Hemispheric asymmetries in mediating intention, but not selective attention.

Heilman and Van Den Abell [Neuropsychologia 17, 315-321, 1979] reported a right hemisphere dominance for cerebral activation. In the present study, we further examined the nature of this finding in an experimental paradigm in which selective attention and intention (response readiness) were manipulated independently. Normal subjects were tested on a choice reaction time task in which they were given preliminary information about where a target stimulus would occur (selective attention) and which hand to use for responding (intention). Our findings indicate that at short foreperiod durations, the right hemisphere is superior for mediating intention. There was no evidence for a right hemisphere superiority for selective attention.