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.