Hemispheric asymmetry: a signal detection analysis.

Subjects were asked to indicate, by a simple motor response, the presence or absence of a predesignated target letter in unilaterally presented consonant trigrams. Perceptual sensitivity (d') was signficantly greater in the right visual hemifield and did not depend upon hand of response. Reaction times were slightly higher in the left hemifield and for the left hand. Response bias (beta) did not differ between hemifields. Models of perceptual asymmetry as a consequence of information loss transcallosally are weakened by the results.