-
[show abstract]
[hide abstract]
ABSTRACT: Executive control development typically has been conceptualized to result from quantitative changes in the efficiency of the underlying processes. In contrast, the present study addressed the possibility of qualitative change with age by examining how children and adults detect task switches. Participants in three age groups (5- and 10-year-old children, young adults) completed two conditions of a cued task-switching paradigm where task cues were presented either in isolation or in conjunction with transition cues. Five-year-olds performed better with transition cues, whereas the reverse effect was observed at age 10 and with adults. Unlike 5-year-olds who detect switches after semantically processing cues, older participants strategically detect switches based on perceptual processing only. Age-related qualitative changes promote increasingly optimal adjustment of executive resources with age.
Cognition 04/2013; 128(1):1-12. · 3.16 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Despite acknowledgement of the importance of executive control for learning and behavior, there is a dearth of research charting its developmental trajectory as it unfolds against the background of children's sociofamilial milieus. Using a prospective, cohort-sequential design, this study describes growth trajectories for inhibitory control and cognitive flexibility across the preschool period in relation to child sex and sociofamilial resources. At ages 3, 3.75, 4.5, and 5.25 years, children (N = 388) from a broad range of social backgrounds were assessed using the Shape School, a graduated measure of executive control incorporating baseline, inhibitory control, and cognitive flexibility conditions. Measures of children's proximal access to learning resources and social network supports were collected at study entry. Findings revealed substantial gains in accuracy and speed for all Shape School conditions, these gains being particularly accelerated between ages 3 and 3.75 years. Improvements in inhibitory control were more rapid than those in flexible switching. Age-related differences in error and self-correction patterns on the Shape School also suggest qualitative changes in the underlying processes supporting executive performance across early childhood. Children from homes with fewer learning resources showed a subtle lag in inhibition and cognitive flexibility performance that persisted at kindergarten entry age, despite exhibiting gradual catch up to their more advantaged peers for the nonexecutive, baseline task condition. The study provides a unique characterization of the early developmental pathways for inhibitory control and cognitive flexibility and highlights the critical role of stimulating early educational resources for shaping the dynamic ontogeny of executive control. (PsycINFO Database Record (c) 2012 APA, all rights reserved).
Developmental Psychology 10/2012; · 3.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The development of response inhibition was investigated using a computerized go/no-go task, in a lagged sequential design where 376 preschool children were assessed repeatedly between 3.0 and 5.25 years of age. Growth curve modeling was used to examine change in performance and predictors of individual differences. The most pronounced change was observed between 3 and 3.75 years. Better working memory and general cognitive ability were related to more accurate performance at all ages, but relations with speed changed with age, where better cognitive skills were initially related to slower responding, but faster responding at later ages. Boys responded more quickly and were more accurate on go trials, whereas girls were better able to withhold responding on no-go trials.
Child Development 04/2012; 83(4):1245-61. · 4.72 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Impairments in executive functions (EF) are consistently associated with attention deficit hyperactivity disorder (ADHD) and to a lesser extent, with disruptive behavior disorder (DBD), that is, oppositional defiant disorder or conduct disorder, in school-aged children. Recently, larger numbers of children with these disorders are diagnosed earlier in development, yet knowledge about impairments in clinically diagnosed preschool children and the role of comorbidity is limited. Therefore, the aim of the current study was to examine EF in clinically referred preschool children with a clinical diagnosis of ADHD, DBD and ADHD + DBD.
Participants were 202 children aged 3.5-5.5 years, 61 with ADHD only, 33 with DBD only, 52 with comorbid ADHD + DBD and 56 typically developing children. Five EF tasks were administered.
Confirmatory factor analysis showed that the two-factor model (inhibition and working memory) fit the data better than a one-factor model in this clinical sample. Preschoolers with ADHD displayed inhibition deficits, also after controlling for IQ. Likewise, preschoolers with DBD displayed impaired inhibition, but when IQ was controlled differences were carried mostly by the effect on the task where motivational demands were high (i.e. when tangible rewards were used). This pattern was also found in the interaction between ADHD and DBD; impaired inhibition in the comorbid group, however, was more severe than in the DBD group. Regarding working memory, few group differences were found.
