Effects of retinal size on visual laterality

Observers indicated whether two vertically presented bars were aligned one above the other (same trials) or were offset by an amount equal to the width of the bars on that trial (different trials). Retinal size was varied by using bars of three different widths (wide, medium, narrow). On different trials, reaction time to make correct responses was longer for narrow stimuli than for the other two sizes; this size effect was larger when stimuli were projected to the right visual field than when stimuli were projected to the left visual field. Such effects were not found on same trials. Implications of these results are discussed in light of alternative hypotheses about the effects of stimulus input parameters on visual laterality.