The influence of lateralized pointing on spatial relation processing

Abstract

Our cognition interacts continuously with the environment, which is for example shown by effects of prism adaptation. Recently, two studies found out that pointing to one side of the visual field produces similar alterations as prism adaptation in pointing straight ahead and a local/global processing task, an attentional process which is strongly lateralized in the brain. Current study examined the effects of this so called lateralized pointing (LP) on spatial relation processing, which also has a strong lateralization pattern. Categorical relations are mainly processed in the left hemisphere and the right hemisphere is primarily involved with coordinate processing. Therefore, it was hypothesized that right LP improves performance on a categorical task and left LP improves performance on a coordinate task. Students from Utrecht University performed a cross-dot task both before and after LP. In order to control for possible effects of tiredness or practice, some participants performed the cross-dot task twice, but without intermediate pointing. Results showed that regardless of pointing direction, performance on the categorical task improved as a result of LP, while coordinate processing did not differ as a result of LP. Given these results, it is likely that the left hemisphere is activated as a result of a sensorimotor process which consequently activated left superior parietal lobe, rather than an attentional bias to one side of the visual field.