Judgment bias tasks can reveal changes in affect in animals as a function of environmental manipulations such as provision of enrichment. We assessed affect in an American black bear across seasonal changes in availability of a mulberry bush. We used a novel judgment bias task in which the background color of a touchscreen signaled whether the left or right positioned stimulus was correct. The bear learned the conditional rule in which the correct action for the white background (choose left) resulted in three pieces of food and the correct action for the black background (choose right) resulted in one piece of food. On probe trials involving intermediate gray backgrounds, left side responses indicated optimism and right side responses indicated pessimism. Tests took place at the beginning, middle, and end of mulberry season and again nearing the end of the summer and early fall before hibernation. The bear showed the most optimistic responses during the phase involving increased opportunities for foraging on mulberry. A follow-up experiment confirmed that the bear preferred three food items over one food item, suggesting the quantity-based discrimination was in fact salient to this bear. This is the first evidence for conditional discrimination learning in a black bear, validating the task to assess changes in affect.

中文翻译：

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结出果实：在美国黑熊中试行一项新颖的判断偏见任务

判断偏差任务可以揭示动物情绪的变化，这是环境操作（例如提供丰富性）的函数。我们评估了美洲黑熊对桑树可用性季节性变化的影响。我们使用了一种新颖的判断偏差任务，其中触摸屏的背景颜色表示左侧或右侧定位的刺激是否正确。熊学习了条件规则，其中白色背景（选择左侧）的正确动作会导致三块食物，黑色背景的正确动作（选择右侧）会导致一块食物。在涉及中间灰色背景的探测试验中，左侧反应表明乐观，右侧反应表明悲观。测试发生在开始，中间，和桑椹季节的结束，再次接近夏末和冬眠前的初秋。熊在涉及增加在桑树上觅食的机会的阶段表现出最乐观的反应。一项后续实验证实，熊更喜欢三种食物而不是一种食物，这表明基于数量的歧视实际上对这只熊来说很突出。这是黑熊条件歧视学习的第一个证据，验证了评估情感变化的任务。这表明基于数量的歧视实际上对这只熊来说很突出。这是黑熊条件歧视学习的第一个证据，验证了评估情感变化的任务。这表明基于数量的歧视实际上对这只熊来说很突出。这是黑熊条件歧视学习的第一个证据，验证了评估情感变化的任务。