The pattern of responding in the peak-interval procedure with gaps: an individual-trials analysis.
Humans and lower animals time as if using a stopwatch that can be "stopped" or "reset" on command. This view is challenged by data from the peak-interval procedure with gaps: Unexpected retention intervals (gaps) delay the response function in a seemingly continuous fashion, from stop to reset. We evaluated whether these results are an artifact of averaging over trials, or whether subjects use discrete alternatives or a continuum of alternatives in individual-trials: A Probability-of-Reset hypothesis proposes that in individual gap trials subjects stochastically use discrete alternatives (stop/reset), such that when averaged over trials, the response distribution in gap trials falls in between "stop" and "reset." Alternatively, a Resource Allocation hypothesis proposes that during individual gap trials working memory for the pregap duration decays, such that the response function in individual gap trials is shifted rightward in a continuous fashion. Both hypotheses provided very good fits with the observed individual-trial distributions, although the Resource Allocation hypothesis generated reliably better fits. Results provide support for the usefulness of individual-trial analyses in dissociating theoretical alternatives in interval timing tasks.
Swearingen
Joshua E
JE
Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA.
Buhusi
Catalin V
CV
D000465:Algorithms; D000818:Animals; D001683:Biological Clocks; D003216:Conditioning, Operant; D003627:Data Interpretation, Statistical; D004193:Discrimination Learning; D008960:Models, Psychological; D011597:Psychomotor Performance; D051381:Rats; D011930:Reaction Time; D013998:Time Perception