In the midsession reversal task, pigeons are trained on a simultaneous two-alternative discrimination in which S1 is correct for the first half of the session and S2 is correct for the second half of the session. Optimally, pigeons should choose S1 until it stops being correct and choose S2 afterward. Instead, pigeons anticipate S2 too early and continue choosing S1 even after the reversal. Research suggests that they attempt to time the reversal rather than use the feedback from the preceding response(s). Recently, there is evidence that performance is almost optimized by generating an asymmetry between S1 and S2. For example, pigeons’ accuracy improves if correct S1 responses are reinforced 100% of the time, but correct S2 responses are reinforced only 20% of the time. Similarly, accuracy improves if S1 requires one peck but S2 requires 10 pecks. Accuracy does not improve, however, if the value of S1 is less than the value of S2. In the current experiment, we manipulated the magnitude of reinforcement. For the experimental group, correct responses to S1 were reinforced with five pellets of food and correct responses to S2 were reinforced with one pellet. For the control group, all correct responses were reinforced with three pellets. Consistent with the earlier findings, results indicated that there was a significant reduction in anticipatory errors in the experimental group compared with the control, and there was no significant increase in perseverative errors.

在赛中逆转任务中，鸽子接受同时进行的两种交替辨别训练，其中 S1 在前半场比赛中是正确的，S2 在后半场比赛中是正确的。最理想的情况是，鸽子应该选择 S1 直到它不再正确，然后再选择 S2。相反，鸽子过早地预测 S2 并在逆转之后继续选择 S1。研究表明，他们试图为逆转计时，而不是使用来自先前反应的反馈。最近，有证据表明性能几乎可以通过在 S1 和 S2 之间产生不对称来优化。例如，如果正确的 S1 反应在 100% 的时间内得到强化，鸽子的准确度就会提高，但正确的 S2 反应只有 20% 的时间得到强化。同样，如果 S1 需要 1 啄而 S2 需要 10 啄，则精度会提高。但是，如果 S1 的值小于 S2 的值，则精度不会提高。在当前的实验中，我们操纵了强化的幅度。对于实验组，用五粒食物加强对 S1 的正确反应，用一粒食物加强对 S2 的正确反应。对于对照组，所有正确的反应都用三个小球加强。与之前的发现一致，结果表明，与对照组相比，实验组的预期错误显着减少，而坚持错误没有显着增加。对 S1 的正确反应用五粒食物加强，对 S2 的正确反应用一个颗粒加强。对于对照组，所有正确的反应都用三个小球加强。与之前的研究结果一致，结果表明，与对照组相比，实验组的预期错误显着减少，而坚持错误没有显着增加。对 S1 的正确反应用五粒食物加强，对 S2 的正确反应用一个颗粒加强。对于对照组，所有正确的反应都用三个小球加强。与之前的发现一致，结果表明，与对照组相比，实验组的预期错误显着减少，而坚持错误没有显着增加。