When given the opportunity, chimpanzees maximize personal gain rather than "level the playing field".
When given the opportunity, chimpanzees maximize personal gain rather than "level the playing field".
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作者：
Hopper LM;Lambeth SP;Schapiro SJ;Brosnan SF
我们为黑猩猩（Pan troglodytes）提供了提高食物质量的能力，他们在一个不平等的二元测试中获得了奖励。我们有兴趣看看这一规定是否影响他们的反应，如果是这样，它是否是由社会伙伴的结果介导。我们使用交换范式测试了八对黑猩猩，根据条件的不同，黑猩猩在每次完成交换时都会获得高价值（一颗葡萄）或低价值（一片芹菜）的食物奖励。我们提出了四个条件。在第一个“不同”的条件下，受试者在每次交换中得到的奖励都与他们的伴侣不同，而且不那么受欢迎（这是一个不公平的测试）。在“不可用”的条件下，在每次交换之前，向两只黑猩猩展示了高价值的奖励，但没有给予黑猩猩，并且黑猩猩同样获得了低价值的奖励（个体对比测试）。最后两个条件创造了公平。在这些高价值和低价值“相同”的条件下，两个黑猩猩在每次交换中都得到了相同的食物奖励。在每种条件下，黑猩猩首先在基线阶段完成10次试验，在此期间，实验者确定他们获得的奖励，然后在测试阶段完成10次试验。在测试阶段，黑猩猩可以通过挂在笼子网眼上的一个小木制相框的小孔交换代币，以获得高价值的奖励。因此，在测试阶段，黑猩猩有机会提高他们所获得的奖励的质量，无论是绝对的还是相对于他们的伴侣所获得的。黑猩猩以有针对性的方式做出反应;在测试阶段，它们试图在基线阶段获得低价值奖励的所有条件下最大化回报。因此，黑猩猩显然有动机增加他们的奖励，而不管他们的伙伴，但他们只使用提供的机制，当它提供了机会，以增加他们的奖励。我们还发现证据表明，黑猩猩的反应是由社会促进增强。具体来说，黑猩猩更有可能通过框架交换他们的代币，当他们的测试伙伴也这样做时，即使在他们的奖励价值无法提高的情况下。我们的范式为黑猩猩提供了提高他们在测试阶段获得的奖励质量的可能性。我们发现，与基线阶段相比，测试阶段的拒绝-交换代币或吃奖励-显着减少，其中不存在改善结果的机会。因此，当黑猩猩能够提高他们获得的奖励时，他们会更多地参与。
We provided chimpanzees (Pan troglodytes) with the ability to improve the quality of food rewards they received in a dyadic test of inequity. We were interested to see if this provision influenced their responses and, if so, whether it was mediated by a social partner’s outcomes. We tested eight dyads using an exchange paradigm in which, depending on the condition, the chimpanzees were rewarded with either high-value (a grape) or low-value (a piece of celery) food rewards for each completed exchange. We included four conditions. In the first, “Different” condition, the subject received different, less-preferred, rewards than their partner for each exchange made (a test of inequity). In the “Unavailable” condition, high-value rewards were shown, but not given, to both chimpanzees prior to each exchange and the chimpanzees were rewarded equally with low-value rewards (a test of individual contrast). The final two conditions created equity. In these High-value and Low-value “Same” conditions both chimpanzees received the same food rewards for each exchange. Within each condition, the chimpanzees first completed ten trials in the Baseline Phase, in which the experimenter determined the rewards they received, and then ten trials in the Test Phase. In the Test Phase, the chimpanzees could exchange tokens through the aperture of a small wooden picture frame hung on their cage mesh in order to receive the high-value reward. Thus, in the Test Phase, the chimpanzees were provided with an opportunity to improve the quality of the rewards they received, either absolutely or relative to what their partner received. The chimpanzees responded in a targeted manner; in the Test Phase they attempted to maximize their returns in all conditions in which they had received low-value rewards during the Baseline Phase. Thus, the chimpanzees were apparently motivated to increase their reward regardless of their partners’, but they only used the mechanism provided when it afforded the opportunity for them to increase their rewards. We also found evidence that the chimpanzees’ responses were enhanced by social facilitation. Specifically, the chimpanzees were more likely to exchange their tokens through the frame when their test partner also did so, even in circumstances in which their reward value could not be improved. Our paradigm provided the chimpanzees with the possibility to improve the quality of rewards they received in the Test Phase. We found that refusals – to exchange tokens or to eat rewards – decreased significantly in the Test Phase compared to the Baseline Phase, where no such opportunity for improvement of outcomes existed. Thus, the chimpanzees participated more when they could improve the rewards they received.
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影响因子：
2.5
作者：
Galef, Bennett G.;Whiskin, Elain E.
通讯作者：
Whiskin, Elain E.
影响因子：
2.5
作者：
Alberts, SC;Altmann, J;Wilson, ML
通讯作者：
Wilson, ML
DOI：
10.1098/rstb.2009.0060
发表时间：
2009-08-27
影响因子：
6.3
作者：
Huber, Ludwig;Range, Friederike;Miklosi, Adam
通讯作者：
Miklosi, Adam
影响因子：
2.5
作者：
Hopper, Lydia M.;Spiteri, Antoine;Whiten, Andrew
通讯作者：
Whiten, Andrew
影响因子：
2.4
作者：
Murray, Carson M.;Eberly, Lynn E.;Pusey, Anne E.
通讯作者：
Pusey, Anne E.