Abstract
Varakin, Hays, and Renfro (2015, VSS) demonstrated that stimulus response compatibility (SRC) influences duration judgments. The current experiment tested whether SRC affects an internal timer's rate. Participants (N = 215) performed a temporal bisection task, judging on each trial whether a visual stimulus' duration was closer to pre-learned short or long standards. Response mapping was counterbalanced: about half of participants used a right-hand key for "long" judgments and a left-hand key for "short" judgments, vice versa for remaining participants. On each trial, stimuli appeared on the left or right side of the monitor, thus inducing SRC. Two additional factors were manipulated. The first was the temporal location of the SRC-relevant stimulus. In the "during" condition, the stimulus being judged appeared on the left or the right of fixation. In the "after" condition, the stimulus being judged appeared in the center of the monitor, and the response prompt appeared on the left or right of fixation. If SRC only changes the rate of an internal timer, then SRC might not be observed in the "after" condition, because the relevant temporal interval had ended when SRC was introduced. The third factor was the magnitude of short/long standard durations, which were either 200ms/800ms or 400ms/1600ms. If SRC changes the rate of an internal timer, the SRC effect should be smaller for 200ms/800ms standards than for 400ms/1600ms. The results replicated SRC's influence on temporal bisection: long-compatible stimuli reliably elicited long judgments at shorter durations than short-compatible stimuli. However, SRC was observed even when it was present only after the relevant temporal interval ended, and SRC did not interact with the magnitude of the short and long standards. Overall, these results suggest that SRC did not affect the rate of an internal timer, but may have affected processes otherwise unrelated to time perception.
Meeting abstract presented at VSS 2017