Trial frequency effects in human temporal bisection : implications for theories of timing.

To contrast the classic version of the Scalar Expectancy Theory (SET) with the Behavioral Economic Model (BEM), we examined the effects of trial frequency on human temporal judgments. Mathematical analysis showed that, in a temporal bisection task, SET predicts that participants should show almost exclusive preference for the response associated with the most frequent duration, whereas BEM predicts that, even though participants will be biased, they will still display temporal control. Participants learned to emit one response (R[S]) after a 1.0-s stimulus and another (R[L]) after a 1.5-s stimulus. Then the effects of varying the frequencies of the 1.0-s and 1.5-s stimuli were assessed. Results were more consistent with BEM than with SET. Overall, this research illustrates how the impact of non-temporal factors on temporal discrimination may help us to contrast associative models such as BEM with cognitive models such as SET. Deciding between these two classes of models has important implications regarding the relations between associative learning and timing. This article is part of a Special Issue entitled: Associative and Temporal Learning.
This research was supported by NIH grant MH033881. Jeremie Jozefowiez and Armando Machado acknowledge support from the Fundacao para a Ciencia e a Tecnologia as well as from the European project COST ISCH Action TD0904 "Time in Mental activity" (www.timely-cost.eu). We would like to thank Sean Gannon and Sarah Sterling for help running parts of the experiments, Mario Laborda, Bridget McConnell, Gonzalo Miguez, and James Witnauer for comments on an earlier version of this manuscript. Correspondence concerning this article should be addressed to Jeremie Jozefowiez, laboratoire URECA, Universite Lille Nord de France, Campus de Lille3, Domaine Universitaire du Pont de Bois, BP 60149, 58653 Villeneuve d'Ascq Cedex, France. jeremie.jozefowiez@univ-lille3fr.