Perception of similarity and laterality effects in tactile shape recognition.

Similarity judgements were made about pairs of shapes explored haptically with the hands moving in the same (congruent), or opposite direction. Scanning shapes using an opposite manual direction was slower and less accurate. These results enabled stimulus selection for a further experiment that examined laterality effects in the haptic modality. Pairs of shapes were explored and the presence/absence of a target shape indicated using a pedal switch. Males showed a right hand disadvantage, whereas females were equally accurate at recognising target shapes with either hand, and were equivalent to males' left hand recognition accuracy. Direction of hand movements (congruent vs opposite) and target type also interacted with sex. These interactions and the 1-2 sec longer decision time by females suggest sex differences in the use of cognitive strategies rather than in hemispheric specialization of function.