Fig. 4.

Mean percentage of maximum defection rate (across all trials, as defection occurs at a maximum of once per trial) as a function of signal duration (s) for all rats combined. The data indicate a tri-modal distribution with the first defection point occurring prior to the 10-s target duration, the second occurring between the two target durations at approximately the geometric mean (e.g., 20 s), and the last occurring after the 40-s target duration (panel A). Probability of defecting if this time point is reached (i.e., if the trial has not already ended due to prior defection or 40-s FI reinforcement (panel B).