The ability of two internal clock models to predict performance on a temporal bisection procedure

Abstract

This research is a replication of Machado and Keen’s (1999) procedure which tested the ability of two competing models of animal timing; Learning to Time (LET) and Scalar Expectancy Theory (SET), to predict pigeons performance on a temporal bisection task. Hens were trained in two temporal discrimination's; in Type 1 trials they learned to choose a red key after a 1-s signal and a green key after a 4-s signal and in Type 2 trials they learned to choose a green key after a 4-s signal, and a yellow key after a 16-s signal to receive access to reinforcement. After they learnt these discriminations, intermediate durations were presented. The resulting psychometric function did not superpose, violating the scalar property of timing. When novel key and duration combinations were presented, performance on subsequent generalisation tests closely matched LET’s predictions. Overall, the results support the findings of Machado and Keen (1999) and supported LET’s rather than SET’s predictions.