Sex differences in cognition

Brain-Based Predictions of Psychiatric Illness-Linked Behaviors Across the Sexes

BACKGROUND

Individual differences in functional brain connectivity can be used to predict both the presence of psychiatric illness and variability in associated behaviors. However, despite evidence for sex differences in functional network connectivity and in the prevalence, presentation, and trajectory of psychiatric illnesses, the extent to which disorder-relevant aspects of network connectivity are shared or unique across the sexes remains to be determined.

METHODS

In this work, we used predictive modeling approaches to evaluate whether shared or unique functional connectivity correlates underlie the expression of psychiatric illness-linked behaviors in males and females in data from the Adolescent Brain Cognitive Development Study (N = 5260; 2571 females).

RESULTS

We demonstrate that functional connectivity profiles predict individual differences in externalizing behaviors in males and females but predict internalizing behaviors only in females. Furthermore, models trained to predict externalizing behaviors in males generalize to predict internalizing behaviors in females, and models trained to predict internalizing behaviors in females generalize to predict externalizing behaviors in males. Finally, the neurobiological correlates of many behaviors are largely shared within and across sexes: functional connections within and between heteromodal association networks, including default, limbic, control, and dorsal attention networks, are associated with internalizing and externalizing behaviors.

CONCLUSIONS

Taken together, these findings suggest that shared neurobiological patterns may manifest as distinct behaviors across the sexes. Based on these results, we recommend that both clinicians and researchers carefully consider how sex may influence the presentation of psychiatric illnesses, especially those along the internalizing-externalizing spectrum.

The Interference of a Baseline with Children's Orientation Judgement Need Not Entirely Mask Their Contextual Responsiveness

Children below the age of seven are very influenced by the orientation of the external frame of reference when they attempt to lay down a stimulus to match that of a tilted target. If, however, the target be set upon a baseline the children seem unable to benefit from salient parallel alignment cues. By modifying the usual design it is shown that children can remain able to take their bearings from contextual alignment even when setting a pointer upon a baseline; but the effect is only revealed in a complex three-way interaction. Contextual sensitivity is thus not abolished, but masked; and its re-emergence is in an apparently anomalous form.

Effects of Speaking Speed on Cerebral Lateralization of Speech Assessed by a Dual-Task Interference Paradigm

Cerebral asymmetry for speech was assessed by means of a verbal-manual interference paradigm in a sample of 16 right-handed men at two different speaking rates. Normal speech rate disrupted the right hand significantly more than the left, whereas increased speech rate showed no differences between right and left hands during verbal-manual interference tasks. This result suggests a role of speaking speed in modifying cerebral motor functions related to speech production.

Umbilical cord androgens and estrogens in relation to verbal and nonverbal abilities at age 10 in the general population

Sex differences in verbal and nonverbal abilities are a contentious area of research. Prenatal steroids have been shown to have masculinizing effects on the brain that may affect the development of nonverbal and verbal abilities in later life. The current study examined a wide range of biologically active sex steroids (both androgens and estrogens) in umbilical cord blood at birth in a large pregnancy cohort in relation to performance on nonverbal (Raven's Coloured Progressive Matrices) and verbal (Clinical Evaluation of Language Fundamentals-3 and the Peabody Picture Vocabulary Test-III) measures at age 10 years. Overall, Androgen and Estrogen composites in cord blood were not found to be predictive of performance on verbal and nonverbal measures at age 10. These data suggest that late gestation sex steroids do not exert a major effect on nonverbal and verbal abilities in middle childhood.

Sex Differences in Wechsler Subtest Profiles as Seen through the Personality Assessment System

Using sufficiently large samples, statistically significant sex differences are demonstrated for all 10 of the Wechsler subtest dimensions employed by the Personality Assessment System. The magnitudes of these effects vary widely. 85% to 90% of the effects are associated with the basic level of the Personality Assessment System and, to this degree, it is suggested that sex differences on the WAIS are learned rather than innate. Inferences based on these effects are justifiable in some but not all individual cases.

Sexing the Phallocentric Pages of Psychology: Repopulation is Not Enough

Whilst the case for the repopulation of psychology made by Billig is supported in principle, it is argued that repopulation without serious reassessment of the underlying phallocentric bias in psychology is not enough. It may even act to reinforce reactionary tendencies within the discipline through coating them in a veneer of liberalism. Following critiques of the inherent sexism in both science and psychology, feminists have already moved to repopulate the discipline, taking a more radical step than is suggested by Billig's `Median Case Reconstruction'. Critiques of objectivity and neutrality, increased reflexivity, and acknowledgements of subjectivity are commonplace in feminist psychology. Yet as feminist critiques and genuine repopulation threaten the very foundations of psychology, it is not surprising that they are not readily accepted by the academic gatekeepers. It is concluded that only a paradigm shift will allow Billig's arguments to be taken seriously in mainstream psychology, and a feminist analysis suggests that this is a long way off.

