdahl et al., 2006;Ramos-Loyo et al., 2022;Wallentin, 2009;Wang, 2020), involute trends were present with increasing age (Robinson et al., 2022;Vallesi et al., 2021), whereas education positively influences performances (Bianchi & Dai Prà, 2008;Opdebeeck et al., 2016). Finally, promising preliminary evidence of validity has been provided concerning VaNIT-VS novel or revised tasks and outcomes. ...
Objective: There is a pressing need to develop alternatives to the traditional pencil-and-paper, in-ward neuropsychological testing. Remote neuropsychological assessment (tele-neuropsychology; TeleNP) would be extremely useful not only in emergencies but also to reach several patients who cannot reach the hospital. However, there is a lack of instruments that are specifically designed for TeleNP that allow a comprehensive evaluation of cognitive functions. Here, we describe the development and implementation of Valutazione Neuropsicologica Interattiva in Telemedicina (VaNIT), a TeleNP tool including several neuropsychological tests that can be administered remotely. VaNIT was designed and developed to match three key specific requirements: (1) multidimensionality of the assessment—VaNIT includes 29 tests assessing cognitive efficiency, linguistic abilities, memory, and visuospatial functions; (2) evidence-based test selection; (3) interactive virtual environment—developed on a web-based platform with integrated video call. Method: In a pilot study, we explored VaNIT’s usability and feasibility in healthy individuals. Forty healthy individuals (20 males; range = 18–87) underwent the pilot study via PC administration. Results: Age and education consistently affected the vast majority of measures, whereas no relevant sex differences were detected. Novel tasks proved to sufficiently converge to well-known measures at the within-domain level. Conclusions: VaNIT represents an example of digital innovation in the medical area that aims at preserving the interactive nature of the neuropsychological examination. Ultimately, the goal of this work is to reach clinicians and researchers working in the field to make a joint effort in order to rapidly provide diagnostic tools that could in the future be part of the standard toolkit of the neuropsychologist.
... The increased risk of language impairment in boys following neonatal hypoglycemia, in contrast to girls, could potentially be attributed to the well-established sex differences in language development, with girls acquiring language faster than males, 33,34 and having advantage in several basic linguistic domains by mid-childhood. 35,36 Boys had greater variability in language development and a higher overrepresentation at the lower end of the language proficiency spectrum. ...
Objective
To determine the relationship between transient neonatal hypoglycemia in at-risk infants and neurocognitive function at 6-7 years of corrected age.
Study design
The pre-hPOD Study involved children born with at least one risk factor for neonatal hypoglycemia. Hypoglycemia was defined as ≥1 consecutive blood glucose concentrations <47 mg/dl (2.6 mmol/L), severe as <36 mg/dl (2.0 mmol/L), mild as 36 to <47 mg/dL (2.0 to <2.6 mmol/L), brief as 1 to 2 episodes, and recurrent as ≥3 episodes. At 6-7 y children were assessed for cognitive and motor function (NIH-Toolbox), learning, visual perception and behavior. The primary outcome was neurocognitive impairment, defined as >1 SD below the normative mean in ≥1 Toolbox tests. The eight secondary outcomes covered children's cognitive, motor, language, emotional-behavioral, and visual perceptual development. Primary and secondary outcomes were compared between children who did and did not experience neonatal hypoglycemia, adjusting for potential confounding by gestation, birthweight, sex and receipt of prophylactic dextrose gel (pre-hPOD intervention). Secondary analysis included assessment by severity and frequency of hypoglycemia.
Results
Of 392 eligible children, 315 (80%) were assessed at school age (primary outcome, n=308); 47% experienced hypoglycemia. Neurocognitive impairment was similar between exposure groups (hypoglycemia 51% vs. 50% no hypoglycemia; aRD -4%, 95%CI -15%, 7%). Children with severe or recurrent hypoglycemia had worse visual motion perception and increased risk of emotional-behavioral difficulty.
Conclusion
Exposure to neonatal hypoglycemia was not associated with risk of neurocognitive impairment at school-age in at-risk infants, but severe and recurrent episodes may have adverse impacts.
... For instance, it has been proposed that prenatal exposure to testosterone may facilitate neuronal pruning in the corpus callosum, leading to a decrease in interhemispheric transfer and an increase in hemispheric lateralization in males compared to females [60]. Indeed, previous research reported that, on average, males exhibit greater hemispheric specialization than females [61][62][63][64][65]. Additionally, research relating callosal anatomy to manual lateralization suggested the importance of considering not only sex differences but also the interaction between sex and hand preference [66][67][68]. ...
Previous research yielded inconsistent findings regarding whether manual lateralization (e.g., a distinct and consistent hand preference) affects manual performance during infancy and early childhood. The aim of the current study was to determine whether manual lateralization, viewed as a marker of hemispheric lateralization, is associated with infants’ performance in role-differentiated bimanual manipulation (RDBM) and tool use. This longitudinal study assessed 158 typically developing infants (91 males, aged 9.13 ± 0.15 months at baseline) monthly during the 9–14-month period. Developmental trajectories for manual lateralization in object acquisition were related to those for RDBM and tool use, even after accounting for potential sex differences. All statistical analyses were conducted using Hierarchical Linear Modeling software (version 6). Advanced RDBM performance was associated with a lower magnitude of manual lateralization and a higher tendency among infants to use both hands for object acquisition. No significant relation was found between the magnitude of manual lateralization and tool-use performance. Thus, the current results highlight the importance of hand coupling for enhanced RDBM performance. Moreover, across all ages, females outperformed males in sophisticated RDBMs, possibly due to their less pronounced manual lateralization and a greater inclination towards bimanual object acquisition—factors that appear to facilitate RDBM performance.
... Especially odor identification tests show superiority of female participants (Sorokowski et al. 2019), mainly in younger adults (Wang et al. 2019). Different potential causes have been put forward to why this is the case, including superior naming abilities in women compared to men ((Larsson et al., 2004) although see (Wallentin 2009)), as well as hormonal or anatomical differences (Sorokowski et al. 2019). ...
The sense of smell allows for the assessment of the chemical composition of volatiles in our environment. Different factors are associated with reduced olfactory function, including age, sex, as well as health and lifestyle conditions. However, most studies that aimed at identifying the variables that drive olfactory function in the population suffered from methodological weaknesses in study designs and participant selection, such as the inclusion of convenience sample or only of certain age groups, or recruitment biases.
We aimed to overcome these issues by investigating the Cooperative Health Research in South Tyrol (CHRIS) cohort, a population-based cohort, by using a validated odor identification test. Specifically, we hypothesized that a series of medical, demographic and lifestyle variables is associated with odor identification abilities. In addition, our goal was to provide clinicians and researchers with normative values for the Sniffin’ Sticks identification set, after exclusion of individuals with impaired nasal patency.
We included 6,944 participants without acute nasal obstruction and assessed several biological, social, and medical parameters. A basic model determined that age, sex, years of education, and smoking status together explained roughly 13% of the total variance in the data. We further observed that variables related to medical (positive screening for cognitive impairment and for Parkinson’s disease, history of skull fracture, stage 2 hypertension) and lifestyle (alcohol abstinence) conditions had a negative effect on odor identification scores. Finally, we provide clinicians with normative values for both versions of the Sniffin’ Sticks odor identification test, i.e. with 16 items and with 12 items.
... This suggests that men might be more likely to develop pure alexia after stroke than women. Although some scholars laid an emphasis on similarities between men's and women's brain organization for language [22][23][24], others proposed that men have more left lateralized language function than women [25,26]. For example, studies using event-related potential measures revealed sex differences in lateralization pattern [27]. ...
Very few cases of Chinese pure alexia have been reported to date. We aim to summarize the linguistic features and neuropsychological profiles of Chinese pure alexia through a case series study.
11 consecutive patients with post-stroke Chinese pure alexia and 11 healthy controls were included. The Aphasia Battery of Chinese (ABC) and 68-Chinese character oral reading test (68-character test) were used to evaluate the reading and writing ability. Reading errors were classified based on the performance of 68-character test. Neuropsychological profiles were evaluated with corresponding scales. The possible correlation between the reading ability and the writing ability or neuropsychological performance was analyzed.
The patients had a correct rate of 43.7 ± 23.2% in the 68-character test, significantly lower (P < 0.001) than that of controls. Shape-similar error was the most common type of reading error (101/209, 48.3%). The ABC total writing score rate of the patients ranged from 68.9% to 98.7% (median, 90.5%), significantly lower (P < 0.001) than that of the controls. The patients also showed worse performance in MMSE, auditory verbal learning test, Boston naming test, intersecting pentagons copying and clock-drawing test (all P < 0.05). In the patient group, the correct rate of 68-character test was significantly correlated with the ABC total writing score rate (P = 0.008), the score rate of Boston naming test (P = 0.017), and the clock-drawing test score (P = 0.010).
Shape-similar errors may be a characteristic of Chinese pure alexia. The correlation between visuospatial dysfunction and pure alexia might explain the frequent occurrence of shape-similar errors in Chinese pure alexia.
... Bangladesh (Hamadani et al., 2006;Hossain et al., 2022), Nepal (Ranjitkar et al., 2019), and India (Andrew et al., 2020). This may be due to biological factors (Wallentin, 2009), although no further support for this theory was found in other studies (Sommer et al., 2004). ...
Background
Children's development is multifactorial. Although there have been several studies exploring the association of children's development with maternal, child, and environmental factors, we are unaware of any study that assessed those factors in children whose mothers were enrolled in a social safety net programme in low‐ and middle‐income countries. This study aimed to identify the factors associated with disadvantaged children's cognitive, language, and motor development at age 6–16 months in deprived settings of urban Bangladesh and to identify relative importance of these factors of children's development. We also explored if there were any gender differences in child development.
Methods
This cross‐sectional study was conducted in a deprived setting of urban Bangladesh. Bayley III was used for assessing children's cognitive, language, and motor development. Multivariable linear regression model was used to find the factors associated with children's development, and dominance analysis was used to explore the relative importance of the factors.
