Nothdurft Hans-Christoph, Pigarev Ivan N, Kastner Sabine
Visual Perception Laboratory (VPL) Göttingen, Germany.
J Integr Neurosci. 2009 Jun;8(2):137-74. doi: 10.1142/s0219635209002101.
In order to investigate the search performance and strategies of nonhuman primates, two macaque monkeys were trained to search for a target template among differently oriented distractors in both free-gaze and fixed-gaze viewing conditions (overt and covert search). In free-gaze search, reaction times (RT) and eye movements revealed the theoretically predicted characteristics of exhaustive and self-terminating serial search, with certain exceptions that are also observed in humans. RT was linearly related to the number of fixations but not necessarily to the number of items on display. Animals scanned the scenes in a nonrandom manner spending notably more time on targets and items inspected last (just before reaction). The characteristics of free-gaze search were then compared with search performance under fixed gaze (covert search) and with the performance of four human subjects tested in similar experiments. By and large the performance characteristics of both groups were similar; monkeys were slightly faster, and humans more accurate. Both species produced shorter RT in fixed-gaze than in free-gaze search. But while RT slopes of the human subjects still showed the theoretically predicted difference between hits and rejections, slopes of the two monkeys appeared to collapse. Despite considerable priming and short-term learning when similar tests were continuously repeated, no substantial long-term training effects were seen when test conditions and set sizes were frequently varied. Altogether, the data reveal many similarities between human and monkey search behavior but indicate that search is not necessarily restricted to exclusively serial processes.
为了研究非人类灵长类动物的搜索性能和策略，训练了两只猕猴在自由注视和固定注视观察条件下（公开和隐蔽搜索），在不同方向的干扰物中搜索目标模板。在自由注视搜索中，反应时间（RT）和眼动揭示了理论上预测的穷举式和自终止序列搜索的特征，但也有一些在人类中也观察到的例外情况。反应时间与注视次数呈线性相关，但不一定与显示的项目数量相关。动物以非随机方式扫描场景，在目标和最后检查的项目（就在反应前）上花费的时间明显更多。然后将自由注视搜索的特征与固定注视（隐蔽搜索）下的搜索性能以及在类似实验中测试的四名人类受试者的性能进行比较。总体而言，两组的性能特征相似；猴子稍快，人类更准确。两种物种在固定注视搜索中的反应时间都比自由注视搜索中的短。但是，虽然人类受试者的反应时间斜率仍然显示出命中和拒绝之间理论上预测的差异，但两只猴子的斜率似乎没有区别。尽管在不断重复类似测试时有相当大的启动效应和短期学习，但当测试条件和集合大小频繁变化时，没有看到实质性的长期训练效果。总之，数据揭示了人类和猴子搜索行为之间的许多相似之处，但表明搜索不一定仅限于完全串行的过程。
