Have sex differences in spatial ability evolved from male competition for mating and female concern for survival?

Drawing on the theoretical and empirical foundations of two evolutionary models, we argue that, among humans and other mammals, a twofold selection process would parsimoniously account for sex-linked advantages in spatial contexts. In males, a superiority for both solving navigation-related spatial problems and understanding physical principles that apply to the behavior of projectiles could have been inherited from mating-oriented male competition involving extensive ranging and agonistic displays. In females, a form of superior spatial memory may have been shaped in relation to a costly reproduction system compelling them to safeguard their survival and that of their offspring by fostering low-risk strategies consisting of restricted navigation as well as concentration on nearby spatial cues. Based on the combined action of competition and survival pressures, we submit new predictions as to spatial sex differences in several species including humans.     

Sex differences in spatial ability: a lateralization of function approach

The current study was designed to examine whether the extent of the male advantage in performance on a spatial task was determined by the extent to which the task was right-hemisphere dependent. Participants included 108 right-handed men and women who completed the mental rotation, waterlevel, and paperfolding tasks, all of which were presented bilaterally. The results partially supported the hypothesis. On the mental rotation task, men showed a right-hemisphere advantage, whereas women showed no hemispheric differences; however, no overall sex differences were observed. On the waterlevel task, men outperformed women, and both men and women showed a right-hemisphere advantage. On the paperfolding task, no sex or hemispheric differences were observed. Although the findings of the current study were mixed, the study provides a framework for examining sex differences across different types of spatial ability.     

Sex differences in response to a panicogenic challenge procedure: an experimental evaluation of panic vulnerability in a non-clinical sample

Epidemiological studies show that women are twice as likely as men to develop panic disorder (PD) during their lifetimes. Data from retrospective studies also suggest that women are more distressed by panic and other negative emotional states than men, and that this tendency may precede the development of PD. The present prospective study sought to expand this work by evaluating sex differences in the predisposition to panic in individuals without PD or other forms of psychopathology. Participants (N=96; 52 women) were exposed to 12 panicogenic inhalations of 20% CO2-enriched air while physiological (e.g., heart rate, electrodermal response, Frontalis EMG) and self-report (e.g., subject distress, fear, frequency and severity of DSM-IV panic symptoms) response domains were monitored. As expected, magnitude of autonomic responding failed to reliably discriminate between women and men. Yet, women reported more fear and panic immediately following the challenge procedure relative to men, and this sex difference persisted when assessed again 30 min post-challenge. Implications of these results are discussed broadly in the context of biopsychosocial accounts of sex differences in the clinical presentation of PD.     

Cerebral lateralization and general intelligence: gender differences in a transcranial Doppler study

The present study evaluated cerebral lateralization during Raven's progressive matrices (RPM) paradigm in female and male subjects. Bilateral simultaneous transcranial Doppler (TCD) ultrasound was used to measure mean blood flow velocities (MBFV) in the right and left middle cerebral arteries (MCAs) in 24 (15 females and 9 males) right-handed normal subjects. The female subjects used a left hemisphere strategy, while males used a right hemisphere strategy to successfully solve RPM tasks. This implies that general intelligence is associated with neural systems within one hemisphere that are accessible to a variety of cognitive processes.     

The valence-specific laterality effect in free viewing conditions: The influence of sex, handedness, and response bias

The right hemisphere has often been viewed as having a dominant role in the processing of emotional information. Other evidence indicates that both hemispheres process emotional information but their involvement is valence specific, with the right hemisphere dealing with negative emotions and the left hemisphere preferentially processing positive emotions. This has been found under both restricted (Reuter-Lorenz & Davidson, 1981) and free viewing conditions (Jansari, Tranel, & Adophs, 2000). It remains unclear whether the valence-specific laterality effect is also sex specific or is influenced by the handedness of participants. To explore this issue we repeated Jansari et al.'s free-viewing laterality task with 78 participants. We found a valence-specific laterality effect in women but not men, with women discriminating negative emotional expressions more accurately when the face was presented on the left-hand side and discriminating positive emotions more accurately when those faces were presented on the right-hand side. These results indicate that under free viewing conditions women are more lateralised for the processing of facial emotion than are men. Handedness did not affect the lateralised processing of facial emotion. Finally, participants demonstrated a response bias on control trials, where facial emotion did not differ between the faces. Participants selected the left-hand side more frequently when they believed the expression was negative and the right-hand side more frequently when they believed the expression was positive. This response bias can cause a spurious valence-specific laterality effect which might have contributed to the conflicting findings within the literature.     

