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Geoff Sanders
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ABSTRACT: Coincidence-anticipation timing (CAT) is the ability to judge when a moving stimulus will arrive at a target. 43 articles were reviewed which investigated sex differences in this skill. Performance was typically recorded as one or more of three error measures, absolute error (AE), constant error (CE), and variable error (VE). Despite many null findings, it is argued that the evidence for a male advantage is strong, particularly for AE and VE. 10 parameters typically associated with CAT studies were analyzed (e.g., knowledge of results, number of trials, stimulus duration, and stimulus speed), but none differentiated clearly between the presence and absence of the sex difference. However, when the mean AE score was used as a measure of task difficulty, a male advantage was reliably associated with lower values of AE (easier tasks) and null findings with higher values (more difficult tasks). An attempt to compare sex difference findings from Bassin timer and real-world tasks was thwarted by the lack of studies using real-world tasks. Given little evidence for the influence of socialization on sex differences in CAT, it is suggested that the difference may have originated from the evolutionary selection of women for gathering and men for hunting.
Perceptual and Motor Skills 02/2011; 112(1):61-90. · 0.49 Impact Factor
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ABSTRACT: We report two Internet studies that investigated sex differences in the accuracy and precision of judging time to arrival. We used accuracy to mean the ability to match the actual time to arrival and precision to mean the consistency with which each participant made their judgments. Our task was presented as a computer game in which a toy UFO moved obliquely towards the participant through a virtual three-dimensional space on route to a docking station. The UFO disappeared before docking and participants pressed their space bar at the precise moment they thought the UFO would have docked. Study 1 showed it was possible to conduct quantitative studies of spatiotemporal judgments in virtual reality via the Internet and confirmed reports that men are more accurate because women underestimate, but found no difference in precision measured as intra-participant variation. Study 2 repeated Study 1 with five additional presentations of one condition to provide a better measure of precision. Again, men were more accurate than women but there were no sex differences in precision. However, within the coincidence-anticipation timing (CAT) literature, of those studies that report sex differences, a majority found that males are both more accurate and more precise than females. Noting that many CAT studies report no sex differences, we discuss appropriate interpretations of such null findings. While acknowledging that CAT performance may be influenced by experience we suggest that the sex difference may have originated among our ancestors with the evolutionary selection of men for hunting and women for gathering.
Archives of Sexual Behavior 12/2010; 40(6):1189-98. · 3.53 Impact Factor
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ABSTRACT: On average men score higher on time-constrained tests of spatial ability than women. Both brain and behaviour are influenced by prenatal and adult exposure to gonadal steroid hormones. In humans the ratio of the 2nd to 4th finger length (2D:4D) is a sexually dimorphic character that is lower in men than women and negatively correlated with testosterone levels. We report three independent studies from Sweden/London, Hungary and Liverpool confirming that 2D:4D is generally larger in women than men, that men obtain higher MRT scores than women, and demonstrating that 2D:4D is negatively correlated with MRT score in men but not women. We argue that this negative correlation between 2D:4D and spatial ability reflects the association between 2D:4D and prenatal, rather than adult, exposure to testosterone and conclude that testosterone exposure influences brain development leading to better performance on male-favouring spatial tasks.
Cortex 01/2006; 41(6):789-95. · 6.08 Impact Factor
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ABSTRACT: On average men score higher on time-constrained tests of spatial ability than women. Both brain and behaviour are influenced by prenatal and adult exposure to gonadal steroid hormones. In humans the ratio of the 2ndto 4thfinger length (2D:4D) is a sexually dimorphic character that is lower in men than women and negatively correlated with testosterone levels. We report three independent studies from Sweden/London, Hungary and Liverpool confirming that 2D:4D is generally larger in women than men, that men obtain higher MRT scores than women, and demonstrating that 2D:4D is negatively correlated with MRT score in men but not women. We argue that this negative correlation between 2D:4D and spatial ability reflects the association between 2D:4D and prenatal, rather than adult, exposure to testosterone and conclude that testosterone exposure influences brain development leading to better performance on male-favouring spatial tasks.
