INDIVIDUAL DIFFERENCES IN VISUAL IMAGERY AND SPATIAL ABILITIES

Six experiments were run to investigate individual differences in visual imagery and spatial abilities. The first four (using cognitive methods) involved various reaction time 'mental rotation’ tasks, in an attempt to pinpoint the process(es) underlying the male superiority found in psychometric spatial tasks. It was hypothesised that sex differences might be found in slope of the mental rotation task (assumed to represent speed of mental rotation, while intercept represents encoding, comparison and response), However, a male superiority was only found in Experiment IV, and in intercept, not in slope. Therefore a combined cognitive/differential approach was used in the last two experiments. In addition to the RT mental rotation task, subjects completed a battery of spatial and verbal psychometric tests, and imagery and other self-report questionnaires. Sex differences in intercept were found in both experiments, but in slope only in the last. Although when the five experiments for which slope and intercept were calculated were combined, significant sex differences in slope were apparent overall, this effect was obviously much weaker than had been suggested in the literature. However, contrary to previously reported findings, sex differences in intercept did appear in three out of the five experiments. In factor analyses of the last two experiments, intercept loaded with the spatial factor in both, whereas slope did so only in one. Explanations are offered in terms of the complexity of the stimuli. This also may be the cause of variations in steepness of slope in the five experiments, which is discussed in terms of the Analogue/Propositional debate. With regard to self-report imagery questionnaires, apart from one "control of imagery" questionnaire which loaded on the spatial factor in one experiment, these loaded exclusively on their own factor. This provides some evidence for the independence of self-rating questionnaires and "objective' performance tests