Results
Out of the total 599 mother–child dyads, 303 (50.58%) were girls. The factors associated with children's development were length‐for‐age Z‐score (cognitive: B = 1.21 [95% CI = 0.31, 2.11], P = 0.008; language: 1.67 [0.79, 2.55] P < 0.001; motor: 2.15 [1.01, 3.29] P < 0.001) and home environment (cognitive: 0.58 [0.27, 0.89] P < 0.001; language: 0.59 [0.27, 0.92], P < 0.001; motor: 0.44 [0.09, 0.79] P = 0.013). Girls had higher cognitive (1.90 [0.17, 3.6], P = 0.031) and language (2.53 [0.55, 4.51], P = 0.013) development compared with boys. Families with a higher number of under five children within the households had lower language (−1.57 [−2.78, −0.36], P = 0.011) development. Violence against the mother and the families' food security status were not associated with the children's development. Children's length‐for‐age Z‐score (27%) and home stimulation environment (23%) were the most important factors of cognitive development.
Conclusion
Children's nutritional status and home environment are important factors for disadvantaged children's development in deprived urban settings of Bangladesh. Both early child development‐focussed parenting and nutrition interventions should be considered when designing child development programmes in urban settings in low‐ and middle‐income countries.
... This inconsistency regarding the impact of sex in language recovery could be probably attributed to recent studies which report that in controls, sex differences in brain structure or function, although present, do not necessarily reflect variations in language performance [64,65]. The emergence of sex differences then could depend on the modality of the language task, such as perception or speech fluency, and not specifically on the different language lateralization of brain structure per se [66]. ...
Post-stroke language recovery remains one of the main unresolved topics in the field of aphasia. In recent years, there have been efforts to identify specific factors that could potentially lead to improved language recovery. However, the exact relationship between the recovery of particular language functions and possible predictors, such as demographic or lesion variables, is yet to be fully understood. In the present study, we attempted to investigate such relationships in 42 patients with aphasia after left hemisphere stroke, focusing on three language domains: auditory comprehension, naming and speech fluency. Structural imaging data were also obtained for the identification of the lesion sites. According to our findings, patients demonstrated an overall improvement in all three language domains, while no demographic factor significantly contributed to aphasia recovery. Interestingly, specific lesion loci seemed to have a differential effect on language performance, depending on the time of testing (i.e., acute/subacute vs. chronic phase). We argue that this variability concerning lesion–deficit associations reflects the dynamic nature of aphasia and further discuss possible explanations in the framework of neuroplastic changes during aphasia recovery.
... Although the language lateralization pattern in healthy people has been found to be related to a variety of factors (e.g. age, gender, handedness, and gene), most people still showed typical left language lateralization in brain activation (Shaywitz et al. 1995;Crow et al. 1998;Pujol et al. 1999;Knecht et al. 2000;Szaf larski et al. 2002Szaf larski et al. , 2006Szaf larski et al. , 2012Dehaene-Lambertz et al. 2003;Wallentin 2009;Perlaki et al. 2013;Ocklenburg et al. 2014). In patients, the measurement of language laterality was important in epilepsy and brain tumors before surgery, which could avoid postoperative language deficit as much as possible (Baxendale et al. 2008;Arora et al. 2009;Ellmore et al. 2010;Jones et al. 2011;Pillai and Zaca 2011;Partovi et al. 2012;Zacà et al. 2012;Janecek et al. 2013;Stewart et al. 2014). ...
The hemispheric laterality of language processing has become a hot topic in modern neuroscience. Although most previous studies have reported left-lateralized language processing, other studies found it to be bilateral. A previous neurocomputational model has proposed a unified framework to explain that the above discrepancy might be from healthy and patient individuals. This model posits an initial symmetry but imbalanced capacity in language processing for healthy individuals, with this imbalance contributing to language recovery disparities following different hemispheric injuries. The present study investigated this model by analyzing the lateralization patterns of language subnetworks across multiple attributes with a group of 99 patients (compared to nonlanguage processing) and examining the lateralization patterns of language subnetworks in subgroups with damage to different hemispheres. Subnetworks were identified using a whole-brain network-based lesion-symptom mapping method, and the lateralization index was quantitatively measured. We found that all the subnetworks in language processing were left-lateralized, while subnetworks in nonlanguage processing had different lateralization patterns. Moreover, diverse hemisphere-injury subgroups exhibited distinct language recovery effects. These findings provide robust support for the proposed neurocomputational model of language processing.
... Results revealed robust sex differences across verbal fluency measures (female advantage for Total, Fruit, Vegetable, but not Animal), with males performing lower on Fruit and Vegetable Fluency. Unlike verbal memory (e.g., "female verbal advantage") that has evidence of sexual dimorphism in brain structure and biomarker data (Sundermann et al., 2020;Sundermann et al., 2016), after early childhood, language-based differences in cognition, lateralization, and morphometry do not differ between sexes (Wallentin, 2009). Discrepancies in sex effects between fluency categories have been repeatedly observed across samples within the US and from different countries. ...
Objective
Normative neuropsychological data are essential for interpretation of test performance in the context of demographic factors. The Mayo Normative Studies (MNS) aim to provide updated normative data for neuropsychological measures administered in the Mayo Clinic Study of Aging (MCSA), a population-based study of aging that randomly samples residents of Olmsted County, Minnesota, from age- and sex-stratified groups. We examined demographic effects on neuropsychological measures and validated the regression-based norms in comparison to existing normative data developed in a similar sample.
Method
The MNS includes cognitively unimpaired adults ≥30 years of age ( n = 4,428) participating in the MCSA. Multivariable linear regressions were used to determine demographic effects on test performance. Regression-based normative formulas were developed by first converting raw scores to normalized scaled scores and then regressing on age, age ² , sex, and education. Total and sex-stratified base rates of low scores ( T < 40) were examined in an older adult validation sample and compared with Mayo’s Older Americans Normative Studies (MOANS) norms.
Results
Independent linear regressions revealed variable patterns of linear and/or quadratic effects of age ( r ² = 6–27% variance explained), sex (0–13%), and education (2–10%) across measures. MNS norms improved base rates of low performance in the older adult validation sample overall and in sex-specific patterns relative to MOANS.
Conclusions
Our results demonstrate the need for updated norms that consider complex demographic associations on test performance and that specifically exclude participants with mild cognitive impairment from the normative sample.
... Yet another factor that may influence metaphor interpretation is gender. It is generally believed that girls show better language skills than boys, however, the results of studies involving different linguistic domains and participants of different ages show a complex picture [52]. Large-scale studies involving parent reports of language skills of young children aged 6 months to 2 years indicate a slight, but consistent advantage of girls over boys in the use of communicative gestures, expressive vocabulary and early word combinations [53][54][55]. ...
Metaphor understanding can be tricky for children until mid-childhood, yet some research suggests that pre-schoolers are already competent. Many factors have been proposed to play a role in the development of metaphor comprehension. In this study we focus on two obvious contenders that have been overlooked in recent years: general language skills and socioeconomic status (SES). Two-hundred and seventy-two children, aged from 2;11 to 11;04 (146 girls) were recruited from 21 British schools and nurseries. Their SES was established using a composite measure linked to school location, while general language skills were assessed using a standardised measure of vocabulary comprehension. Novel metaphor comprehension was tested with a simple reference assignment task. Our study confirms that children interpret novel metaphors confidently from the age of 4. Our findings indicate that novel metaphor understanding is associated with age and, importantly, that it is linked to vocabulary skills, as well as SES, but not gender. These two factors should therefore be considered in future research on metaphor development, as well as intervention and education.
... Verbal fluency tasks assess the ability to generate verbal information (Patterson, 2011). Although it is debated (e. g., Hyde and Linn, 1988;Wallentin, 2009), recent meta-analyses showed robust advantages in women compared to men in narrative-writing fluency (Schultheiss et al., 2021) and phonemic verbal fluency (Hirnstein et al., 2022). Though a detrimental effect of testosterone has been put forth to explain these findings (O'Connor et al., 2001;Van Goozen et al., 1995;Wolf et al., 2000), this female-dominant advantage has mostly been attributed to estradiol (Hampson, 1990;Maki et al., 2002;Schultheiss et al., 2021), but not consistently (Scheuringer et al., 2017;Schultheiss and Zimni, 2015). ...
... However, since infant MMRs can manifest as either positive or negative deflections, caution is needed in interpreting the sex differences observed in the current study with infants aged 3 to 12 months (Etchell et al., 2018). The early MMR primarily reflects lower-level sensory processing, and further research with larger sample sizes is needed to determine whether the sex effect on this neurophysiological component implies functional differences in automatic auditory processing of emotional prosody between male and female infants (McClure, 2000;Wallentin, 2009). There was no interaction between sex and emotional categories, suggesting that the differential early MMR amplitudes in male and female infants were not specific to certain emotions. ...
This study examined infants' neural responses to emotional prosody in natural speech. A multi-feature oddball paradigm was used with 34 3~11 month-old infants. Results showed distinct early (100-200 ms) and late (300-500 ms) mismatch responses to different emotional prosodies. Older infants had more negative early responses with happy and angry prosodies evoking stronger responses compared to sad prosody while younger infants showed a clearer distinction between angry and sad prosodies. In the late time window, angry prosody elicited more negative responses than sad prosody with younger infants showing more distinct responses between these two prosodies. Males exhibited stronger early mismatch responses than females. These findings call for further research on the implications for socio-emotional and language development.
Keywords: emotional prosody, mismatch response (MMR), sex differences, infancy
... High testosterone links to competition and low testosterone to nurturance, constructs that are not synonymous with masculinity and femininity (van Anders, 2013). Crucially, even when scientists nd sex-based brain di erences (Ruigrok et al., 2014), they do not always nd a clear relationship between those di erences and behavioral sex dissimilarities (Wallentin, 2009). ...
This volume contains 30 chapters that provide an up-to-date account of key topics and areas of research in political psychology. In general, the chapters apply what is known about human psychology to the study of politics. Chapters draw on theory and research on biopsychology, neuroscience, personality, psychopathology, evolutionary psychology, social psychology, developmental psychology, cognitive psychology, and intergroup relations. Some chapters address the political psychology of political elites—their personality, motives, beliefs, and leadership styles, and their judgments, decisions, and actions in domestic policy, foreign policy, international conflict, and conflict resolution. Other chapters deal with the dynamics of mass political behavior: voting, collective action, the influence of political communications, political socialization and civic education, group-based political behavior, social justice, and the political incorporation of immigrants. Research discussed in the volume is fueled by a mix of age-old questions and recent world events.