Sex role orientation and its relationship to the development of identity and moral thought

This paper examined the links among sex role orientation, ego identity development and moral reasoning. 76 female and 58 male students were assessed on Bern's sex role inventory, ego identity, care-based and justice-based moral thought. For women, identity was negatively related to femininity and positively related to androgyny. Also, high levels of care-based moral reasoning, i.e., a balanced concern for the welfare of self and others, was related to androgyny for women. There were no significant findings for men. No significant relationships were found between sex role orientation and justice-based moral reasoning. Thus, the results suggested that for women in particular, relinquishing the stereotyped sex role definition and becoming more androgynous is important for their ego identity as well as care-based moral development.     

Sex differences in historical knowledge and school grades: a 26 nation study

Sex differences among ninth grade school students in historical knowledge and grades were examined in 29 samples drawn from 26 countries. Boys obtained higher mean scores on the tests of historical knowledge in all samples, while girls obtained better grades in 22 of the samples.     

Sex differences in brain activity, personality and intelligence: a test of arousability theory

This report describes empirical tests of the theory that females have higher levels of behavioural and cerebral arousal than males and that these differences cause higher neuroticism scores in females, as well as lower female psychoticism scores and lower scores for females on the Gsar factor of intelligence. Data were obtained from 76 subjects, with equal numbers of males and females and with all adult ages represented. EEG responses to auditory stimulation were quantified in terms of the ‘amplitude, ‘rate of change of amplitude and ‘sweep variability factors obtained from a principal components analysis (PCA). Gf, Gc and Gsar intelligence scores were obtained from a PCA of sub-tests from the Wechsler Adult Intelligence Scale plus Ravens Advanced Progressive Matrices test. Personality differences were evaluated using the Neuroticism and Psychoticism scales of the Eysenck Personality Questionnaire (EPQ). Bivariate hypotheses relating sex to the arousal, intelligence and personality variables were confirmed. A PCA demonstrated that sex, neuroticism, Gsar, wakefulness and high frequency EEG activity all have high loadings on a common factor. These results are consistent with expectations generated by the cerebral arousability theory of personality and intelligence.     

Elevating the Voices of Girls in Custody for Improved Treatment and Systemic Change in the Juvenile Justice System

The U.S. juvenile justice system does not meet the needs of girls in custody, and often fails to address girls’ symptoms of trauma and high rates of sexual exploitation histories. As the system shifts away from punitive detention to a trauma‐informed approach with community‐based services, community psychologists and other helping professionals can help center the needs and experiences of girls in custody. As part of a multi‐year collaboration, our research team created a confidential youth advisory process in one juvenile detention center (JDC). We acted as liaisons between the girls in custody and JDC administrators, reporting girls’ feedback to agencies at monthly meetings. Participant confidentiality, safety, and consent were priorities. The girls’ feedback, which was conceptualized within a System Responsiveness and hierarchy of needs framework, led JDC probation and mental health staff to improve services (e.g., better laundry system, longer showers, warmer food), climate (e.g., consistent reward system, confidentiality of grievances), and treatment (e.g., increase focus on gender and culture) to reduce the trauma of incarceration among girls in custody. Girls’ feedback also catalyzed systemic change that led to a reduction in the JDC population in favor of wraparound community‐based services better suited to meet girls’ needs. Implications for community psychology values and the juvenile justice system, including the benefits and challenges of this type of collaboration, are discussed.     

What do Raven's Matrices measure? An analysis in terms of sex differences

Although it is sometimes claimed that Raven's Matrices provide an almost pure measure of g, there is evidence that the easier items in the Standard Progressive Matrices and in Set I of the Advanced Matrices measure a perceptual or Gestalt factor distinct from the more analytic items in the rest of the tests. There is also, however, both factor analytic and experimental evidence that these analytic items fall into two partially separate groups, distinguishable by the type of rule needed for their solution in the analysis proposed by Carpenter, Just, and Schell (1990) [Carpenter, P. A., Just, M. A., Schell, P. (1990). What one intelligence test measures: A theoretical account of the processing in the Raven's Progressive Matrices Test. Psychological Review, 97, 404–431]. Re-analysis of published data suggests a new source of evidence for this further distinction: males do better than females on items requiring an addition/subtraction or distribution of two rule, but there is no sex difference on items requiring pairwise progression or distribution of three rules. A specially designed experiment confirmed this pattern of results.