Department of Psychology, Tufts University, 490 Boston Avenue, Medford, MA, 02155, USA.
Department of Psychology, University of Manitoba, Winnipeg, Manitoba, Canada.
Psychon Bull Rev. 2018 Dec;25(6):2274-2280. doi: 10.3758/s13423-018-1439-4.
Clark's nutcrackers exhibit remarkable cache recovery behavior, remembering thousands of seed locations over the winter. No direct laboratory test of their visual memory capacity, however, has yet been performed. Here, two nutcrackers were tested in an operant procedure used to measure different species' visual memory capacities. The nutcrackers were incrementally tested with an ever-expanding pool of pictorial stimuli in a two-alternative discrimination task. Each picture was randomly assigned to either a right or a left choice response, forcing the nutcrackers to memorize each picture-response association. The nutcrackers' visual memorization capacity was estimated at a little over 500 pictures, and the testing suggested effects of primacy, recency, and memory decay over time. The size of this long-term visual memory was less than the approximately 800-picture capacity established for pigeons. These results support the hypothesis that nutcrackers' spatial memory is a specialized adaptation tied to their natural history of food-caching and recovery, and not to a larger long-term, general memory capacity. Furthermore, despite millennia of separate and divergent evolution, the mechanisms of visual information retention seem to reflect common memory systems of differing capacities across the different species tested in this design.
栗啄木鸟表现出显著的贮藏物找回行为，能在整个冬季记住数千个种子的位置。然而，尚未对其视觉记忆能力进行直接的实验室测试。在这里，两只栗啄木鸟在用于测量不同物种视觉记忆能力的操作性程序中接受了测试。栗啄木鸟在一个二选一的辨别任务中，通过一个不断扩大的图片刺激库进行增量测试。每张图片都被随机分配到右或左选择反应，迫使栗啄木鸟记住每张图片-反应的关联。栗啄木鸟的视觉记忆能力估计略高于 500 张图片，测试表明存在优先级、最近记忆和随时间记忆衰减的影响。这种长期视觉记忆的大小小于为鸽子确定的约 800 张图片的容量。这些结果支持这样的假设，即栗啄木鸟的空间记忆是一种专门的适应，与它们的觅食和回收的自然历史有关，而不是与更大的长期、一般记忆能力有关。此外，尽管经历了数千年的独立和不同的进化，视觉信息保留的机制似乎反映了不同物种在这种设计中测试的不同容量的共同记忆系统。
