Effects of natural categories on pictorial short term memory in pigeons.

四只鸽子接受了相同/不同任务的训练，并连续呈现了成对的幻灯片图片。在同样的实验中，在消光效果生效时，放映一张与前一次实验相同的幻灯片10秒钟。在不同的试验中，与前一次试验不同的幻灯片上的键盘敲击以平均6秒的不规则间隔加强。幻灯片上有各种各样的120张图片，如山脉，建筑物，动物和杂项物体。在实验1中，训练结束后，间隔时间延长。尽管表现随着停留时间的延长而下降，但即使在最长的停留时间为50秒时，鸽子也保持了相对较好的表现，比物理刺激（如颜色或线条方向）的时间更长。实验2，在相同的实验中，旋转载玻片，对被试进行正常方向、左右翻转、上下翻转、左右和上下翻转的图片测试。实验对象先看90张新奇的图片，然后再看90张熟悉的图片。受试者在使用新图片时表现得不太准确，从上到下的倒换比从左到右倒换对表现的负面影响更大。被试对熟悉图片保持准确的表现，熟悉图片的反转对表现没有影响。因此，相对较长的记忆对鸽子的幻灯片识别有效，并且熟悉的图片旋转不会改变幻灯片识别所需的信息。受试者可能将幻灯片的信息作为一个整体，而不是图片的一小部分来进行幻灯片识别。

Four pigeons were trained in a same/different task with successively presented pairs of slide pictures. On same trials, a slide identical to that of the previous trial was presented for 10 sec while extinction was in effect. On different trials, keypeckings to a slide different from that of the previous trial were reinforced at irregular intervals averaging 6 sec. The slides were a wide variety of 120 pictures such as mountains, builidings, animals, and miscellaneous objects. In Experiment 1, intertrial interval was lengthened after completion of the training. Although per-formance decreased as a function of retention interval, the pigeons retained relatively good performance even at the longest in terval of 50 sec, longer than with physical stimuli such as color or line orientation. In Experiment 2, the slides were rotated on same trials, and the subjects were tested with normally oriented pictures, left-right reversals, top-bottom reversals, and left-right and top-bottom reversals. The subjects were tested with 90 novel pictures and then with 90 familiar pictures. The subjects performed less accurately with reversed novel pictures, and top-bottom reversal more adversely affected performance than left-right reversal. The subjects maintained accurate performance with familiar ones and reversals of familiar picture had no effect on performance. Therefore, relatively long memory was in effect for pigeons' slide identification, and rotation of familiar pictures did not change the information necessary for slide identification. The subjects may have used the information of a slide as a whole, rather than small parts of picture, for slide identification.