Fresh fields and postures new: a discussion paper.

By their very nature, studies of visual hemifield differences in normals are biased toward the discovery of hemispheric asymmetries that occur early in visual processing, and may consequently give a narrow and distorted view of human laterality as a cultural and evolutionary phenomenon. One saving factor, however, is that hemifield differences may in some cases actually represent differences between the two sides of phenomenal space, and thus represent cerebral asymmetries at a relatively late stage in processing. It may therefore be important to develop techniques for distinguishing retinal effects from higher order spatial ones.