Clinically diagnosed preschool children with ADHD showed robust inhibition deficits, whereas preschool children with DBD showed impaired inhibition especially where motivational incentives were prominent. Severity of inhibition impairment in the comorbid group was similar to the ADHD group.
Journal of Child Psychology and Psychiatry 02/2012; 53(2):111-9. · 4.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study addressed the respective contributions of inhibition and working memory to two underlying components of flexibility, goal representation (as assessed by mixing costs) and switch implementation (as assessed by local costs), across the preschool period. By later preschool age (4 years, 6 months and 5 years, 3 months), both inhibition and working-memory performance were associated with mixing costs, but not with local costs, whereas no relation was observed earlier (3 years, 9 months). The relations of inhibition and working memory to flexibility appear to emerge late in the preschool period and are mainly driven by goal representation.
Developmental Neuropsychology 02/2012; 37(2):99-118. · 2.56 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The effects of tobacco exposure are typically examined by comparing groups based on a cut-score of self-reported number of cigarettes or bioassays collected in cross-sectional studies. This study introduces a new fuzzy clustering method that facilitates detection of subtle exposure effects by objectively deriving subgroups from modeling multidimensional exposure measures. We test the new method on a known exposure effect (fetal growth) and report on the graded exposure effect detected in a pregnancy cohort.
A total of 978 pregnant women were enrolled from 1986 to 1992 in the Maternal Infant Smoking Study of East Boston (MISSEB). Four kinds of exposure data were used to generate exposure groups: self-reported smoking, cotinine levels, nicotine levels, and nicotine dependence scores. Subgroups were identified via a comprehensive validation procedure. The results from MISSEB (number of exposure clusters, exposure effects on birth weight, body length, and head circumference) were compared with those obtained in a separate cohort.
Using our new method in MISSEB, the same number of clusters was generated as previously, and graded exposure effects were again detected. Neonates with heavier exposure weighed less at birth relative to nonexposed neonates, with no difference between lighter-exposed and nonexposed neonates.
The same graded prenatal exposure effect emerges for known exposure-related outcomes across 2 different studies, about 2 decades apart. Our new method characterizes the degree of prenatal exposure, with the potential to help detect subtler effects on developmental outcomes, such as deficits in growth or development, neonatal temperament and behavior, and psychological functioning.
Nicotine & Tobacco Research 01/2012; 14(9):1115-20. · 2.58 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To examine the prevalence of behavior disorders in a 2001-2003 birth cohort of extremely preterm/extremely low birth weight (EPT/ELBW, <28 weeks gestational age or <1000 g) children in kindergarten.
We compared 148 EPT/ELBW children with 111 term-born normal birth weight classmate controls on reports of psychiatric symptoms obtained from parent interview (Children's Interview for Psychiatric Syndromes-Parent Form [P-ChIPS]), parent and teacher ratings of behavior (Child Behavior Checklist, Teacher's Report Form, and Behavior Rating Inventory of Executive Function), and teacher ratings of social functioning (School Social Behavior Scales, second edition). Associations of behavior disorders with global cognitive ability and tests of executive function were also examined within the EPT/ELBW group.
Rates of attention-deficit/hyperactivity disorder combined on psychiatric interview were about twice as high for the EPT/ELBW group than for the normal birth weight group, odds ratio (95% confidence interval) = 2.50 (1.34, 4.68), p = .004. The EPT/ELBW group also had much higher rates of teacher-identified disorders in attention, behavior self-regulation, and social functioning, with odds ratios (95% confidence intervals) ranging from 3.35 (1.64, 6.83) to 18.03 (4.12, 78.94), all p values <.01. Attention-deficit/hyperactivity disorder and impaired behavior self-regulation were associated with deficits on tests of executive function but not with global cognitive impairment.
The findings document increased rates of disorders in attention, behavior self-regulation, and socialization in EPT/ELBW children and suggest that deficits on tests of executive function are associated with some of these disorders. Early identification and intervention for these disorders are needed to promote early adjustment to school and facilitate learning progress.
