Conditioned stimulus (CS) duration is a determinant of conditioned responding, with increases in duration leading to reductions in response rates. The CS duration effect has been proposed to reflect sensitivity to the reinforcement rate across cumulative exposure to the CS, suggesting that the delay of reinforcement from the onset of the cue is not crucial. Here, we compared the effects of delay and rate of reinforcement on Pavlovian appetitive conditioning in mice. In Experiment 1, the influence of reinforcement delay on the timing of responding was removed by making the duration of cues variable across trials. Mice trained with variable duration cues were sensitive to differences in the rate of reinforcement to a similar extent as mice trained with fixed duration cues. Experiments 2 and 3 tested the independent effects of delay and reinforcement rate. In Experiment 2, food was presented at either the termination of the CS or during the CS. In Experiment 3, food occurred during the CS for all cues. The latter experiment demonstrated an effect of delay, but not reinforcement rate. Experiment 4 ruled out the possibility that the lack of effect of reinforcement rate in Experiment 3 was due to mice failing to learn about the nonreinforced CS exposure after the presentation of food within a trial. These results demonstrate that although the CS duration effect is not simply a consequence of timing of conditioned responses, it is dependent on the delay of reinforcement. The results provide a challenge to current associative and nonassociative, time-accumulation models of learning. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

中文翻译：

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巴甫洛夫条件反射中的强化延迟与强化速率。


条件刺激（CS）持续时间是条件反应的决定因素，持续时间的增加会导致反应率降低。 CS 持续时间效应被提出来反映对 CS 累积暴露期间强化率的敏感性，这表明从提示开始的强化延迟并不重要。在这里，我们比较了延迟和强化速率对小鼠巴甫洛夫食欲调节的影响。在实验 1 中，通过使线索的持续时间在试验中可变，消除了强化延迟对响应时间的影响。用可变持续时间线索训练的小鼠对强化率差异的敏感程度与用固定持续时间线索训练的小鼠相似。实验2和实验3测试了延迟和强化率的独立影响。在实验 2 中，食物在 CS 结束时或 CS 期间提供。在实验 3 中，食物发生在所有线索的 CS 期间。后一个实验证明了延迟的影响，但没有证明强化率的影响。实验 4 排除了实验 3 中缺乏强化率效果是由于小鼠在试验中提供食物后未能了解非强化 CS 暴露的可能性。这些结果表明，虽然 CS 持续时间效应不仅仅是条件反应时间的结果，但它取决于强化的延迟。结果对当前的联想和非联想、时间累积学习模型提出了挑战。 （PsycINFO 数据库记录 (c) 2019 APA，保留所有权利）。