Gender differences in personality: Biological and/or psychological?

The results of three empirical studies are reported in which the hypothesis is tested that differences in personality variables between the morphophenotype sexes can be explained by psychological sex-role orientation variables. Furthermore, it was expected that normative sex-role orientations (measured with the SRO-S and the AWS-S Scales) and gender-related self-concepts (femininity, masculinity, and androgyny measured with a modified BSRI) explain more variance in personality variables than morphophenotype sex. Besides these sex-role orientation variables, test and questionnaire data on verbal fluency, spatial reasoning, self-concept, anxiety, and aggressiveness were obtained in Study I from 50 young adults and their same-sex parents; in Study II, data on verbal fluency, spatial reasoning, self-concept, anxiety, and neuroticism were obtained from 120 university students; and in Study III, data on anxiety, locus of control, and Machiavellianism were obtained from 226 university students. The results confirm both hypotheses for the two aspects of intelligence studied, domain-specific self-concepts, different aspects of anxiety and aggressiveness, neuroticism, powerful others' externality in locus of control, and Machiavellianism. For all these personality variables the effect sizes of the psychological gender variables were larger than those of morphophenotype sex and reached medium to large values.     

Spatial frequency content of visual imagery

Three experiments employing the McCollough paradigm were conducted to determine the spatial-frequency content of visual imagery. In Experiment 1, large and reliable pattern-contingent color aftereffects were obtained after adaptation to visual imagery. The direction of the aftereffects indicated that subjects were adapting to higher spatial frequencies in their imagery. These results contrast with the data of Experiment 2, which demonstrate that color aftereffects obtained with adaptation to physically present stimuli are mediated by the fundamental spatial frequency components. The magnitude of the imagery-induced aftereffects in Experiment 1 equaled the magnitude of the externally induced aftereffects obtained in Experiment 2 with the same subjects. By blurring the to-be-imaged patterns (Experiment 3), the fundamental Fourier components became the salient perceptual features of the stimuli, and the direction of the imagery-induced aftereffects was reversed from that of Experiment 1, indicating that the spatial frequency content of the imagery had changed from higher to lower frequencies. Under normal viewing conditions, subjects use the higher spatial frequencies associated with the perceptually salient edges of stimuli to construct their images. The results of Experiments 1 and 3 are discussed in light of a current controversy over the nature of information representation in imagery, and it is concluded that support has been obtained for the analog model of visual imagery.     

Path integration while ignoring irrelevant movement

Participants attempted to return to the origin of travel after following an outbound path by locomotion on foot (Experiments 1-3) or in a virtual visual environment (Experiment 4). Critical conditions interrupted the outbound path with verbal distraction or irrelevant, to-be-ignored movements. Irrelevant movement, real or virtual, had greater effects than verbal or cognitive distraction, indicating inability to ignore displacement during path integration. Effects of the irrelevant movement's direction (backward vs. rightward) and location (1st vs. 2nd leg of path) indicated that participants encoded a configural representation of the pathway and then cognitively compensated for the movement, producing errors directly related to the demands of compensation. An encoding-error model fit to the data indicated that backward movement produced downward rescaling, whereas movement that led to implied rotation (rightward on 2nd leg) produced distortions of shape and scale.     

Platelet MAO-B, personality, and psychopathology

The article investigates the relationships between platelet monoamine oxidase-B (MAO-B) activity, personality, and psychopathology (Diagnostic and Statistical Manual of Mental Disorders [4th ed.; American Psychiatric Association, 1994] diagnoses. These relationships were assessed in 178 incarcerated male juvenile delinquents. Even after controlling for smoking, the authors found that both Internalizing and Externalizing Psychopathology were negatively related to MAO-B activity. In the final reduced model, novelty seeking fully mediated the relationships between MAO-B and Externalizing Psychopathology but not between MAO-B and Internalizing Psychopathology. It was hypothesized that low platelet MAO-B activity does not directly predispose individuals to psychopathology but is related to specific personality traits, which in turn represent a vulnerability factor for psychopathology. Future studies should help clarify the nature of the relationships between personality, biological markers, and psychopathology.