Latent timing in human conditioned avoidance.

Four experiments explored signal timing in human conditioned avoidance. Participants received discrimination training with different duration signals that announced the outcome (S+) or not (S-). Temporal discrimination and superposition of performance to S+ signals of different length (3, 6, or 9 s) was found both in within-subjects (Experiment 1a) and between-subjects (Experiment 1b) designs. S- signals also produced a temporal discrimination and superposition effect during a single test trial conducted after the meaning of the signals was reversed through instructions. Experiments 2a and 2b replicated these results in a situation in which (a) the durations of the S+ and S- signals were different (4.5 or 9 s) to prevent any temporal generalization between them (Experiment 2a), and (b) only S- signals were presented during training, precluding developing of inhibition to S- (Experiment 2b). These results show that participants time both S+ and S- signals in human conditioned avoidance, and they further suggest that the timing of a cue is independent of reinforcement.