... High testosterone links to competition and low testosterone to nurturance, constructs that are not synonymous with masculinity and femininity (van Anders, 2013). Crucially, even when scientists nd sex-based brain di erences (Ruigrok et al., 2014), they do not always nd a clear relationship between those di erences and behavioral sex dissimilarities (Wallentin, 2009). ...
This volume contains 30 chapters that provide an up-to-date account of key topics and areas of research in political psychology. In general, the chapters apply what is known about human psychology to the study of politics. Chapters draw on theory and research on biopsychology, neuroscience, personality, psychopathology, evolutionary psychology, social psychology, developmental psychology, cognitive psychology, and intergroup relations. Some chapters address the political psychology of political elites—their personality, motives, beliefs, and leadership styles, and their judgments, decisions, and actions in domestic policy, foreign policy, international conflict, and conflict resolution. Other chapters deal with the dynamics of mass political behavior: voting, collective action, the influence of political communications, political socialization and civic education, group-based political behavior, social justice, and the political incorporation of immigrants. Research discussed in the volume is fueled by a mix of age-old questions and recent world events.
... Numerous studies show that females outperform males at perceptual speed tasks, verbal tasks, and ne motor skills (11)(12)(13). Verbal uency (the ability to generate words based on a speci c category or condition) and verbal memory (the ability to memorize words and other abstractions involving language) are among those cognitive functions that have received the most attention (14)(15)(16). Meta-analyses have shown effect sizes in verbal memory and verbal uency tasks ranging between 0.27 and 0.34 (17)(18)(19). The largest effect sizes are observed with the California Verbal Learning Task (20), with a mean of 0.48. ...
Background: Sexually polymorphic cognition (SPC) results from the interaction between biological (birth-assigned sex (BAS), sex hormones) and sociocultural (gender identity, gender roles, sexual orientation) factors. The literature remains quite mixed regarding the magnitude of the effects of these variables. This project used a battery of classic cognitive tests designed to assess the influence of sex hormones on cognitive performance. At the same time, we aimed to assess the inter-related and respective effects that BAS, sex hormones, and gender-related factors have on SPC.
Methods: We recruited 222 adults who completed eight cognitive tasks that assessed a variety of cognitive domains during a 150-minute session. Subgroups were recruited as follows: cisgender heterosexual men (n = 46), cisgender non-heterosexual men (n = 36), cisgender heterosexual women (n = 36), cisgender non-heterosexual women (n = 38), gender diverse (n = 66). Saliva samples were collected before, during, and after the test to assess testosterone, estradiol, progesterone, cortisol, and dehydroepiandrosterone. Psychosocial variables were derived from self-report questionnaires.
Results: Cognitive performance reflects sex and gender differences that are partially consistent with the literature. Interestingly, biological factors seem to better explain differences in male-typed cognitive tasks (e.g., spatial), while psychosocial factors seem to better explain differences in female-typed cognitive tasks (e.g., verbal).
Conclusion: Our results provide a solid foundation for better understanding SPC by going beyond BAS as a binary. We highlight the importance of treating sex as a biological factor and gender as a sociocultural factor together since they collectively influence SPC.
... By 24 months toddlers can produce short sentences and short questions. Independent of the native language, on average girls acquire language earlier than boys but sex differences are small (Wallentin, 2009). ...
We wrote this book for undergraduate and graduate students of the helping professions. It is a complete view of development from an ethological and cognitive behavioral perspective. It is unique in its synthesis of biological, anthropological and psychological accounts of development.
... The influence of gender on pragmatic language development was not directly discussed in the analyzed tables. However, existing literature suggests that there may be gender-related differences in language development, with females typically outperforming males in various language tasks (Wallentin, 2009). Further research is needed to explore these potential gender-related differences in pragmatic language development and to determine the necessity of gender-specific interventions. ...
This cross-sectional study examined the relationship between gender, age, and pragmatic language development in n = 77 Italian preschool children (49-84 months) with and without neurodevelopmental disorders. The sample included 62 children without psychiatric history (n = 34 females, n = 27 males) and n = 15 children with psychiatric history (2 females, n = 13 males). Eight cases (n = 6 males, n = 2 females, 59-75 months) were matched for age and gender. The neurodevelopmental disorder group used the Targeted Observation of Pragmatics in Children's Conversations (TOPICC) tool. Pragmatic language skills were assessed with the Pragmatic Language Abilities (APL), Children's Communication Checklist-Version 2 (CCC-2), and TOPICC scales. Results showed no significant relationship between gender and pragmatic language development subscales, except for a marginally significant relationship with figurative metaphor scores. Age was positively correlated with verbal metaphor, metaphor, implied meaning, and overall pragmatic language skills, but not with figurative metaphor or situations scores. Paired samples t-tests and Wilcoxon tests compared matched groups, revealing significant differences between children with and without neurodevelopmental disorders on the TOPICC, APL, and CCC-2 tools. The findings highlight the importance of early identification and intervention for children with pragmatic language impairment (PLI) and the need for further research with larger samples.
... In the largest study on record, 13 where the verbal scores on the Stanford Achievement Test for nearly a million graduating high school seniors in 1985 were compared, males came out on top, by a small but statistically reliable margin. Still, the opinion persists that females have a statistically discernible advantage over males in language, 14 an opinion supported by most investigations that have yielded reliable results and by continuing research of high quality. [15][16][17] Since both sexes must use language extensively, it seems unsurprising that whatever differences do occur must be limited to show small effect sizes. ...
Seeking to discern the earliest sex differences in language-related activities, our focus is vocal activity in the first two years of life, following up on recent research that unexpectedly showed boys produced significantly more speech-like vocalizations (protophones) than girls during the first year of life.We now bring a much larger body of data to bear on the comparison of early sex differences in vocalization, data based on automated analysis of all-day recordings of infants in their homes. The new evidence, like that of the prior study, also suggests boys produce more protophones than girls in the first year and offers additional basis for informed speculation about biological reasons for these differences. More broadly, the work offers a basis for informed speculations about foundations of language that we propose to have evolved in our distant hominin ancestors, foundations also required in early vocal development of modern human infants.
... On a cognitive level, this sex divergence in brain lateralization was thought to explain why women outperformed the opposite sex in language tasks such as verbal fluency tests on average; as well as why men were supposed to typically exhibit greater spatial skills, such as in three-dimensional mental rotation tasks 109,110 . However, the respective effect sizes have been small and several metaanalyses called into question the organizational differences related to lateralization and language processing [111][112][113] . ...
Ischemic cerebrovascular events often lead to aphasia. Previous work provided hints that such strokes may affect women and men in distinct ways. Women tend to suffer strokes with more disabling language impairment, even if the lesion size is comparable to men. In 1401 patients, we isolate data-led representations of anatomical lesion patterns and hand-tailor a Bayesian analytical solution to carefully model the degree of sex divergence in predicting language outcomes~3 months after stroke. We locate lesion-outcome effects in the left-dominant language network that highlight the ventral pathway as a core lesion focus across different tests of language performance. We provide detailed evidence for sex-specific brain-behavior associations in the domain-general networks associated with cortico-subcortical pathways, with unique contributions of the fornix in women and cingular fiber bundles in men. Our collective findings suggest diverging white matter substrates in how stroke causes language deficits in women and men. Clinically acknowledging such sex disparities has the potential to improve personalized treatment for stroke patients worldwide.
... In addition to aging effects, differences between men and women in language processing have been a topic of major interest (Wallentin, 2009). Although anatomical differences between the linguistic cortex of men and women have been found, for example, larger superior temporal volumes in women compared to men (Sowell et al., 2007), these findings should be interpreted with caution since men show greater variance in brain structures than women across their entire lifespan (Wierenga et al., 2022). ...
Purpose
The clinical use of event-related potentials in patients with language disorders is increasingly acknowledged. For this purpose, normative data should be available. Within this context, healthy aging and gender effects on the electrophysiological correlates of semantic sentence comprehension were investigated.
Method
One hundred and ten healthy subjects (55 men and 55 women), divided among three age groups (young, middle aged, and elderly), performed a semantic sentence congruity task in the visual modality during electroencephalographic recording.
Results
The early visual complex was affected by increasing age as shown by smaller P2 amplitudes in the elderly compared to the young. Moreover, the N400 effect in the elderly was smaller than in the young and was delayed compared to latency measures in both middle-aged and young subjects. The topography of age-related amplitude changes of the N400 effect appeared to be gender specific. The late positive complex effect was increased at frontal electrode sites from middle age on, but this was not statistically significant. No gender effects were detected regarding the early P1, N1, and P2, or the late positive complex effect.
Conclusion
Especially aging effects were found during semantic sentence comprehension, and this from the level of perceptual processing on. Normative data are now available for clinical use.
... Женщины лучше различают фонемы и легче запоминают слова, причем половые различия по этому признаку наблюдаются с 5-летнего возраста [Kaushanskaya et al., 2011[Kaushanskaya et al., , 2013. Женщины быстрее, чем мужчины, подбирают нужные слова, находят синонимы и антонимы и лучше выполняют задания, требующие словарной гибкости, например, находят больше слов, начинающихся с названной буквы или относящихся к определенной категории [Hyde, 1988;Bauer et al., 2002;Larsson et al., 2003;Maitland et al., 2004;Wallentin, 2009;Eriksson et al., 2012]. На основании некоторых экспериментальных данных можно предположить, что в данном случае в основе половых различий лежат различия в скорости и стиле обработки информации, в частности группировка объектов по семантическим признакам, более свойственная женщинам, чем мужчинам [Ullman,2004;Ullman et al., 2008;Yılmaz, 2010;Li, 2014]. ...
