Spatial relations and object processes in two cerebral hemispheres: A validation of a sequential matching paradigm for the study of laterality

Abstract

Kosslyn (1987) proposed that categorical spatial relations (i.e., above/below) would be processed more effectively in the left hemisphere, whereas coordinate or metric relations would be processed more effectively in the right hemsphere. To examine his hypothesis, a sequential matching task adopted by Laeng and Peters (1995) was administered. In this task, a sample stimulus was presented in the central visual field and it was followed by a match stimulus presented briefly in the left or right visual field. In Experiment 1, the participants' task was a same– different discrimination about spatial relations. Participants responded faster to categorical changes in the right visual field presentation. This result was consistent with Kosslyn's hypothesis. In Experiment 2, participants were asked to make same–different judgements about objects (either a digit or a natural line drawing) irrespective of spatial location. They responded faster to digit (i.e., verbal) changes in the right visual field. This result was compatible with the classical notion that verbal materials would be processed more effectively in the left hemisphere. This evidence suggests that the matching paradigm of the present study is useful for investigating cerebral lateralisation not only for spatial relations but also for object processes.