Journal of developmental and behavioral pediatrics: JDBP 01/2012; 33(3):202-13. · 2.27 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Our objectives were to examine cognitive outcomes for extremely preterm/extremely low birth weight (EPT/ELBW, gestational age <28 weeks and/or birth weight <1000 g) children in kindergarten and the associations of these outcomes with neonatal factors, early childhood neurodevelopmental impairment, and socioeconomic status (SES). The sample comprised a hospital-based 2001-2003 birth cohort of 148 EPT/ELBW children (mean birth weight 818 g; mean gestational age 26 weeks) and a comparison group of 111 term-born normal birth weight (NBW) classmate controls. Controlling for background factors, the EPT/ELBW group had pervasive deficits relative to the NBW group on a comprehensive test battery, with rates of cognitive deficits that were 3 to 6 times higher in the EPT/ELBW group. Deficits on a measure of response inhibition were found in 48% versus 10%, odds ratio (95% confidence interval) = 7.32 (3.32, 16.16), p < .001. Deficits on measures of executive function and motor and perceptual-motor abilities were found even when controlling for acquired verbal knowledge. Neonatal risk factors, early neurodevelopmental impairment, and lower SES were associated with higher rates of deficits within the EPT/ELBW group. The findings document both global and selective cognitive deficits in EPT/ELBW children at school entry and justify efforts at early identification and intervention.
Journal of the International Neuropsychological Society 09/2011; 17(6):1067-79. · 2.76 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Latent variable modeling methods have demonstrated utility for understanding the structure of executive control (EC) across development. These methods are utilized to better characterize the relation between EC and mathematics achievement in the preschool period, and to understand contributing sources of individual variation. Using the sample and battery of laboratory tasks described in Wiebe, Espy and Charak (2008), latent EC was related strongly to emergent mathematics achievement in preschool, and was robust after controlling for crystallized intellectual skills. The relation between crystallized skills and emergent mathematics differed between girls and boys, although the predictive association between EC and mathematics did not. Two dimensions of the child 's social environment contributed to mathematics achievement: social network support through its relation to EC and environmental stressors through its relation with crystallized skills. These findings underscore the need to examine the dimensions, mechanisms, and individual pathways that influence the development of early competence in basic cognitive processes that underpin early academic achievement.
Developmental Science 07/2011; 14(4):679-92. · 3.89 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The current study addressed the role of switch detection in cognitive flexibility by testing the effect of transition cues (i.e., cues that directly signal the need to switch or maintain a given task goal) in a cued set-shifting paradigm at 5 years of age. Children performed better, especially on switch trials, when transition cues were combined with traditional task cues (i.e., cues that directly signal the relevant task on a given trial) relative to conditions without transition cues. This effect was not influenced by explicit knowledge of transition cues or transition cue transparency, suggesting that transition cues did not need to be semantically processed to be beneficial. These findings reveal that young children's difficulties in set-shifting situations stem partially from failures to monitor for the need to switch.
Journal of Experimental Child Psychology 02/2011; 109(3):353-70. · 3.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Despite the widespread recognition of the importance of executive control (EC) in externalizing psychopathology, the relation between EC and problem behavior has not been well characterized, particularly in typically developing preschoolers.
Using the sample, battery of laboratory tasks, and latent variable modeling methods described in Wiebe, Espy, and Charak (2008), systematic latent dimensions of parent-rated problem behavior, measured by integrating scales from developmental and clinical traditions, were determined empirically, and then were related to EC.
Substantial relations between EC and problem behaviors were revealed by extracting the common variance of interest and eliminating extraneous variance, which were robust to estimated child intelligence and differed somewhat in preschool boys and girls.
Preschool EC measured by laboratory tasks appears to tap abilities that strongly and robustly support broad control processes enabling behavioral regulation across cognitive and emotional domains.