Анализировались половые различия в академических достижениях, которые оценивались по результатам выполнения заданий Единого государственного экзамена в 2010–2012 гг. Выборка исследования включает 11160 пар близнецов и репрезентативна популяции близнецов соответствующего возраста, проживающих на территории России. Для определения половых различий оценивались различия средних, дисперсий и величина эффекта d (разница в средних баллах мальчиков и девочек, деленная на усредненное по группам мальчиков и девочек стандартное отклонение). Основные результаты исследования: в академической успеваемости по большинству школьных предметов, по которым ученики сдают ЕГЭ, наблюдаются половые различия. Значимые половые различия обнаруживаются по следующим дисциплинам: математике, русскому языку, иностранному(английскому) языку, истории, литературе, биологии, обществознанию. Отсутствуют различия между юношами и девушками в успешности выполнения заданий ЕГЭ по физике, химии, географии и информатике. В тех случаях, когда имеются значимые различия в успеваемости по предмету, успешнее сдают экзамен девочки. Исключение составляет лишь одна школьная дисциплина – математика. По математике мальчики превосходят девочек в академической успешности при анализе данных по всей выборке, отставая от девочек в подгруппе потенциальных абитуриентов вузов физико-математического направления.
... Bangladesh [36,37], Nepal [9] and India [39]. This may be due to biological factors [54] although other studies did not support it [55]. So, additional research is important to see how sex differences arise due to the in uence of sex hormones at different developmental stages, which may lead to differences in various language task performance. ...
Background
Children’s growth and development are multifactorial. Little is known about the maternal and children’s factors associated with children’s development and growth in urban areas of low- and middle-income countries. The objective of this study was to determine the important factors associated with children’s development (cognitive, language and motor) and growth (length for age Z score) at age 6–16 months
Methods
This cross-sectional study was conducted in an urban area of Bangladesh. Bayley III and the WHO methods were used to assess children’s development and growth respectively. Multivariable linear regression model and dominance analysis were used to determine the important factors associated with development and growth.
Results
Out of the total 599 mother-child dyads, 303 (50.58%) were girls. The common determinants of children’s development were Length-for-age-Z-score (LAZ) [cognitive: B = 1.21 (95%CI = 0.31, 2.11), P = 0.008, Language: 1.67 (0.79, 2.55) P < 0.001; motor: 2.15 (1.01, 3.29) P < 0.001] and home environment [cognitive: 0.58 (0.27, 0.89) P < 0.001, Language: 0.59 (0.27, 0.92), P < 0.001, motor: 0.44 (0.09, 0.79) P = 0.013]. Girls had higher cognitive and language development and LAZ scores than the boys. LAZ score was predicted by their age and gender and the children of families with middle wealth quintile were taller than the children of lower wealth quintile.
Conclusion
Children’s nutritional status and home environment are important factors for children’s development in low resource urban settings of Bangladesh. Poverty is an important predictor of children’s growth.
... This clearly involves comprehension and some aspect of logical reasoning both of which are not needed for the Stroop task. In a review article, Wallentin (2009) noted that the verbal fluency task is perhaps the most cited verbal ability procedure that has yielded sex differences (e.g., Sommer et al., 2004). In the standard version of the task, participants are required to generate as many words as they can from a particular category (e.g., animals), or beginning with a certain letter, within a given time (e.g., five minutes). ...
Previous research shows that women outperform men in the classic Stroop task, but it is not known why this difference occurs. There are currently two main hypotheses: (1) women have enhanced verbal abilities, and (2) women show greater inhibition. In two Stroop experiments, we examined the Inhibition hypothesis by adopting a procedure, often used in visual cognition paradigms, that induces a particular inhibitory component. So-called Negative Priming occurs when a distracting non-target stimulus on one trial becomes the target on the following trial. Results from our experiments showed that the degree to which this type of inhibition occurs within the Stroop effect is no different for men and women. This was the case irrespective of whether participants made a vocal response (Experiment 1; n = 64, 32 men and 32 women) or a manual response (Experiment 2; n = 64, 32 men and 32 women). These results do not therefore support the Inhibition hypothesis. We additionally review findings from a range of paradigms that can be seen as indexing the different components required for the Stroop task (e.g., distractor suppression). This review suggests that the sex effect is due to superior color naming ability in women.
The Manual section of the Handbook of Pragmatics, produced under the auspices of the International Pragmatics Association (IPrA), is a collection of articles describing traditions, methods, and notational systems relevant to the field of linguistic pragmatics; the main body of the Handbook contains all topical articles. The first edition of the Manual was published in 1995. This second edition includes a large number of new traditions and methods articles from the 24 annual installments of the Handbook that have been published so far. It also includes revised versions of some of the entries in the first edition. In addition, a cumulative index provides cross-references to related topical entries in the annual installments of the Handbook and the Handbook of Pragmatics Online (at https://benjamins.com/online/hop/), which continues to be updated and expanded. This second edition of the Manual is intended to facilitate access to the most comprehensive resource available today for any scholar interested in pragmatics as defined by the International Pragmatics Association: “the science of language use, in its widest interdisciplinary sense as a functional (i.e. cognitive, social, and cultural) perspective on language and communication.”
Girls tend to outperform boys in language development and literacy, but the reasons behind this remain unclear, particularly whether the family environment plays a role. This study examines gender differences in parental linguistic engagement and its effect on language outcomes. Using data from the French birth cohort Elfe (ranging from 14,000 children for early outcomes to 4000 for later outcomes), parental questionnaires assessed linguistic engagement from ages 1 to 5. Children's language outcomes were measured via the McArthur-Bates CDI at age 2, and language and literacy tests in preschool and first grade. Analyses showed that parents engaged more with girls than boys (standardized β = 0.10 to 0.17), and this engagement partially mediated the relationship between sex and language outcomes (mediation 6 % to 19 %). These findings suggest that parental language engagement contributes to sex differences in language development, with implications for designing interventions that ensure equitable language opportunities for all children.
Introduction
Children's early language and communication skills are efficiently measured using parent report, for example, communicative development inventories (CDIs). These have scalable potential to determine risk of later language delay, and associations between delay and risk factors such as prematurity and poverty. However, there may be measurement difficulties in parent reports, including anomalous directions of association between child age/socioeconomic status and reported language. Findings vary on whether parents may report older infants as having smaller vocabularies than younger infants, for example.
Methods
We analysed data from the UK Communicative Development Inventory (Words and Gestures); UK‐CDI (W&G) to determine whether anomalous associations would be replicated in this population, and/or with gesture. In total 1204 families of children aged 8–18 months (598 girls, matched to UK population for income, parental education and ethnicity as far as possible) completed Vocabulary and Gesture scales of the UK‐CDI (W&G).
Results
Overall scores on the Gesture scale showed more significant relationships with biological risk factors including prematurity than did Vocabulary scores. Gesture also showed more straightforward relationships with social risk factors including income. Relationships between vocabulary and social risk factors were less straightforward; some at‐risk groups reported higher vocabulary scores than other groups.
Discussion
We conclude that vocabulary report may be less accurate than gesture for this age. Parents have greater knowledge of language than gesture milestones, hence may report expectations for vocabulary, not observed vocabulary. We also conclude that gesture should be included in early language scales partly because of its greater, more straightforward association with many risk factors for language delay.
WHAT THIS PAPER ADDS
What is already known on the subject
We already know that it is possible to measure children's early communicative skills using parent‐completed inventories (Communicative Development Inventories, CDIs) and that some aspects of early communication can predict which children are likely to go on to have long‐lasting communicative development difficulties. We also know that most uses of CDIs include only vocabulary, not early gesture. In addition, child‐related and family‐related variables such as prematurity, family history of language disorder and socioeconomic status may be related to communication development.
What this paper adds to existing knowledge
We looked at a large sample ( N = approx. 1200) of families representative of the UK population with an infant aged 8 through 18 months and asked them about their infant's comprehension and production vocabulary as well as their early gesture skills. Gesture was more closely related to possible risk factors for communication development difficulties, for example, family history of communication difficulties, prematurity and multiple birth status. Vocabulary was only related in a straightforward way to family history and had complex relationships to socioeconomic differences. Families with different economic backgrounds may approach questions about their child's development in different ways.
What are the potential or actual clinical implications of this work?
We suggest that clinicians need to ensure that not only vocabulary but also gesture ability is assessed when looking at very early communication skills. We also suggest that gesture may be more predictive of later communicative development difficulties, and that clinicians need to be sure that parents are clear on how vocabulary questions are asked and what exactly is required of them in answering these types of questions.
Numerous studies reported inconsistent results concerning gender influences on the functional organization of the brain for language in children and adults. However, data for the gender differences in the functional language networks at birth are sparse. Therefore, we investigated gender differences in resting-state functional connectivity in the language-related brain regions in newborns using functional near-infrared spectroscopy. The results revealed that female newborns demonstrated significantly stronger functional connectivities between the superior temporal gyri and middle temporal gyri, the superior temporal gyri and the Broca’s area in the right hemisphere, as well as between the right superior temporal gyri and left Broca’s area. Nevertheless, statistical analysis failed to reveal functional lateralization of the language-related brain areas in resting state in both groups. Together, these results suggest that the onset of language system might start earlier in females, because stronger functional connectivities in the right brain in female neonates were probably shaped by the processing of prosodic information, which mainly constitutes newborns’ first experiences of speech in the womb. More exposure to segmental information after birth may lead to strengthened functional connectivities in the language system in both groups, resulting in a stronger leftward lateralization in males and a more balanced or leftward dominance in females.
This study investigates the effects of gender and the learning context on learners’ perceptions of Arabic consonant contrasts. To this end, 60 intermediate Arabic learners, half of which were males and half of which were females, were recruited from two different learning contexts: a study-abroad (SA) program in Egypt and an at-home (AH) setting at a western American university. Learners in the two groups were tested before and after a semester of Arabic study using a perception task that involved distinguishing four Arabic consonant contrasts: /d - dˁ/, /h - ħ/, /s - sˁ/, and /t - tˁ/). The results reveal that the advantage of females in segmental identification accuracy was not verified, as female performance did not significantly differ from male performance in any of the four target consonant contrasts. In contrast, the learning context was found to positively impact learners’ perceptions of the target Arabic consonants, as the SA group significantly outperformed their counterparts in the AH environment on the /h - ħ/ and /d - dˁ/ contrasts. However, there were no significant differences between learners in the two different contexts regarding the two other consonant contrasts (i.e., /s - sˁ/ and /t - tˁ/). The findings bring insights into the understanding of the gender-based differences in identifying problematic Arabic consonantal contrasts for English learners in two different contexts of learning, and they shed light on the implications for language pedagogy for pronunciation training.
