日本研究人员3月26日说,老鼠等啮齿动物经过训练,也能学会使用工具并理解工具的用途。科学家此前普遍认为,只有灵长类动物和一些鸟类能使用工具。
日本理化研究所研究人员选取6只成年八齿鼠作为实验对象,训练它们用微型T型耙取食物。八齿鼠原产智利,是一种体型较小的老鼠。整个实验为期60天。这些八齿鼠在实验最后阶段全部能够熟练使用T型耙,它们能抓住T型耙,顺利将前方的食物耙到自己身边。
研究人员认为,这项研究显示,动物能否使用工具,最重要的是“社会-生态学”因素。主持这项研究的冈屋和夫(音译)说:“传统观点认为,使用工具是一种高级能力。但属于啮齿动物纲的动物如果经过相应训练,也可以做到这一点。”冈屋说,这项研究意味着种类相当广泛的动物存在学会使用工具的可能。
研究人员还发现,八齿鼠还能识别有用的工具。在一项测试中,他们在这些八齿鼠面前放上两种耙子,一种耙子可以实际使用,八齿鼠也较为熟悉;另一种耙子没有耙钉,或者耙钉凸起,没有实际功能。
结果发现,在大多数情况下,八齿鼠会毫不犹豫地选择具有实际功能的耙子,而且它们在作出正确选择时,不会受工具颜色或大小的干扰。
研究人员说,成功使用系统方法训练啮齿动物操作工具、理解工具用途,这在世界上尚属首次。
这项研究成果发表在美国《公共科学图书馆·综合》(PLoS ONE)上。(来源:新华网)
生物谷推荐原始出处:
(PLoS ONE),doi:10.1371/journal.pone.0001860,Kazuo Okanoya,Atsushi Iriki
Tool-Use Training in a Species of Rodent: The Emergence of an Optimal Motor Strategy and Functional Understanding
Kazuo Okanoya1, Naoko Tokimoto1,2, Noriko Kumazawa2, Sayaka Hihara2, Atsushi Iriki2*
1 Laboratory for Biolinguistics, Brain Science Institute, RIKEN, Saitama, Japan2 Laboratory for Symbolic Cognitive Development, Brain Science Institute, RIKEN, Saitama, Japan
Abstract
Background
Tool use is defined as the manipulation of an inanimate object to change the position or form of a separate object. The expansion of cognitive niches and tool-use capabilities probably stimulated each other in hominid evolution. To understand the causes of cognitive expansion in humans, we need to know the behavioral and neural basis of tool use. Although a wide range of animals exhibit tool use in nature, most studies have focused on primates and birds on behavioral or psychological levels and did not directly address questions of which neural modifications contributed to the emergence of tool use. To investigate such questions, an animal model suitable for cellular and molecular manipulations is needed.
Methodology/Principal Findings
We demonstrated for the first time that rodents can be trained to use tools. Through a step-by-step training procedure, we trained degus (Octodon degus) to use a rake-like tool with their forelimbs to retrieve otherwise out-of-reach rewards. Eventually, they mastered effective use of the tool, moving it in an elegant trajectory. After the degus were well trained, probe tests that examined whether they showed functional understanding of the tool were performed. Degus did not hesitate to use tools of different size, colors, and shapes, but were reluctant to use the tool with a raised nonfunctional blade. Thus, degus understood the functional and physical properties of the tool after extensive training.
Conclusions/Significance
Our findings suggest that tool use is not a specific faculty resulting from higher intelligence, but is a specific combination of more general cognitive faculties. Studying the brains and behaviors of trained rodents can provide insights into how higher cognitive functions might be broken down into more general faculties, and also what cellular and molecular mechanisms are involved in the emergence of such cognitive functions.