Chimpanzees (Pan troglodytes) can wait, when they choose to: a study with the hybrid delay task
Chimpanzees (Pan troglodytes) can wait, when they choose to: a study with the hybrid delay task
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DOI：
10.1007/s10071-013-0652-9
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发表时间：
2014-03-01
期刊：
影响因子：
2.7
通讯作者：
Hopkins, William D.
中科院分区：
文献类型：
--
作者：
Beran, Michael J.;Evans, Theodore A.;Hopkins, William D.
人们已经通过各种任务对非人类动物的自我控制进行了研究。跨期选择（ITC）任务提供了较小较早（SS）和较大较晚（LL）选项之间的选择。使用食物量作为奖励，这会带来两个问题：(a) LL 选项的选择要么反映了自我控制，要么是由于动物难以指出较小的食物量； (b) 如果在随后的延迟期间有机会这样做，则无法验证受试者是否不会恢复对 LL 选项的选择。为了解决这些问题，我们最近引入了一种新的协议，即混合延迟任务，它将初始 ITC 与随后的积累阶段相结合，其中选择 SS 选项会导致其立即交付，但选择 LL 选项则会导致这些项目的逐一呈现，只有当受试者不吃任何积累的项目时才会继续。因此，当在积累阶段从 LL 选择中获得的项目数量高于 SS 选项中可以获得的项目数量时，LL 选项的选择仅反映自我控制。先前对卷尾猴的研究表明，鉴于它们在混合延迟任务中的表现不佳，它们在 ITC 任务中的明显自我控制反应可能高估了它们的一般自我控制能力。在这里，黑猩猩反而证明了它们在混合延迟任务的 ITC 阶段对 LL 选项的选择是通过它们在 LL 奖励积累过程中维持长时间延迟的能力得到证实的。
Self-control has been studied in nonhuman animals using a variety of tasks. The inter-temporal choice (ITC) task presents choices between smaller-sooner (SS) and larger-later (LL) options. Using food amounts as rewards, this presents two problems: (a) choices of the LL option could either reflect self-control or instead result from animals' difficulty with pointing to smaller amounts of food; (b) there is no way to verify whether the subjects would not revert their choice for the LL option, if given the opportunity to do so during the ensuing delay. To address these problems, we have recently introduced a new protocol, the hybrid delay task, which combines an initial ITC with a subsequent accumulation phase in which selection of the SS option leads to its immediate delivery, but choice of the LL option then leads to one-by-one presentation of those items that continues only as long as the subject does not eat any of the accumulated items. The choice of the LL option therefore only reflects self-control when the number of items obtained from LL choices during the accumulation phase is higher than what could be received in the SS option. Previous research with capuchin monkeys demonstrated that their apparent self-control responses in the ITC task may have overestimated their general self-control abilities, given their poor performance in the hybrid delay task. Here, chimpanzees instead demonstrated that their choices for the LL option in the ITC phase of the hybrid delay task were confirmed by their ability to sustain long delays during accumulation of LL rewards.