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We used a midsession reversal task to investigate how temporal and situational cues may combine to determine choice in frequently changing environments. Pigeons learned a simultaneous discrimination with 2 stimuli: S1 and S2. Choices of S1 were reinforced only during the first trials, and choices of S2 were reinforced only during the last trials of the session, that is, the reinforcement contingencies reversed once during the session. To weaken the temporal cue (time into the session) that signaled the reversal trial, we varied the location of reversal trial randomly across sessions; to weaken the situational cue (the outcome of the previous trials that might support a win-stay/loose shift strategy), we varied the payoff probabilities associated with S1 and S2. Performance was consistent neither with the exclusive use of a timing strategy, nor with the exclusive use of a situational, win-stay/lose-shift strategy. Instead, choice seemed to be under joint control of both cues. The relative influence of these cues was dynamic: When payoff was higher for S1 than S2, behavior was less time-controlled than when the payoff was higher for S2 that S1, or when they were equal. We advance a descriptive mixture model of joint control for the midsession reversal task. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Using signal detection theory, we investigated whether human participants represent time linearly or logarithmically in a bisection task. Participants saw a stimulus 1.0 to 1.5 s in duration, and then judged whether the stimulus duration was closer to 1.0 s or to 1.5 s, and how sure they were of their response. Whereas the mean of the subjective stimulus duration was a linear function of the objective stimulus duration, participants produced remarkably different psychophysical functions-linear for some participants, concave for others, and convex for still others. Hence, the appropriate question might not be whether humans encode time linearly or logarithmically, but for which participants and under which conditions is time encoded linearly, logarithmically, or even exponentially. (PsycINFO Database Record (c) 2018 APA, all rights reserved). 44