The ephemeral reward task consists of giving an animal a choice between two distinctive stimuli, A and B (e.g., black and white), on each of which is placed a bit of food. If the animal chooses the food on A, it gets that reinforcer, but the other stimulus, B, is removed, and the trial is over. If it chooses the food on B, however, it gets that food and the stimulus A remains, so it can have that food as well. Thus, choice of stimulus B gives the animal two reinforcers rather than one. Wrasse (cleaner fish) easily learn to choose optimally, whereas surprisingly, most non-human primates do not. Parrots, however, appear to learn this task as easily as the fish. To test the hypothesis that animals that choose with their mouth can learn it, we tested pigeons and found that they show no evidence of optimal learning with this task (with either the manual presentation of the stimuli or the operant presentation of the stimuli). Similarly, rats show no evidence of optimal learning. However, if a 20-s delay (fixed-interval schedule) is inserted between stimulus choice and reinforcement, both pigeons and rats learn to perform optimally. The ephemeral reward task appears to promote impulsive choice in several species, but with this task (and others), inserting a delay between choice and reinforcement promotes more careful choice, leading to optimal performance.

短暂的奖励任务包括给动物一个在两个独特的刺激A和B（例如，黑色和白色）之间进行选择的选择，每个刺激上都放置一点食物。如果动物选择A上的食物，它将得到增强剂，但另一种刺激B被删除，试验结束。但是，如果选择B上的食物，它将得到食物，而刺激A仍然存在，因此它也可以拥有食物。因此，刺激B的选择为动物提供了两种增强剂，而不是一种。濑鱼（清洁鱼）很容易学会最佳选择，而令人惊讶的是，大多数非人类灵长类动物却没有。然而，鹦鹉似乎像鱼一样容易学习这项任务。为了检验动物的嘴巴可以学习的假设，我们对鸽子进行了测试，发现它们没有显示出可以最佳学习的证据（通过手动呈现刺激或以操作呈现刺激）。同样，大鼠没有显示最佳学习的证据。但是，如果在刺激选择和强化之间插入20 s的延迟（固定间隔时间表），鸽子和老鼠都会学习到最佳表现。短暂奖励任务似乎可以促进几个物种的冲动选择，但是通过执行此任务（和其他任务），在选择和强化之间插入延迟可以促进更谨慎的选择，从而实现最佳性能。鸽子和老鼠都学会了最佳表现。短暂奖励任务似乎可以促进几个物种的冲动选择，但是通过执行此任务（和其他任务），在选择和强化之间插入延迟可以促进更谨慎的选择，从而实现最佳性能。鸽子和老鼠都学会了最佳表现。短暂奖励任务似乎可以促进几个物种的冲动选择，但是通过执行此任务（和其他任务），在选择和强化之间插入延迟可以促进更谨慎的选择，从而实现最佳性能。