We examined how biasing time perception affects choice in a midsession reversal task. Given a simultaneous discrimination between stimuli S1 and S2, with choices of S1 reinforced during the first, but not the second half of the trials, and choices of S2 reinforced during the second, but not the first half of the trials, pigeons show anticipation errors (premature choices of S2) and perseveration errors (belated choices of S1). This suggests that choice depends on timing processes, on predicting when the contingency reverses based on session duration. We exposed 7 pigeons to a midsession reversal task and manipulated the reinforcement rate on each half of the session. Compared to equal reinforcement rates on both halves of the session, when the reinforcement rate on the first half was lower than on the second half, performance showed more anticipation and less perseveration errors, and when the reinforcement rate on the first half was higher than on the second half, performance showed a remarkable reduction of both types of errors. These results suggest that choice depends on both time into the session and the outcome of previous trials. They also challenge current models of timing to integrate local effects.

Zentall's (2019) target article, "What suboptimal choice tells us about the control of behavior," is in three parts. The first part reviews a set of studies that have yielded surprising findings: In relatively simple choice tasks, animals seem to behave irrationally by making suboptimal choices. The second part introduces a set of hypotheses to account for the surprising findings: Animals may behave according to a variety of heuristics that are adaptive in their natural environments but maladaptive in the contrived laboratory settings. The third part explains what suboptimal choice in fact tells us about the control of behavior. In this commentary we argue that Part 1 is timely, interesting, and important; that Part 2, potentially the article's greatest contribution, includes imaginative, testable hypotheses alongside conceptually confused and even inconsistent hypotheses; and that Part 3 may be too vague to be useful. We conclude with some general remarks on the nature of the problems brought to our attention by the target article.

Our goal was to assess the role of timing in pigeons' performance in the midsession reversal task. In discrete-trial sessions, pigeons learned to discriminate between 2 stimuli, S1 and S2. Choices of S1 were reinforced only in the first half of the session and choices of S2 were reinforced only in the second half. Typically, pigeons choose S2 before the contingency reverses (anticipatory errors) and S1 after (perseverative errors), suggesting that they time the interval from the beginning of the session to the contingency reversal. To test this hypothesis, we exposed pigeons to a midsession reversal task and, depending on the group, either increased or decreased the ITI duration. We then contrasted the pigeons' performance with the predictions of the Learning-to-Time (LeT) model: In both conditions, preference was expected to reverse at the same time as in the previous sessions. When the ITI was doubled, pigeons' preference reversal occurred at half the trial number but at the same time as in the previous sessions. When the ITI was halved, pigeons' preference reversal occurred at a later trial but at an earlier time than in the previous sessions. Hence, pigeons' performance was only partially consistent with the predictions of LeT, suggesting that besides timing, other sources of control, such as the outcome of previous trials, seem to influence choice.