Background and Purpose: In the dichotic listening test, not only the asymmetry of the auditory system is evaluated but also the associated cognitive processes. The aim of this study was to examine the effect of male and female voices on dichotic listening. Methods: Participants consisted of 10 men and 14 women, aged 18–45 (28.54±6.23) without neurological or auditory disorders. The dichotic listening test was applied to four different sessions. These sessions: female voices in both ears, male voices in both ears, male and female voices in both ears (mono session), male voices in the right ear, female voices in the left ear, and female voices in the right ear, and male voices in the left ear (stereo). Results: It was determined that brain lateralization was significantly reduced in the female session compared with the stereo session; in other words, right ear dominance decreased (p=0.026, d=-0.293). It was determined that there was a significant difference between the number of errors in male and stereo sessions. Conclusion: Participants preferred the syllables voiced with male voice more in mono and stereo sessions. It is observed that female participants mostly prefer syllables voiced with a male voice, and male participants prefer syllables voiced with a female voice.
Background
Sexually polymorphic cognition (SPC) results from the interaction between biological (birth-assigned sex (BAS), sex hormones) and socio-cultural (gender identity, gender roles, sexual orientation) factors. The literature remains quite mixed regarding the magnitude of the effects of these variables. This project used a battery of classic cognitive tests designed to assess the influence of sex hormones on cognitive performance. At the same time, we aimed to assess the inter-related and respective effects that BAS, sex hormones, and gender-related factors have on SPC.
Methods
We recruited 222 adults who completed eight cognitive tasks that assessed a variety of cognitive domains during a 150-min session. Subgroups were separated based on gender identity and sexual orientation and recruited as follows: cisgender heterosexual men ( n = 46), cisgender non-heterosexual men ( n = 36), cisgender heterosexual women ( n = 36), cisgender non-heterosexual women ( n = 38), gender diverse ( n = 66). Saliva samples were collected before, during, and after the test to assess testosterone, estradiol, progesterone, cortisol, and dehydroepiandrosterone. Psychosocial variables were derived from self-report questionnaires.
Results
Cognitive performance reflects sex and gender differences that are partially consistent with the literature. Interestingly, biological factors seem to better explain differences in male-typed cognitive tasks (i.e., spatial), while psychosocial factors seem to better explain differences in female-typed cognitive tasks (i.e., verbal).
Conclusion
Our results establish a better comprehension of SPC over and above the effects of BAS as a binary variable. We highlight the importance of treating sex as a biological factor and gender as a socio-cultural factor together since they collectively influence SPC.
Sex/gender differences in cognitive sciences are riddled by conflicting perspectives. At the center of debates are clinical, social, and political perspectives. Front and center, evolutionary and biological perspectives have often focused on 'nature' arguments, while feminist and constructivist views have often focused on 'nurture arguments regarding cognitive sex differences. In the current narrative review, we provide a comprehensive overview regarding the origins and historical advancement of these debates while providing a summary of the results in the field of sexually polymorphic cognition. In so doing, we attempt to highlight the importance of using transdisciplinary perspectives which help bridge disciplines together to provide a refined understanding the specific factors that drive sex differences a gender diversity in cognitive abilities. To summarize, biological sex (e.g., birth-assigned sex, sex hormones), socio-cultural gender (gender identity, gender roles), and sexual orientation each uniquely shape the cognitive abilities reviewed. To date, however, few studies integrate these sex and gender factors together to better understand individual differences in cognitive functioning. This has potential benefits if a broader understanding of sex and gender factors are systematically measured when researching and treating numerous conditions where cognition is altered.
Language refers to the uniquely human capacity for communication through the productive combination of meaningful symbols. Functional neuroimaging studies have greatly expanded our knowledge of the brain systems supporting language, producing a dramatic reawakening of interest in this topic and substantial revision of the classical neuroanatomical model formulated by Broca, Wernicke, and others. This chapter discusses key theoretical issues regarding functional imaging of language systems and describes several mapping paradigms in common clinical use. Research on the reliability and validity of functional magnetic resonance imaging (fMRI) language mapping is reviewed, and clinical applications are presented with several example cases. A central theme is that interpretation of fMRI language studies depends on an informed analysis of the cognitive processes engaged during scanning. This analytic approach can help avoid common pitfalls in task design that limit the sensitivity and specificity of language mapping studies and should encourage the development of a standardized methodological and conceptual framework for such studies.KeywordsLanguageBrain mappingFunctional magnetic resonance imagingPresurgical mappingLateralization
Differences between the two genders are widespread in nature (Fig. 17.1) and concern a variety of characteristics, including not only the external appearance but also inclinations and skills, as well as the way of thinking and the overall behavior.
The objective of this study is to characterize writing samples in Catalan written by boys and girls in primary school (from seven to 12 years old) using syntactic patterns. The corpus contains 169 writings divided by sex (76 boys and 93 girls) with an average of 200 words and a total length of 33,763 words. From this corpus, we calculated the 40 n-grams of the most frequent morphological categories (bigrams, trigrams). The data were statistically analysed using ANOVA and Linear Discriminant Analysis, and the accuracy in predicting the writer’s gender in a cross-validation experiment was 60.4% using both bigrams and trigrams. When the children’s age was taken into account, the percentage of accuracy was higher than 70% in both the original classification and the cross-validation. The identification of the most discriminating bigrams and trigrams allowed us to determine that girls show a greater expressive capacity and superior syntactic maturity, and greater lexical and syntactic richness.
Normative data stratified by three levels of age (16–59, 60–79, and 80–95 years) and three levels of education (0–8, 9–12, and 13–21 years) are presented for phonemic verbal fluency (FAS) and categorical verbal fluency (Animal Naming). The normative sample, aged 16 to 95 years, consisted of 1,300 cognitively intact individuals who resided in the community. Years of education ranged from 0 to 21. The total number of words in 1 minute for each of the letters F, A, and S was correlated r = .52 with the number of animal names generated in 1 minute. Regression analyses showed that FAS was more sensitive to the effects of education (18.6% of the variance) than age (11.0% of the variance). The opposite relationship occurred for Animal Naming, where age accounted for 23.4% of the variance and education accounted only for 13.6%. Gender accounted for less than 1% of variance for FAS and Animal Naming. The clinical utility of these norms is discussed.
The mating mind' revives and extends Darwin's suggestion that sexual selection through mate choice was important in human mental evolution - especially the more 'self-expressive' aspects of human behavior, such as art, morality, language, and creativity. Their 'survival value' has proven elusive, but their adaptive design features suggest they evolved through mutual mate choice, in both sexes, to advertise intelligence, creativity, moral character, and heritable fitness. The supporting evidence includes human mate preferences, courtship behavior, behavior genetics, psychometrics, and life history patterns. The theory makes many testable predictions, and sheds new light on human cognition, motivation, communication, sexuality, and culture.
Located 165 studies that reported data on gender differences in verbal ability. The weighted mean effect size was +0.11, indicating a slight female superiority in performance. The difference is so small that we argue that gender differences in verbal ability no longer exist. Analysis of tests requiring different cognitive processes involved in verbal ability yielded no evidence of substantial gender differences in any aspect of processing. Similarly, an analysis of age indicated no striking changes in the magnitude of gender differences at different ages, countering Maccoby and Jacklin's (1974) conclusion that gender differences in verbal ability emerge around age 11 yrs. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
For any given research area, one cannot tell how many studies have been conducted but never reported. The extreme view of the "file drawer problem" is that journals are filled with the 5% of the studies that show Type I errors, while the file drawers are filled with the 95% of the studies that show nonsignificant results. Quantitative procedures for computing the tolerance for filed and future null results are reported and illustrated, and the implications are discussed. (15 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The present study of over 3000 2-year-old twin pairs used a sex-limitation model to examine genetic and environmental origins of sex differences in verbal and non-verbal cognitive ability. Girls scored significantly higher on both measures (p<0.0001), although gender only accounted for approximately 3% of the variance in verbal ability and 1% of the variance in non-verbal cognitive ability. For the verbal measure boys showed greater heritability than girls. Also the twin-pair correlation is significantly lower for opposite-sex twins than for non-identical same-sex twins. This indicates that individual differences in verbal ability include some sex-specific factors. Non-verbal cognitive ability did not differ in aetiology for boys and girls. We conclude that genetic and environmental influences differ for girls and boys for early verbal but not non-verbal development.
To investigate possible gender differences in the patterns of age-cognition relations, a meta-analysis was conducted on the
data from 25 studies (5,201 participants) by the second author and his collaborators. Gender and age differences consistent
with prior reports were found, but there were few measures on which the age × gender interactions were significant. Although
the majority of neuroimaging studies investigating gender differences in age-related atrophy and functional decline report
greater age-related differences in males, the only significant interactions on the cognitive measures in this study (on measures
of speed and reasoning) were in the direction of lesser age-related declines for males than for females.
Our knowledge about the variability of cerebral language lateralization is derived from studies of patients with brain lesions and thus possible secondary reorganization of cerebral functions. In healthy right-handed subjects 'atypical', i.e. right hemisphere language dominance, has generally been assumed to be exceedingly rare. To test this assumption we measured language lateralization in 188 healthy subjects with moderate and strong right-handedness (59% females) by a new non-invasive, quantitative technique previously validated by direct comparison with the intracarotid amobarbital procedure. During a word generation task the averaged hemispheric perfusion differences within the territories of the middle cerebral arteries were determined. (i) The natural distribution of language lateralization was found to occur along a bimodal continuum. (ii) Lateralization was equivalent in men and women. (iii) Right hemisphere dominance was found in 7.5% of subjects. These findings indicate that atypical language dominance in healthy right-handed subjects of either sex is considerably more common than previously suspected.
