Perceptual and memory components of the superior recall of letters from the right visual half-fields

Abstract

Right-hander's show consistently better recall from the right visual half-field (VHF) when digit sequences are presented simultaneously at fixation and in one of the visual half-fields. This right VHF superiority has been attributed to the more direct connection between the right VHF and the speech areas in the left hemisphere of the brain. The effect of amount of material to be remembered, interstimulas interval, and presentation time was studied in order to assess the importance of short-term memory, backward masking, and perceptual factors on this task. Sequences of five letter pairs were presented at two different interstimulas intervals (165 msec and 330 msec) and three presentation times (165 msec, 280 msec and 330 msec). Increasing the amount of material to be remembered and increasing the interstimulas interval appeared to increase the asymmetry between the VHF's. Changing presentation time (from 330 msec to 165 msec) had little effect on either the VHF asymmetry or recall efficiency. This suggests that the controlled fixation paradigm is a memory and backward masking task with the right VHF superiority resulting primarily from the memory aspect of the task.