Overduin-de Vries A M, Spruijt B M, Sterck E H M
Biomedical Primate Research Centre, Postbus 3306, 2280 GH, Rijswijk, The Netherlands,
Anim Cogn. 2014 Jan;17(1):77-84. doi: 10.1007/s10071-013-0639-6. Epub 2013 May 12.
Visual perspective taking (VPT), an understanding of what others can see, is a prerequisite for theory of mind (ToM). While VPT in apes is proven, its presence in monkeys is much-debated. Several different paradigms have been developed to test its existence, but all face interpretational problems since results can be explained by simpler cognitive mechanisms than VPT. Therefore, we adjusted one method where two individuals compete for access to food, visible or invisible for the dominant competitor, to preclude cognitively simpler mechanisms. The subordinate long-tailed macaques tested, selected significantly more often the food item invisible than the item visible to the dominant. In most trials, subjects retrieved only one food item and preferred the invisible food item. Surprisingly, they occasionally adopted an alternative strategy to obtain both food items, by first choosing the visible, most at risk food item. Faster animals adopted this strategy proportionally more often than slower ones. Contrary to previous research, our results cannot be explained by simpler cognitive mechanisms, since behavioural reading was prevented by a one-way mirror between the competitor and the food, and accessibility was equal to both food items. This is the first unequivocal evidence of VPT in a monkey species, suggesting that this precursor to ToM is an evolutionarily conserved capacity present in monkeys, apes and humans.
视觉观点采择（VPT），即理解他人所能看到的事物，是心理理论（ToM）的一个先决条件。虽然猿类的视觉观点采择已得到证实，但其在猴子中的存在仍存在诸多争议。已经开发了几种不同的范式来测试其是否存在，但所有这些范式都面临解释问题，因为结果可以用比视觉观点采择更简单的认知机制来解释。因此，我们调整了一种方法，即让两个个体竞争获取食物，对于占主导地位的竞争者来说，食物是可见或不可见的，以排除认知上更简单的机制。接受测试的从属长尾猕猴明显更频繁地选择对占主导地位者不可见的食物项目，而不是可见的食物项目。在大多数试验中，受试者只获取一个食物项目，并且更喜欢不可见的食物项目。令人惊讶的是，它们偶尔会采用另一种策略来获取两个食物项目，即先选择可见的、风险最大的食物项目。速度较快的动物比速度较慢的动物更频繁地采用这种策略。与先前的研究相反，我们的结果不能用更简单的认知机制来解释，因为竞争者与食物之间的单向镜阻止了行为解读，并且获取两种食物项目的机会是均等的。这是猴子物种中视觉观点采择的首个明确证据，表明心理理论的这个前身是猴子、猿类和人类中存在的一种进化上保守的能力。
