Can an analytic/holistic dichotomy explain hemispheric asymmetries?

Same RTs to pairs of letters or other patterns are often faster than different RTs. This finding has led to hypothesize a two-process system of comparison: a fast holistic process for same and a slower analytic process for different responses. In connection with hemispheric specialization, RH has been characterized as a holistic and LH as an analytic processor. Therefore same responses should be mediated by RH and different responses by LH. In the present study, subjects made same-different judgments in the two visual fields to successively presented pairs of letters where degree of difference was systematically varied. RTs decreased with increases in the degree of difference in different responses. Same responses were faster than different. These results suggest analytic processing of different and holistic processing of same pairs. Since no clear-cut visual field superiority was found, the conclusion is that both hemispheres can process visual information analytically and holistically.