Cortex 01/2005; 41(6):789-795. · 6.08 Impact Factor
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ABSTRACT: The cause of transsexualism remains unclear. The hypothesis that atypical prenatal hormone exposure could be a factor in the development of transsexualism was examined by establishing whether an atypical pattern of cognitive functioning was present in homosexual transsexuals. Possible activating effects of sex hormones as a result of cross-sex hormone treatment were also studied. Female-to-male and male-to-female transsexuals were compared with female and male controls with respect to spatial ability before and after treatment. The data were consistent with an organizing effect, but there was no evidence of an activating effect. Homosexual transsexuals, who prior to hormone treatment scored in the direction of the opposite sex, may have reached a ceiling in performance and therefore do not benefit from activating hormonal effects.
Behavioral Neuroscience 01/2003; 116(6):982-8. · 2.62 Impact Factor
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ABSTRACT: We argue that within-sex variation resulting from the prenatal organizational and adult activational effects of gonadal steroid hormones has the potential to obscure between sex differences in cognitive performance and functional cerebral asymmetry. Two putative markers for prenatal testosterone, finger ridge count (FRC) asymmetry and the 2D:4D finger length ratio, have been linked to within-sex variation in cognitive performance. In particular, FRC allows the identification of men and women who show a reversal of the typical sex-related pattern of task performance. Three paradigms for the study of activational effects--seasonal, menstrual, and diurnal hormonal cycles--have evaluated changes in task performance and functional cerebral asymmetry. The performance of sex-dimorphic, but not sex-neutral, tasks changes with estrogen across the menstrual cycle and with testosterone across its seasonal and diurnal cycles. Functional cerebral asymmetry also changes systematically across both the menstrual cycle and the diurnal testosterone cycle in such a way that suggests left hemisphere performance increases as testosterone levels decline whereas right hemisphere performance increases as estrogen levels decline. In studies of sex differences, such correlates of within-sex hormone-related differences are rarely measured or controlled. Whatever the explanation for the associations of putative markers and hormone cycles with differences in cognitive abilities and cerebral asymmetry, it is clear that these relationships have the potential to contribute to the elusive nature of sex differences in cognition and functional brain organization.
Archives of Sexual Behavior 03/2002; 31(1):145-52. · 3.53 Impact Factor
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ABSTRACT: Here, in the first of two reports that test predictions from the hunter-gatherer hypothesis, we focus on sex differences in motor control. Published evidence confounds the cognitive demands, the muscles used and the spatial location in which tasks are performed. To address these issues our participants used hand or arm movements to track a moving target within near space. Study 1 identified an optimal level of task difficulty for the differentiation of male and female performance and showed that women tracked better using their hands and men using their arms. Employing the optimal level of task difficulty, Study 2 replicated the findings of Study 1 and, for men, demonstrated a significant correlation between arm tracking and performance on the nonmotor sex-dimorphic Mental Rotations task. This correlation suggests that the same or related events are responsible for the development of sex differences in motor and cognitive systems. The distal (hand) muscles are controlled by the primary motor cortex via two dorsolateral corticospinal tracts whereas the proximal (arm) muscles are controlled via two ventromedial corticospinal tracts. Our findings point to possible sex differences in these two neural pathways and they are compatible with an evolutionary origin as predicted by the hunter-gatherer hypothesis.
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ABSTRACT: Here, in the second of two linked reports, we focus on sex differences in visual processing. Study 1 presented a time estimation task in virtual space and generated the predicted Space*Sex interaction with men performing significantly better in far than in near space. Study 2 used a laboratory-based puzzle completion task in which participants saw their hands and the puzzle in far or near space. This time women performed significantly better in near than far space. Study 3 simplified the puzzle completion task. Once again the predicted Space*Sex interaction was significant but with both sexes showing significantly different performances: women better in near, men in far space. These findings are compatible with an evolutionary origin as predicted by the hunter-gatherer hypothesis. Far and near space are processed in the ventral and dorsal streams, two cortical regions more widely known as the "what" and "where" visual systems. To those traditional descriptions we suggest adding that the two streams are sex-dimorphic, with the ventral "there" system interacting with far space and favored in men and the dorsal "here" system interacting with near space and favored in women. Future studies of visual systems should consider the impact of sex differences and the spatial location of stimulus presentations.