The purpose of this study was to assess the nonspeech behaviors associated with young stutterers’ stuttering and normally fluent children’s comparable fluent utterances. Subjects were 28 boys and 2 girls who stutter (mean age=54 months) and 28 boys and 2 girls who do not stutter (mean age=54 months). Each child and his or her mother were audio-video recorded during a loosely structured, 30-min conversation. Sixty-six different nonspeech behaviors associated with 10 randomly selected stutterings per stutterer and 10 comparable fluent utterances per normally fluent child were assessed by means of frame-by-frame analysis of the audio-video recordings. Results indicate that (a) young stutterers produce significantly more nonspeech behaviors during stuttered words than do normally fluent children during comparable fluent words, (b) young stutterers produce significantly more head turns left, blinks, and upper lip raising during stuttered words than do normally fluent children during comparable fluent words, and (c) talker group membership could be significantly determined on the basis of certain types of nonspeech behaviors despite considerable overlap in frequency and type of nonspeech behavior between the two talker groups. Findings suggest that children can be classified as stutterers on the basis of their nonspeech behaviors and that these behaviors may reflect a variety of cognitive, emotional, linguistic, and physical events associated with childhood stuttering.
The sexual dimorphism of the corpus callosum has remained controversial since the original report by de Lacoste-Utamsing and Holloway in 1982, for several reasons: (1) measurements have been performed in a variety of ways in different laboratories, in part because published reports frequently do not describe the methodology in detail; (2) despite known age-related changes during both childhood and adulthood, no investigators have explicitly age-matched subjects; and (3) the size and shape of corpora callosa vary considerably among individuals, requiring large sample sizes to demonstrate significant sex differences. Therefore, we have examined magnetic resonance images for 24 age-matched children and 122 age-matched adults for possible sex differences in the corpus callosum. While we observed a dramatic sex difference in the shape of the corpus callosum, there was no conclusive evidence of sexual dimorphism in the area of the corpus callosum or its subdivisions. Utilizing several criteria, there were significant sex differences in shape: subjective evaluation indicated that the posterior region of the corpus callosum, the splenium, was more bulbous shaped in females as a group and in women, and more tubular-shaped in males as a group and in men; mathematical evaluation confirmed this observation in that the maximum width of the splenium was significantly greater in women than in men, and that the percentage by which the average width of the splenium was greater than that of the adjacent corpus callosum was significantly greater in females than in males. However, sex differences in bulbosity did not reach significance in children (aged 2-16 yr). In contrast, among the area measurements of the corpus callosum and 22 subdivisions, only 1 exhibited a significant sex difference, which would be expected by chance. The area of the corpora callosa increased significantly with age in children and decreased significantly with age in adults. In adults, the midsagittal surface area of the cerebral cortex decreased significantly with age in women but not in men. These anatomical sex differences could, in part, underlie gender-related differences in behavior and neuropsychological function.
Controversy exists in the neuropsychological literature concerning the existence of gender-associated differences in cognitive functioning and in hemispheric lateralization of cognitive functions. A recent study, based on 14 brains obtained at autopsy, reported sex differences in the splenium of the human corpus callosum and suggested that the larger splenium in females reflects less hemispheric lateralization, or "specialization," than the male brain for visuospatial functions. Our measurements of the human corpus callosum using magnetic resonance images of 37 living subjects failed to confirm reported sex differences in the splenium. A marginally significant sex-related difference in minimum body width and an age-related decrease in anteroposterior distance were found. Most striking were the large variations in callosal size and shape among individuals regardless of age or gender. Existing knowledge of the functions of the corpus callosum does not permit correlations between variations in callosal size and shape and variations in cognitive functions.
12 male and 12 female right-handed adults performed a unimanual force-production task alone and while sound-shadowing high frequency words. The secondary speech task disrupted right-hand performance by men and left-hand performance by women. The implications of these findings for intrahemisphere-interference models of dual-task performance are discussed.
A retrospective study on incidence of aphasia and apraxia was done on 143 male (mean age 50.4 yrs) and 73 female (mean age 45.7 yrs) right-handed patients with unilateral lesions of the left cerebral hemisphere and on a subgroup of 81 patients with damage restricted to anterior or posterior regions. Aphasia was proportionally more frequent in males than in females, but this difference was significant only in the larger sample. Moreover, the pattern of speech representation differed between the sexes: Speech disorders and manual apraxia occurred in females more often from damage to the anterior part of the left hemisphere than from posterior damage. This was not true for males. In the 169 Ss with unilateral right-hemisphere damage, the incidence of aphasia was extremely low and did not differentiate the sexes. It is concluded that there are sex differences in the organization of speech and praxis within the left hemisphere and that speech is not simply more bilaterally organized in females than males. (French abstract) (29 ref)
Stuttering is not usually considered genetic, although it has long been known to be familial. Data collected on 2035 relatives of 397 unrelated adult stutterers confirm and quantify the strong familial concentration. Our analytic approach to these family data, one that does not require specification of a genetic hypothesis, shows that stuttering among relatives occurs in a pattern indicating vertical transmission of a susceptibility to stuttering with sex-modified expression. Although simple Mendelian hypotheses are not sufficient to explain the observed pattern of stuttering in families, more complex genetic models can explain the pattern. In the past, such evidence has been considered sufficient, because it does not preclude the possibility of cultural transmission. However, certain cultural transmission hypotheses previously proposed for stuttering are excluded by these data. The findings in this study support a growing opinion among speech pathologists that most stuttering is a genetically inherited neurologic disorder.
Preliminary observations suggest a sex difference in the shape and surface area of the human corpus callosum. The sexual dimorphism is striking in the splenium, the caudal or posterior portion of the corpus callosum. The female splenium is both more bulbous and larger than the male counterpart. Since peristriate, parietal, and superior temporal fibers course through the splenium, this finding could be related to possible gender differences in the degree of lateralization for visuospatial functions.
The role of genetic factors in the etiology of stuttering was investigated in 30 pairs of same-sex twins, each pair containing at least one stutterer. Care was taken to ensure maximum accuracy in zygosity classification and objectivity in stuttering diagnosis. Zygosity classification was made independently of stuttering diagnosis. Pair-wise concordance for stuttering was significantly higher in identical twins (63%) than in fraternal same-sex twins (19%). The estimated risk of stuttering in the monozygotic (MZ) co-twin of a stutterer was .77, and .32 in the dizygotic (DZ) co-twin of a stutterer, The findings strongly suggest the operation of genetic factors in stuttering, However, the presence of as many as six pairs of identical twins who were discordant for stuttering underlines the importance of the interaction of genetic and environmental factors in the etiology of this disorder.
In an age where the amount of data collected from brain imaging is increasing constantly, it is of critical importance to analyse those data within an accepted framework to ensure proper integration and comparison of the information collected. This book describes the ideas and procedures that underlie the analysis of signals produced by the brain. The aim is to understand how the brain works, in terms of its functional architecture and dynamics. This book provides the background and methodology for the analysis of all types of brain imaging data, from functional magnetic resonance imaging to magnetoencephalography. Critically,Statistical Parametric Mappingprovides a widely accepted conceptual framework which allows treatment of all these different modalities. This rests on an understanding of the brain's functional anatomy and the way that measured signals are caused experimentally. The book takes the reader from the basic concepts underlying the analysis of neuroimaging data to cutting edge approaches that would be difficult to find in any other source. Critically, the material is presented in an incremental way so that the reader can understand the precedents for each new development. This book will be particularly useful to neuroscientists engaged in any form of brain mapping; who have to contend with the real-world problems of data analysis and understanding the techniques they are using. It is primarily a scientific treatment and a didactic introduction to the analysis of brain imaging data. It can be used as both a textbook for students and scientists starting to use the techniques, as well as a reference for practicing neuroscientists. The book also serves as a companion to the software packages that have been developed for brain imaging data analysis. * An essential reference and companion for users of the SPM software * Provides a complete description of the concepts and procedures entailed by the analysis of brain images * Offers full didactic treatment of the basic mathematics behind the analysis of brain imaging data * Stands as a compendium of all the advances in neuroimaging data analysis over the past decade * Adopts an easy to understand and incremental approach that takes the reader from basic statistics to state of the art approaches such as Variational Bayes * Structured treatment of data analysis issues that links different modalities and models * Includes a series of appendices and tutorial-style chapters that makes even the most sophisticated approaches accessible.
Modern stereological methods provide precise and reliable estimates of the number of neurons in specific regions of the brain. We decided to estimate the total number of neocortical neurons in the normal human brain and to analyze it with respect to the major macro- and microscopical structural components, to study the internal relationships of these components, and to quantitate the influence of important physiological variables on brain structure. The 94 brains reported represent a consecutive collection of brains from the general Danish population. The average numbers of neocortical neurons were 19 billion in female brains and 23 billion in male brains, a 16% difference. In our study, which covered the age range from 20 years to 90 years, approximately 10% of all neocortical neurons are lost over the life span in both sexes. Sex and age were the main determinants of the total number of neurons in the human neocortex, whereas body size, per se, had no influence on neuron number. Some of the data presented have been analyzed by using new mathematical designs. An equation predicting the total neocortical neuron number in any individual in which sex and age are known is provided.
At its simplest, voxel-based morphometry (VBM) involves a voxelwise comparison of regional gray matter 'density' between two groups of subjects. Density here refers to the relative amount of gray matter and should not be confused with cell packing density (number of cells per unit volume of neuropil). The procedure is relatively straightforward and involves spatially normalizing and segmenting high-resolution magnetic resonance images into the same stereotaxic space. These gray matter segments are then smoothed to a spatial scale at which differences are expressed (usually approximately 8. mm). Voxelwise parametric statistical tests are performed, which compare the smoothed gray matter images from the groups using statistical parametric mapping. Corrections for multiple comparisons are generally made using the theory of random fields.
Objective:
To comprehensively and critically review the literature on gender differences in schizophrenia.
Method:
An initial search of MEDLINE abstracts (1966-1999) was conducted using the terms sex or gender and schizophrenia, followed by systematic search of all relevant articles.
