Characteristics of Spatial Memory

我们所有人都曾在这样或那样的时候，煞费苦心地把一件珍贵的东西放在某个特别的地方，以便把它藏得很好。我们也确信我们永远不会忘记这个地方。然而，当我们要找回这个东西的时候，我们却记不起把它藏在哪里了。美国西部的一些鸟类也有类似的行为，但有一个重要的区别。他们似乎没有忘记他们隐藏的宝藏的位置。利用空间记忆的一个最引人注目的例子是种子贮藏鸟，它们可以记住数千个不同地点的位置长达数月之久。这些物种的空间记忆能力很强，持续时间很长。在这一系列的实验中，巴尔达博士和他的同事们将使用精心管理的实验室程序来研究克拉克的胡桃鸦、矮松鸦和矮松鸦的记忆系统的本质，其中许多变量都是可以操纵和控制的。在自然界中，这些鸟每年秋天都会花费数百个小时从本地针叶树上收获松树种子，把这些种子带到很远的地方，然后把种子埋在地下的贮藏库中。这些缓存的种子没有暴露，无法检测到。然而，这些鸟在几个月后回到这些贮藏地点，并以几乎无误的准确性找到了它们的贮藏地。需要解决的问题包括：一只鸟能记住多少个贮藏地点？这些遗址能被记住多久？幼鸟的这种行为是如何发展的？鸟类记忆的信息量是否存在物种差异？本研究的结果将有助于我们从进化和行为两个层面理解空间记忆，并从广阔的生物学和心理学角度理解动物的认知。

All of us have, at one time or another, taken special pains to place a prized object in some special location where it would be well hidden. We were also sure we would never forget this location. However, when it was time to retrieve the object, we could not remember where we had hidden it. Some species of birds in the western U.S. perform a similar behavior, but with one important difference. They appear not to forget the location of their hidden treasure. One of the most dramatic examples of the use of spatial memory is provided by seed-caching birds that remember the location of thousands of distinct locations for many months. Spatial memory in these species is robust and of long duration. In this series of experiments, Dr. Balda and his colleagues will study the nature of this memory system in Clark's nutcracker, pinyon jays, and scrub jays using carefully managed laboratory procedures in which many variables can be manipulated and controlled. In nature, these birds spend hundreds of hours each autumn harvesting pine seeds from native conifer trees, carrying these seeds off some distance, and then burying the seeds in underground caches. These cached seeds are not exposed and cannot be detected. Yet, these birds return to these cache sites months later and recover their caches with almost errorless accuracy. Questions to be addressed include: How many cache sites can a bird remember? How long can these sites be remembered? How does this behavior develop in young birds? Are there species differences in how much information birds can remember? The results of this research will help us to understand spatial memory at both the evolutionary and behavioral levels and to develop an understanding of animal cognition in a broad biological and psychological perspective.