Constraints on perception : comparative and developmental aproaches

人类婴儿识别两个物体在闭塞物后面一起移动的统一性（物体统一性的感知）。这种感知表明，人类使用一些感知假设来识别外部物体。这个项目的目的是研究这种感知约束的演变。我们实验分析了非人类灵长类动物和鸟类的知觉完成过程。主要研究结果如下。簇尾卷尾猴被训练去匹配完整的对角杆、解剖杆和中心轮廓不规则的单一杆。然后测试受试者，他们将与中央部分被水平带遮挡的刺激相匹配。不管样本刺激是在封堵器后面水平移动还是静止不动，猴子绝大多数都将这些测试刺激与完整的直杆相匹配。因此，猴子们完成了一条直线轮廓中被遮挡的部分。当两根杆子被放置成直角支架（>）时，受试者也将它们与连接的杆子匹配。然而，当两根杆子平行放置时，受试者将它们与不相连的杆子匹配。因此，猴子根据这两个部分是否相连来识别被遮挡的两个片段的统一性。正在进行的研究表明，当杆状体的轮廓是锯齿形时，猴子倾向于完成锯齿形线条中看不见的部分。知觉完成的过程似乎遵循格式塔原则，即良好的形状和/或规律性，就像人类成年人一样。另一方面，鸽子在类似的情况下从来没有表现出知觉完成的证据。鸽子可能已经进化出一种与人类完全不同的视觉信息处理算法。我们现在用食物图片来测试鸽子。其他有不同饮食习惯的物种也在接受测试。猕猴的发育研究没有很好的结论。

Human infants recognize unity of two objects moving together behind an occluder (perception of object unity). Such perception shows that humans recognize external objects using some perceptual hypotheses. The purpose of this project was to study the evolution of such perceptual constraints. We experimentally analyzed the process of perceptual completion in nonhuman primates and birds. Major findings are as follows. Tufted capuchin monkeys were trained to match an intact diagonal rod, dissected rods, and unitary rods having irregular contour at their centers. Then the subjects were tested which they would match to the stimuli having their central portions occluded by a horizontal belt. Regardless of whether the sample stimuli moved horizontally behind the occluder or stayed stationary, the monkeys overwhelmingly matched these test stimuli to the intact, straight rod. Thus the monkeys completed the occluded portion in a straight contour. When two rods were placed to form a right-angle bracket (>), the subjects also matched them to the connected rod. When the two rods were placed parallel to each other, however, the subjects matched them to the disconnected rods. Thus the monkeys recognized the unity of the occluded two fragments based on whether the two portions were connective or not. Ongoing study shows that when the contour of the rods is zigzag, the monkeys tend to complete the invisible portions in zigzag lines. The process of perceptual completion seems to follow the Gestalt principles of good shape and/or regularity, like human adults. On the other hand, pigeons never showed evidence for perceptual completion in similar situations. Pigeons may have evolved with a visual information processing algorythm that is completely different from humans'. We are now testing pigeons using pictures of food. Other species having different food habits are also being tested. Developmental study of macaque monkeys reached no good conclusion.