Results:
Males have consistently an earlier onset, poorer premorbid functioning and different premorbid behavioral predictors. Males show more negative symptoms and cognitive deficits, with greater structural brain and neurophysiological abnormalities. Females display more affective symptoms, auditory hallucinations and persecutory delusions with more rapid and greater responsivity to antipsychotics in the premenopausal period but increased side effects. Course of illness is more favorable in females in the short- and middle-term, with less smoking and substance abuse. Families of males are more critical, and expressed emotion has a greater negative impact on males. There are no clear sex differences in family history, obstetric complications, minor physical anomalies and neurological soft signs.
Conclusion:
This review supports the presence of significant differences between schizophrenic males and females arising from the interplay of sex hormones, neurodevelopmental and psychosocial sex differences.
Language dominance and factors that influence language lateralization were investigated in right-handed, neurologically normal subjects ( n = 100) and right-handed epilepsy patients ( n = 50) using functional MRI. Increases in blood oxygenation-dependent signal during a semantic language activation task relative to a non-linguistic, auditory discrimination task provided an index of language system lateralization. As expected, the majority of both groups showed left hemisphere dominance, although a continuum of activation asymmetry was evident, with nearly all subjects showing some degree of right hemisphere activation. Using a categorical dominance classification, 94% of the normal subjects were considered left hemisphere dominant and 6% had bilateral, roughly symmetric language representation. None of the normal subjects had rightward dominance. There was greater variability of language dominance in the epilepsy group, with 78% showing left hemisphere dominance, 16% showing a symmetric pattern and 6% showing right hemisphere dominance. Atypical language dominance in the epilepsy group was associated with an earlier age of brain injury and with weaker right hand dominance. Language lateralization in the normal group was weakly related to age, but was not significantly related to sex, education, task performance or familial left-handedness.
This paper reviews the literature on prognostic factors related to recovery from aphasia. These can be regrouped under two headings: anagraphical and neurological factors. Age, sex and handedness are the anagraphical factors considered. Aetiology, site and extent of lesion, and severity and type of aphasia are the neurological ones. The effects of aphasia therapy are considered separately in more detail. Finally, the literature on patterns of recovery in groups of patients and in individual patients is reviewed. It is concluded that personal factors (age, sex, handedness) play a minor role in recovery from aphasia. Initial severity of aphasia and rehabilitation are the most important factors.
As outlined in prior chapters, gonadal hormones have powerful influences on sexual differentiation of brain and behavior in a wide range of mammals. This raises the question of whether sex differences in hu-man behavior could result in part from similar hor-monal influences. Human behavioral sex differences are currently understood to result from a combina-tion of social, cultural, cognitive, and biological mech-anisms (e.g., Golombok and Fivush, 1994). However, this work is about hormones. In keeping with this, this chapter will focus on one particular aspect of biological influences, the role of gonadal hormones, particularly androgens and estrogens, in the development of hu-man behaviors and human brain structures that show sex differences. Before beginning the review, it will be helpful to de-fine several terms and to outline the theoretical models that have been proposed to explain hormonal influ-ences on sexual differentiation in other species. (Al-though this will provide an overview of relevant an-imal models, other chapters of this work treat these models in greater detail, and interested readers are re-ferred to them for more extensive information.) After the overview of animal models, information about hu-man situations involving hormonal abnormalities will be described, as will the human behaviors that show sex differences and would therefore be hypothesized to be influenced by gonadal hormones. Finally, data on sex-ually differentiated behaviors in humans with hormone abnormalities will be discussed and conclusions as to the extent, nature, and implications of hormonal influ-ences on human sexual differentiation will be drawn.
This is a book about speech and language. it is primarily intended for those interested in speech and its neurophysiological bases: phoneticians, linguists, educators, speech therapists, psychologists and neuroscientists. Although speech and language are its central topics, it provides information about related topics as well (e.g. structure and functioning of the central nervous system, research methods in neuroscience, theories and models of speech production and perception, learning and memory). Data on clinical population are given in parallel with studies of healthy subjects because such comparisons can give a better understanding of intact and disordered speech and language functions.
There is a review of literature (more than 600 sources) and research results covering areas such as neuroanatomy, neurophysiology, development of the nervous system, sex differences, history of neurolinguistics, behavioral, neuroimaging and other research methods in neuroscience, linguistics and psychology, theories and models of the nervous system function including speech and language processing, kinds of memory and learning and their neural substrates, critical periods, various aspects of normal speech and language processes (e.g. phonetics, phonology, syntax, semantics, reading), bilingualism, speech and language disorders, and many others. A comprehensive glossary provides additional information.
Altogether 329 children participated in four longitudinal studies of specific and general language performance cumulatively from 1;1 to 6;10. Data were drawn from age-appropriate maternal questionnaires, maternal interviews, teacher reports, experimenter assessments and transcripts of children’s own spontaneous speech. Language performance at each age and stability of individual differences across age in girls and boys were assessed separately and together. Across age, including the important transition from preschool to school, across multiple tests at each age and across multiple reporters, children showed moderate to strong stability of individual differences; girls and boys alike were stable. In the second through fifth years, but not before or after, girls consistently outperformed boys in multiple specific and general measures of language.
Although sex differences in cognitive abilities have been reported in the experimental literature, there has been a paucity of information about how men and women might perform differently on clinical neuropsychological tests. The present study examines sex differences in verbal learning. Sixtyeight men and 68 women of equal age and education were administered the California Verbal Learning Test. Dependent variables included measures of recall, recognition, learning characteristics, and error types. Women displayed consistently higher levels of immedite and delayed free recall and made greater use of semantic clustering. There were no sex differences on recognition testing or error types. Results suggest that women's superior recall is attributable to better retrieval, which, in turn, is related to their greater use of verbally mediated strategies. This study highlights the importance of investigating sex differences on clinical instruments and reporting separate sex norms when appropriate.
Females and males show different average patterns of academic achievement and scores on cognitive ability tests. Females obtain higher grades in school, score much higher on tests of writing and content-area tests on which the questions are similar to material that was learned in school, attain a majority of college degrees, and are closing the gap in many careers that were traditionally male. By contrast, males score higher on standardized tests of mathematics and science that are not directly tied to their school curriculum, show a large advantage on visuospatial tests (especially those that involve judgments of velocity and navigation through three-dimensional space), and are much more knowledgeable about geography and politics. A cognitive-process taxonomy can shed light on these differences.
Evolutionary psychology is a relatively new paradigm and an interdisciplinary one that has engendered considerable debate, conflict and controversy among scholars of various disciplines. The purpose of this paper is to examine the sources of this conflict and to articulate the contested issues. Emerging from methodological and inferential differences among the relevant disciplines is the question of whether or not falsifiability need be a prerequisite for theories to be considered 'scientific.' Although universal consensus may substitute for falsifiability, the assumptions underlying the evolutionary psychology paradigm are neither falsifiable nor do they command universal consensus. Assumptions addressed in this paper include the nature of natural selection, the unit of selection, sources of variation, and the structure of the evolved human brain. Furthermore, the paradigm suffers from inherent contradictions: (a) the claim by evolutionary psychologists that knowledge of ultimate causes is necessary to accurately predict the consequences of proximate causes is contradicted when their hypotheses mimic those of learning theory; (b) when evolutionary psychologists conduct empirical research, results that contradict the paradigm are dismissed as invalid with the justification that current environments differ from ancestral ones; (c) although stating that data from non-human species are irrelevant, evolutionary psychologists utilize these data when convenient; (d) evolutionary psychologists acknowledge the role of ideology and politics in the formation and support of scientific paradigms but deny this influence in their own paradigm. Exacerbating the conflicts, some evolutionary psychologists present their paradigm as replacing, rather than coexisting with, current paradigms, alienating advocates of epistemological diversity. An alternative explanatory model is presented - one that is grounded in evolutionary theory, reflects recent advances in cognitive neuroscience and developmental psychology, and achieves a dialectical balance between nature and nurture.
Written for an introductory-level student audience, this text explores the biological basis of behavior, communicating the excitement of the tremendous advances in the field in recent years. Drawing on their teaching and research experiences, the authors organize this text around the key questions that intrigue brain researchers and students (i.e., "Why do we have a brain?" "How is the brain organized?"). A strong focus on clinical issues and innovative art is incorporated. A media and print supplements package is included. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Dual functional brain asymmetry refers to the notion that in most individuals the left cerebral hemisphere is specialized for language functions, whereas the right cerebral hemisphere is more important than the left for the perception, construction, and recall of stimuli that are difficult to verbalize. In the last twenty years there have been scattered reports of sex differences in degree of hemispheric specialization. This review provides a critical framework within which two related topics are discussed: Do meaningful sex differences in verbal or spatial cerebral lateralization exist? and, if so, Is the brain of one sex more symmetrically organized than the other? Data gathered on right-handed adults are examined from clinical studies of patients with unilateral brain lesions; from dichotic listening, tachistoscopic, and sensorimotor studies of functional asymmetries in non-brain-damaged subjects; from anatomical and electrophysiological investigations, as well as from the developmental literature. Retrospective and descriptive findings predominate over prospective and experimental methodologies. Nevertheless, there is an impressive accummulation of evidence suggesting that the male brain may be more asymmetrically organized than the female brain, both for verbal and nonverbal functions. These trends are rarely found in childhood but are often significant in the mature organism.
A cross-cohort PET analysis was performed in 62 normal subjects (31 men and 31 women) to address the issue of whether men and women have different physiologic correlates of naming visually presented concrete entities. The subjects named nonunique concrete entities in one or more conceptual categories and also performed a face orientation decision task. A second analysis was performed in 24 additional subjects to assess whether there were gender effects related to the face orientation decision task and to constrain the interpretation of the first analysis. Male subjects engaged the left inferotemporal region and several other left hemisphere regions more than female subjects did during visual naming. Areas showing more activity in female subjects included the right inferior frontal gyrus and right precentral cortex, regions that were less active in visual naming than in the face orientation decision task. In other words, the male subjects engaged the latter regions less or deactivated them more than female subjects. The results can be interpreted as showing a greater modulation of activity in both hemispheres for men compared to women. Although the gender effects we found are smaller than the task effects, they are not negligible for the purposes of performing and interpreting functional imaging studies.
