AERs and detection in tasks yielding U-shaped backward masking functions.

Abstract

ABSTRACTIn backward masking, psychophysical performance varies as a function of the interval between target and mask (stimulus onset asynchrony—SOA). Early studies of averaged evoked responses (AERs) and backward masking suggested a close, monotonic relationship, i.e., increasing psychophysical performance accompanied by increasingly larger AERs as a function of SOA. We asked what would happen to AERs if the perceptual task were designed to produce a U‐shaped performance function, i.e., one in which performance initially decreased and then increased as a function of SOA? In two experiments U‐shaped psychophysical performance was accompanied by monotonic AER functions. In a third experiment, comparing backward and forward masking at comparable SOAs, disparate psychophysical performances were obtained from the same subjects accompanied by similar AERs. Target AERs do not necessarily correlate with a subject's behavioral performance.