The conditions for temporal tracking under interval schedules of reinforcement

On many cyclic-interval schedules, animals adjust their postreinforcement pause to follow the interval duration (temporal tracking). Six pigeons were trained on a series of square-wave (2-valued) interval schedules (e.g., 12 fixed-interval [FI] 60, 4 FI 180). Experiment 1 showed that pigeons track square-wave schedules, except those with a single long interval per cycle. Experiments 2 and 3 established that tracking and nontracking are learned and both can transfer from one cyclic schedule to another. Experiment 4 demonstrated that pigeons track a schedule with a single short interval per cycle, suggesting that a dual process--cuing and tracking--is necessary to explain behavior on these schedules. These findings suggest a potential explanation for earlier results that reported a failure to track square-wave schedules.