Journal of Child Psychology and Psychiatry 01/2011; 52(1):33-46. · 4.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Smoking during pregnancy is a persistent public health problem that has been linked to later adverse outcomes. The neonatal period--the first month of life--carries substantial developmental change in regulatory skills and is the period when tobacco metabolites are cleared physiologically. Studies to date mostly have used cross-sectional designs that limit characterizing potential impacts of prenatal tobacco exposure on the development of key self-regulatory processes and cannot disentangle short-term withdrawal effects from residual exposure-related impacts. In this study, pregnant participants (N = 304) were recruited prospectively during pregnancy, and smoking was measured at multiple time points, with both self-report and biochemical measures. Neonatal attention, irritable reactivity, and stress dysregulation were examined longitudinally at three time points during the first month of life, and physical growth indices were measured at birth. Tobacco-exposed infants showed significantly poorer attention skills after birth, and the magnitude of the difference between exposed and nonexposed groups attenuated across the neonatal period. In contrast, exposure-related differences in irritable reactivity largely were not evident across the 1st month of life, differing marginally at 4 weeks of age only. Third-trimester smoking was associated with pervasive, deleterious, dose–response impacts on physical growth measured at birth, whereas nearly all smoking indicators throughout pregnancy predicted level and growth rates of early attention. The observed neonatal pattern is consistent with the neurobiology of tobacco on the developing nervous system and fits with developmental vulnerabilities observed later in life.
Developmental Psychology 11/2010; 47(1):153-6. · 3.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Despite efforts to control for confounding variables using stringent sampling plans, selection bias typically exists in observational studies, resulting in unbalanced comparison groups. Ignoring selection bias can result in unreliable or misleading estimates of the causal effect.
Generalized boosted models were used to estimate propensity scores from 42 confounding variables for a sample of 361 neonates. Using emergent neonatal attention and orientation skills as an example developmental outcome, we examined the impact of tobacco exposure with and without accounting for selection bias. Weight at birth, an outcome related to tobacco exposure, also was used to examine the functionality of the propensity score approach.
Without inclusion of propensity scores, tobacco-exposed neonates did not differ from their nonexposed peers in attention skills over the first month or in weight at birth. When the propensity score was included as a covariate, exposed infants had marginally lower attention and a slower linear change rate at 4 weeks, with greater quadratic deceleration over the first month. Similarly, exposure-related differences in birth weight emerged when propensity scores were included as a covariate.
The propensity score method captured the selection bias intrinsic to this observational study of prenatal tobacco exposure. Selection bias obscured the deleterious impact of tobacco exposure on the development of neonatal attention. The illustrated analytic strategy offers an example to better characterize the impact of prenatal tobacco exposure on important developmental outcomes by directly modeling and statistically accounting for the selection bias from the sampling process.
Nicotine & Tobacco Research 10/2010; 12(12):1211-9. · 2.58 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although the structure of executive function (EF) during adulthood is characterized by both unity and diversity, recent evidence suggests that preschool EF may be best described by a single factor. The latent structure of EF was examined in 228 3-year-olds using confirmatory factor analysis. Children completed a battery of executive tasks that differed in format and response requirements and in putative working memory and inhibitory control demands. Tasks appeared to be age appropriate, with adequate sensitivity across the range of performance and without floor or ceiling effects. Tests of the relative fit of several alternative models supported a single latent EF construct. Measurement invariance testing revealed less proficient EF in children at higher sociodemographic risk relative to those at lower risk and no differences between boys and girls. At 3years of age, when EF skills are emerging, EF appears to be a unitary, more domain-general process.
Journal of Experimental Child Psychology 09/2010; 108(3):436-52. · 3.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper proposes a new nonlinear classifier based on a generalized Choquet integral with signed fuzzy measures to enhance the classification accuracy and power by capturing all possible interactions among two or more attributes. This generalized approach was developed to address unsolved Choquet-integral classification issues such as allowing for flexible location of projection lines in n-dimensional space, automatic search for the least misclassification rate based on Choquet distance, and penalty on misclassified points. A special genetic algorithm is designed to implement this classification optimization with fast convergence. Both the numerical experiment and empirical case studies show that this generalized approach improves and extends the functionality of this Choquet nonlinear classification in more real-world multi-class multi-dimensional situations.
Pattern Recognition 01/2010; 43(4):1393-1401. · 2.29 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Methods for identifying meaningful growth patterns of longitudinal trial data with both nonignorable intermittent and drop-out missingness are rare. In this study, a combined approach with statistical and data mining techniques is utilized to address the nonignorable missing data issue in growth pattern recognition. First, a parallel mixture model is proposed to model the nonignorable missing information from a real-world patient-oriented study and concurrently to estimate the growth trajectories of participants. Then, based on individual growth parameter estimates and their auxiliary feature attributes, a fuzzy clustering method is incorporated to identify the growth patterns. This case study demonstrates that the combined multi-step approach can achieve both statistical gener ality and computational efficiency for growth pattern recognition in longitudinal studies with nonignorable missing data.
