Critical stimulus durations for some verbal and nonverbal stimuli

Durations of stimulus exposures in visual backward masking are determined with reference to critical stimulus durations. These are defined as the minimum, undisrupted, durations of exposure for 100% accuracy for a predetermined number of trials. These durations are shown to vary both within and between classes of stimuli for 10 normal adults with a mean age of 26.40 yr. The verbal stimuli employed (letters of the alphabet) were significantly easier to discern than the nonverbal stimuli (arrows). Although some letters were more readily identified than others, differences were not significant. The results suggest that type of stimuli, nature of response, and the ease with which stimuli can be discerned be considered in the selection of target stimuli for experiments using masking.