Sex Differences in Spatial Ability: A Critique

This paper examines the controversy surrounding the two main problem areas of this field. The first problem is the definition and description of spatial ability, there being concern over precisely what is measured by different tests, and the lack of independence of such tests. The second area deals with the aetiology of sex differences in spatial ability. The most compelling current theory, that of a recessive gene influence, has certain anomalies which require additional factors, such as sex-typing or hormonal limitation, to be brought in to complete the explanation, although these too require further clarification. Searching for a cause of sex differences without an understanding of the cognitive strategies involved would seem to be a sterile pursuit, and it is proposed that an analysis of spatial problem solving (e.g. in mental rotation) will shed more light on individual differences, set in the context of genetic and environmental influences.

Gender Related Learning Style Patterns of Middle School Pupils

Women's development has emerged as a fairly recent area of research. The learning style model has been tested extensively in the areas of teaching and learning. Yet empirical studies in the area of gender related preferences are limited and contradictory. The focus of the present study was to investigate learning style differences which may be a function of gender characteristics. Of the 211 subjects in the present study, which used the middle school as its context, 108 were males and 103 were females. Subjects were administered the Learning Style Inventory and discriminant analysis was conducted to determine if there were significant between-group differences in learning style. Six of the twenty-two variables significantly discriminated between the male and female group. Implications of the study were discussed.

Odours reduce the magnitude of object substitution masking for matching visual targets in females

Recent evidence suggests that olfactory stimuli can influence early stages of visual processing, but there has been little focus on whether such olfactory-visual interactions convey an advantage in visual object identification. Moreover, despite evidence that some aspects of olfactory perception are superior in females than males, no study to date has examined whether olfactory influences on vision are gender-dependent. We asked whether inhalation of familiar odorants can modulate participants' ability to identify briefly flashed images of matching visual objects under conditions of object substitution masking (OSM). Across two experiments, we had male and female participants (N = 36 in each group) identify masked visual images of odour-related objects (e.g., orange, rose, mint) amongst nonodour-related distracters (e.g., box, watch). In each trial, participants inhaled a single odour that either matched or mismatched the masked, odour-related target. Target detection performance was analysed using a signal detection (d') approach. In females, but not males, matching odours significantly reduced OSM relative to mismatching odours, suggesting that familiar odours can enhance the salience of briefly presented visual objects. We conclude that olfactory cues exert a subtle influence on visual processes by transiently enhancing the salience of matching object representations. The results add to a growing body of literature that points towards consistent gender differences in olfactory perception.

The genetic relationship between handedness and neurodevelopmental disorders

Handedness and brain asymmetry have been linked to neurodevelopmental disorders such as dyslexia and schizophrenia. The genetic nature of this correlation is not understood. Recent discoveries have shown handedness is determined in part by the biological pathways that establish left/right (LR) body asymmetry during development. Cilia play a key role in this process, and candidate genes for dyslexia have also been recently shown to be involved in cilia formation. Defective cilia result not only in LR body asymmetry phenotypes but also brain midline phenotypes such as an absent corpus callosum. These findings suggest that the mechanisms for establishing LR asymmetry in the body are reused for brain midline development, which in turn influences traits such as handedness and reading ability.

Sex differences in mathematical reasoning ability in intellectually talented preadolescents: Their nature, effects, and possible causes

Several hundred thousand intellectually talented 12-to 13-year-olds have been tested nationwide over the past 16 years with the mathematics and verbal sections of the Scholastic Aptitude Test (SAT). Although no sex differences in verbal ability have been found, there have been consistent sex differences favoring males in mathematical reasoning ability, as measured by the mathematics section of the SAT (SAT-M). These differences are most pronounced at the highest levels of mathematical reasoning, they are stable over time, and they are observed in other countries as well. The sex difference in mathematical reasoning ability can predict subsequent sex differences in achievement in mathematics and science and is therefore of practical importance. To date a primarily environmental explanation for the difference in ability has not received support from the numerous studies conducted over many years by the staff of Study of Mathematically Precocious Youth (SMPY) and others. We have studied some of the classical environmental hypotheses: attitudes toward mathematics, perceived usefulness of mathematics, confidence, expectations/ encouragement from parents and others, sex-typing, and differential course-taking. In addition, several physiological correlates of extremely high mathematical reasoning ability have been identified (left-handedness, allergies, myopia, and perhaps bilateral representation of cognitive functions and prenatal hormonal exposure). It is therefore proposed that the sex difference in SAT-M scores among intellectually talented students, which may be related to greater male variability, results from both environmental and biological factors.