Gil Mariana, De Marco Rodrigo J, Menzel Randolf
Free University of Berlin, Department of Biology/Chemistry/Pharmacy, Institute of Biology/Neurobiology, Berlin, Germany.
Learn Mem. 2007 Jul 12;14(7):491-6. doi: 10.1101/lm.618907. Print 2007 Jul.
The aim of this study was to test whether honeybees develop reward expectations. In our experiment, bees first learned to associate colors with a sugar reward in a setting closely resembling a natural foraging situation. We then evaluated whether and how the sequence of the animals' experiences with different reward magnitudes changed their later behavior in the absence of reinforcement and within an otherwise similar context. We found that the bees that had experienced increasing reward magnitudes during training assigned more time to flower inspection 24 and 48 h after training. Our design and behavioral measurements allowed us to uncouple the signal learning and the nutritional aspects of foraging from the effects of subjective reward values. We thus found that the animals behaved differently neither because they had more strongly associated the related predicting signals nor because they were fed more or faster. Our results document for the first time that honeybees develop long-term expectations of reward; these expectations can guide their foraging behavior after a relatively long pause and in the absence of reinforcement, and further experiments will aim toward an elucidation of the neural mechanisms involved in this form of learning.
本研究的目的是测试蜜蜂是否会形成奖励预期。在我们的实验中，蜜蜂首先在一个与自然觅食情境非常相似的环境中学会将颜色与糖奖励联系起来。然后，我们评估了动物在经历不同奖励幅度的过程中，其经历顺序是否以及如何在没有强化的情况下，在其他方面相似的情境中改变它们随后的行为。我们发现，在训练过程中经历奖励幅度增加的蜜蜂，在训练后24小时和48小时会将更多时间用于花朵检查。我们的设计和行为测量使我们能够将信号学习和觅食的营养方面与主观奖励值的影响分离开来。因此，我们发现动物的行为差异既不是因为它们更强地将相关预测信号联系起来，也不是因为它们被喂食得更多或更快。我们的结果首次证明蜜蜂会形成对奖励的长期预期；这些预期可以在相对较长的停顿后且没有强化的情况下指导它们的觅食行为，进一步的实验将旨在阐明这种学习形式所涉及的神经机制。
