Humans and other animals have been shown to exhibit preferences for options previously associated with greater past need. Such studies indicate that animals are sensitive to both the physical properties of choices and their own state-dependent gains at the time of learning. Because this behaviour appears to occur across divergent taxonomic groups, it most likely reflects a common way that animals learn about food. Here we study this phenomenon in the frog-eating bat, Trachops cirrhosus. This carnivorous bat hunts by eavesdropping on frog and insect mating calls and its diet is both broad and seasonally variable. As a result, these bats must learn about new sources of food and possibly the state-dependent gains associated with those sources. In this experiment we trained bats to associate two different acoustic cues (ringtones) to two identical food rewards. Each ringtone was encountered in one of two nutritional states: hungry or pre-fed. We then tested preferences between these cues under both nutritional states. We found that bats overwhelmingly preferred the ringtone associated with previous greater deprivation regardless of their condition during testing. We argue that it is most likely adaptive for frog-eating bats to place a higher value on food rewards that are obtained when internal reserves are low.

中文翻译：

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状态依赖学习影响声学捕食者的觅食行为

人类和其他动物已被证明对以前与更大的过去需求相关的选择表现出偏好。此类研究表明，动物在学习时对选择的物理特性和它们自己的状态相关增益都很敏感。因为这种行为似乎发生在不同的分类群中，所以它很可能反映了动物学习食物的一种常见方式。在这里，我们在吃青蛙的蝙蝠 Trachops cirrhosus 中研究这种现象。这种肉食性蝙蝠通过窃听青蛙和昆虫的交配叫声来捕食，它的饮食范围广泛且随季节变化。因此，这些蝙蝠必须了解新的食物来源，以及与这些来源相关的可能依赖于国家的收益。在这个实验中，我们训练蝙蝠将两种不同的声音提示（铃声）与两种相同的食物奖励联系起来。每个铃声都处于两种营养状态之一：饥饿或预先喂食。然后，我们测试了两种营养状态下这些线索之间的偏好。我们发现，无论在测试期间的状况如何，蝙蝠都非常喜欢与先前更严重的剥夺相关的铃声。我们认为，吃蛙的蝙蝠最有可能对内部储备低时获得的食物奖励给予更高的重视。我们发现，无论在测试期间的状况如何，蝙蝠都非常喜欢与先前更严重的剥夺相关的铃声。我们认为，吃蛙的蝙蝠最有可能对内部储备低时获得的食物奖励给予更高的重视。我们发现，无论蝙蝠在测试期间的状况如何，他们都非常喜欢与先前更严重的剥夺相关的铃声。我们认为，吃蛙的蝙蝠最有可能对内部储备低时获得的食物奖励给予更高的重视。