DiPietro Norma T, Wasserman Edward A, Young Michael E
Department of Psychology, University of Iowa, Iowa City 52242-1407, USA.
Perception. 2002;31(11):1299-312. doi: 10.1068/p3441.
Casual observation suggests that pigeons and other animals can recognize occluded objects; yet laboratory research has thus far failed to show that pigeons can do so. In a series of experiments, we investigated pigeons' ability to 'name' shaded, textured stimuli by associating each with a different response. After first learning to recognize four unoccluded objects, pigeons had to recognize the objects when they were partially occluded by another surface or when they were placed on top of another surface; in each case, recognition was weak. Following training with the unoccluded stimuli and with the stimuli placed on top of the occluder, pigeons' recognition of occluded objects dramatically improved. Pigeons' improved recognition of occluded objects was not limited to the trained objects but transferred to novel objects as well. Evidently, the recognition of occluded objects requires pigeons to learn to discriminate the object from the occluder; once this discrimination is mastered, occluded objects can be better recognized.
日常观察表明，鸽子和其他动物能够识别被遮挡的物体；然而，迄今为止的实验室研究尚未表明鸽子有此能力。在一系列实验中，我们通过将每个有阴影、有纹理的刺激与不同反应相关联，来研究鸽子“命名”这些刺激的能力。在首先学会识别四个未被遮挡的物体之后，鸽子必须在物体被另一个表面部分遮挡或放置在另一个表面之上时识别这些物体；在每种情况下，识别能力都很弱。在用未被遮挡的刺激以及放置在遮挡物之上的刺激进行训练之后，鸽子对被遮挡物体的识别能力显著提高。鸽子对被遮挡物体识别能力的提高不仅限于经过训练的物体，还能转移到新的物体上。显然，识别被遮挡的物体需要鸽子学会将物体与遮挡物区分开来；一旦掌握了这种区分，就能更好地识别被遮挡的物体。