International Journal of Information Technology and Decision Making 09/2009; 8(3):491-513. · 1.31 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The extremes of birth weight and preterm birth are known to result in a host of adverse outcomes, yet studies to date largely have used cross-sectional designs and variable-centered methods to understand long-term sequelae. Growth mixture modeling (GMM) that utilizes an integrated person- and variable-centered approach was applied to identify latent classes of achievement from a cohort of school-age children born at varying birth weights. GMM analyses revealed 2 latent achievement classes for calculation, problem-solving, and decoding abilities. The classes differed substantively and persistently in proficiency and in growth trajectories. Birth weight was a robust predictor of class membership for the 2 mathematics achievement outcomes and a marginal predictor of class membership for decoding. Neither visuospatial-motor skills nor environmental risk at study entry added to class prediction for any of the achievement skills. Among children born preterm, neonatal medical variables predicted class membership uniquely beyond birth weight. More generally, GMM is useful in revealing coherence in the developmental patterns of academic achievement in children of varying weight at birth and is well suited to investigations of sources of heterogeneity.
Neuropsychology 08/2009; 23(4):460-74. · 3.82 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Because the power properties of traditional repeated measures and hierarchical multivariate linear models have not been clearly determined in the balanced design for longitudinal studies in the literature, the authors present a power comparison study of traditional repeated measures and hierarchical multivariate linear models under 3 variance-covariance structures. The results from a full-crossed simulation design suggest that traditional repeated measures have significantly higher power than do hierarchical multivariate linear models for main effects, but they have significantly lower power for interaction effects in most situations. Significant power differences are also exhibited when power is compared across different covariance structures.
The Journal of Experimental Education 04/2009; 77(3):215-254. · 1.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Children with very low birth weight (VLBW, <1500 g) or very preterm birth (VPTB, <32 weeks gestational age or GA) have more mathematics disabilities or deficiencies (MD) and higher rates of mathematics learning disabilities (MLD) than normal birth weight term-born children (NBW, >2500 g and >36 weeks GA). MD are found even in children without global disorders in cognition or neurosensory status and when IQ is controlled, and they are associated with other learning problems and weaknesses in perceptual motor abilities and executive function. Factors related to poorer mathematics outcomes include lower birth weight and GA, neonatal complications, and possible abnormalities in brain structure. While little is known about the nature of MD in these children, studies of MLD in other neurodevelopmental disorders and in children with learning disabilities provide useful models for further investigation. Further investigation of the neuropsychological and neuropathological correlates of distinct types of mathematics difficulties is also needed. Studies along these lines will yield information about the unique features of MD in children with VLBW/VPTB and about the nature and origins of poor mathematics achievement more generally.
Developmental Disabilities Research Reviews 02/2009; 15(1):52-9. · 4.04 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Genetic factors dynamically interact with both pre- and postnatal environmental influences to shape development. Considerable attention has been devoted to gene-environment interactions (G x E) on important outcomes (A. Caspi & T. E. Moffitt, 2006). It is also important to consider the possibility that these G x E effects may vary across development, particularly for constructs like self-regulation that emerge slowly, depend on brain regions that change qualitatively in different developmental periods, and thus may be manifested differently. To illustrate one approach to exploring such developmental patterns, the relation between variation in the TaqIA polymorphism, related to D2 dopamine receptor expression and availability, and prenatal exposure to tobacco was examined in two exploratory studies. First, in 4-week-old neonates, genotype-exposure interactions were observed for attention and irritable reactivity, but not for stress dysregulation. Second, in preschool children, genotype was related to Preschool Trail Making Test (K. A. Espy and M. F. Cwik, 2004) task performance on conditions requiring executive control; children with both the A1+ genotype and a history of prenatal tobacco exposure displayed disproportionately poor performance. Despite study limitations, these results illustrate the importance of examining the interplay between genetic and prenatal environmental factors across development.
Developmental Psychology 01/2009; 45(1):31-44. · 3.21 Impact Factor