Objective: To comprehensively and critically review the literature on gender differences in schizophrenia.
Method: An initial search of MEDLINE abstracts (1966–1999) was conducted using the terms sex or gender and schizophrenia, followed by systematic search of all relevant articles.
Results: Males have consistently an earlier onset, poorer premorbid functioning and different premorbid behavioral predictors. Males show more negative symptoms and cognitive deficits, with greater structural brain and neurophysiological abnormalities. Females display more affective symptoms, auditory hallucinations and persecutory delusions with more rapid and greater responsivity to antipsychotics in the pre-menopausal period but increased side effects. Course of illness is more favorable in females in the short- and middle-term, with less smoking and substance abuse. Families of males are more critical, and expressed emotion has a greater negative impact on males. There are no clear sex differences in family history, obstetric complications, minor physical anomalies and neurological soft signs.
Conclusion: This review supports the presence of significant differences between schizophrenic males and females arising from the interplay of sex hormones, neurodevelopmental and psychosocial sex differences.
This paper is based on a study carried out in Great Britain on a national sample of 11,804 ten-year olds. The first section describes an attempt to pick out cases of “specific developmental dyslexia” (Critchley 1970), a constellation or syndrome of difficulties which some believe to be recognizable clinically. When specified criteria for dyslexia were used, 269 children qualified as dyslexic (2.28 percent of the sample). These included 223 boys and 46 girls, for a ratio of 4.51 to 1. Two possible difficulties in interpreting these data are discussed, and a defense is offered of the criteria used.
Since some recent research papers report a gender ratio much nearer 1:1 (Shaywitz et al. 1990; Wadsworth et al. 1992; Lubs et al. 1993), those papers were examined for possible differences in procedure; it was found that the definition of dyslexia they used was “poor reading in relation to intelligence.” We carried out a further analysis on our own data using the same criterion. Of the 494 children who qualified as dyslexic on the basis of discrepancy criteria alone (4.19 percent of the sample), 314 were boys and 180 were girls for a ratio of 1.69 to 1. It seems, therefore, that the apparent differences in gender ratio reported in the literature have arisen because different criteria for dyslexia have been used.
We argue that the definition based on clinical criteria leads to a more powerful taxonomy and that the widespread equation of “dyslexia” with “poor reading” is a hindrance to progress.
We used voxel-based morphometry (VBM) to examine human brain asymmetry and the effects of sex and handedness on brain structure in 465 normal adults. We observed significant asymmetry of cerebral grey and white matter in the occipital, frontal, and temporal lobes (petalia), including Heschl's gyrus, planum temporale (PT) and the hippocampal formation. Males demonstrated increased leftward asymmetry within Heschl's gyrus and PT compared to females. There was no significant interaction between asymmetry and handedness and no main effect of handedness. There was a significant main effect of sex on brain morphology, even after accounting for the larger global volumes of grey and white matter in males. Females had increased grey matter volume adjacent to the depths of both central sulci and the left superior temporal sulcus, in right Heschl's gyrus and PT, in right inferior frontal and frontomarginal gyri and in the cingulate gyrus. Females had significantly increased grey matter concentration extensively and relatively symmetrically in the cortical mantle, parahippocampal gyri, and in the banks of the cingulate and calcarine sulci. Males had increased grey matter volume bilaterally in the mesial temporal lobes, entorhinal and perirhinal cortex, and in the anterior lobes of the cerebellum, but no regions of increased grey matter concentration.
At its simplest, voxel-based morphometry (VBM) involves a voxel-wise comparison of the local concentration of gray matter between two groups of subjects. The procedure is relatively straightforward and involves spatially normalizing high-resolution images from all the subjects in the study into the same stereotactic space. This is followed by segmenting the gray matter from the spatially normalized images and smoothing the gray-matter segments. Voxel-wise parametric statistical tests which compare the smoothed gray-matter images from the two groups are performed. Corrections for multiple comparisons are made using the theory of Gaussian random fields. This paper describes the steps involved in VBM, with particular emphasis on segmenting gray matter from MR images with nonuniformity artifact. We provide evaluations of the assumptions that underpin the method, including the accuracy of the segmentation and the assumptions made about the statistical distribution of the data.
Gender differences in neuropsychological functioning of patients with psychiatric disorders have been studied extensively in the last years. The available studies provide conflicting results, which can be attributed to the complexity of variables influencing cognitive sex differences. In the present study, we tried to evaluate the magnitude of gender differences in verbal and visual–spatial functions and to correlate the results with a self-rating of these abilities in healthy men and women. Ninety-seven college students (51 women and 46 men) were examined with a neuropsychological battery, focusing on verbal and visual–spatial abilities. In general, we found, that women tend to perform at a higher level than men on most verbal tests and men outperfom women on visual–spatial tasks. Nevertheless, it is worth mentioning, that the effect sizes were generally small, which suggests the assumption, that the overlap in the distribution of male and female scores is much greater than the difference between them. Additionally, in a self-rating scale, men rated their spatial abilities significantly superior to those of women, while women did not rate their verbal abilities superior to those of men. In this context, the relevance of socio-cultural factors, educational factors and training on the occurrence of sex differences is highlighted, as these factors add significantly to the overall explanation of neuropsychological task-performance.
Sex and ethnic differences in the frequency of Parkinson's disease have become increasingly important, because putative genetic and environmental risk factors have been identified. The authors estimated the prevalence and incidence of Parkinson's disease in a culturally diverse community in New York City over a 4-year period (January 1, 1988–December 31, 1991) using a disease registry substantiated, for older individuals, by a subsequent survey of a random sample of Medicare recipients between January 1, 1992, and December 31, 1993. The prevalence rate was 107 per 100,000 persons, and over a 3-year period the average incidence rate was 13 per 100,000 person-years. Age-adjusted prevalence rates were lower for women than for men in each ethnic group and were lower for blacks than for whites and Hispanics. Incidence rates were highest among black men, but they were otherwise comparable across the sex and ethnic groups. The estimated cumulative incidence of Parkinson's disease up to age 90 years was lower for women than for men, which could partially explain the lower prevalence rate. By ethnic group, the cumulative incidence was higher for blacks than for whites and Hispanics, but more deaths occurred among incident black cases. Discrepant prevalence and incidence rates of Parkinson's disease among blacks and women warrant further investigation. While selective mortality could partially account for this paradox, it is also possible that a delay in diagnosis due to limited access to appropriate health services among these individuals could have resulted in the observed discordant rates of disease.
It is often difficult to make the clinical distinction between acute mitral regurgitation caused by papillary muscle dysfunction or rupture and ventricular septal defect complicating an acute myocardial infarction. A case of a patient with rapidly progressive congestive heart failure and a loud murmur is presented. Echocardiography strongly suggested the presence of a flail posterior mitral leaflet. However, the patient was subsequently found to have rupture of the interventricular septum. This diagnosis was made with bedside right heart catheterization and was later confirmed by left ventriculography and direct inspection at the time of surgery. The mitral valve apparatus was completely normal. Thus this case demonstrates the apparent lack of specificity of the accepted echocardiographic criteria for flail mitral leaflet and acutely ruptured interventricular septum, and the potential necessity of cardiac catheterization to distinguish between these entities.
A series of four dual task experiments was conducted in which different groups of right-handed Ss (N1 = 24; N2 = N3 = N4 = 18) simultaneously performed a repetitive finger tapping task in conjunction with: (a) a verbal fluency task (Experiment I); (b) listening to logical memory stories from the Weschler Memory Scale (Experiment II); (c) reading logical memory stories (Experiment III); and (d) scanning an array of faces (Experiment IV). Results indicated that all three verbal tasks produced significant asymmetrical depression in tapping performance, with the right hand being more disrupted then the left. The visuo-spatial task, however, exerted symmetrical bilateral depression of both hands. Performance on the cognitive tasks (number of words produced in the verbal fluency task; recall of stories either listened to or read, recognition of faces) was unaffected by simultaneous digital tapping.
Ninety-four epileptic patients who had undergone the carotid amytal test were evaluated in order to determine whether sex affects the pattern of hemispheric reorganization following cerebral injury. Our data suggest that the period during which hemispheric reorganization for speech can occur differs between the sexes. Females have a relatively short window, with reorganization most likely during the first year of life. The length of this window is more difficult to define for males but may extend until puberty. The period during which a shift to left-handedness can occur does not appear to be affected by gender. Here, both males and females seem to show a relatively short window.
In a retrospective survey, 487 research projects approved by the Central Oxford Research Ethics Committee between 1984 and 1987, were studied for evidence of publication bias. As of May, 1990, 285 of the studies had been analysed by the investigators, and 52% of these had been published. Studies with statistically significant results were more likely to be published than those finding no difference between the study groups (adjusted odds ratio [OR] 2.32; 95% confidence interval [Cl] 1.25-4.28). Studies with significant results were also more likely to lead to a greater number of publications and presentations and to be published in journals with a high citation impact factor. An increased likelihood of publication was also associated with a high rating by the investigator of the importance of the study results, and with increasing sample size. The tendency towards publication bias was greater with observational and laboratory-based experimental studies (OR = 3.79; 95% Cl = 1.47-9.76) than with randomised clinical trials (OR = 0.84; 95% Cl = 0.34-2.09). We have confirmed the presence of publication bias in a cohort of clinical research studies. These findings suggest that conclusions based only on a review of published data should be interpreted cautiously, especially for observational studies. Improved strategies are needed to identify the results of unpublished as well as published studies.
Nine-hundred and eighty-one right-handed and 55 left-handed subjects were required to tap with a pen for 10 secs between targets 6 cm apart whilst either saying nothing, reciting a tongue-twister or saying la-la. The numbers of dots produced in 10 secs in each condition were analysed. The right-handed group demonstrated the usually found degradation in their right-hand performance whilst reciting the meaningful words, but showed a lesser effect when saying la-la. Their left-handed performance was essentially unaffected. Absolutely no evidence for the presence of a sex difference in lateralization of language was found. The much smaller sample of left-handed subjects presented a complex picture of no significant effects, whether they were the sole left-handers in their family, or had other left-handed close relations.