Miletto Petrazzini Maria Elena, Bisazza Angelo, Agrillo Christian
Department of General Psychology, University of Padova, Via Venezia 8, 35131, Padua, Italy.
Anim Cogn. 2017 May;20(3):427-434. doi: 10.1007/s10071-016-1066-2. Epub 2016 Dec 20.
In the last decade, visual illusions have been repeatedly used as a tool to compare visual perception among species. Several studies have investigated whether non-human primates perceive visual illusions in a human-like fashion, but little attention has been paid to other mammals, and sensitivity to visual illusions has been never investigated in the dog. Here, we studied whether domestic dogs perceive the Delboeuf illusion. In human and non-human primates, this illusion creates a misperception of item size as a function of its surrounding context. To examine this effect in dogs, we adapted the spontaneous preference paradigm recently used with chimpanzees. Subjects were presented with two plates containing food. In control trials, two different amounts of food were presented in two identical plates. In this circumstance, dogs were expected to select the larger amount. In test trials, equal food portion sizes were presented in two plates differing in size: if dogs perceived the illusion as primates do, they were expected to select the amount of food presented in the smaller plate. Dogs significantly discriminated the two alternatives in control trials, whereas their performance did not differ from chance in test trials with the illusory pattern. The fact that dogs do not seem to be susceptible to the Delboeuf illusion suggests a potential discontinuity in the perceptual biases affecting size judgments between primates and dogs.
在过去十年中，视觉错觉被反复用作比较不同物种视觉感知的工具。多项研究调查了非人类灵长类动物是否以类似人类的方式感知视觉错觉，但对其他哺乳动物的关注甚少，而且从未对狗对视觉错觉的敏感性进行过研究。在此，我们研究了家犬是否能感知德勃夫错觉。在人类和非人类灵长类动物中，这种错觉会根据物体周围的背景对物体大小产生错误感知。为了在狗身上检验这种效应，我们采用了最近用于黑猩猩的自发偏好范式。给实验对象呈现两个装有食物的盘子。在对照试验中，在两个相同的盘子里呈现不同数量的食物。在这种情况下，预计狗会选择数量较多的食物。在测试试验中，在两个大小不同的盘子里呈现等量的食物：如果狗像灵长类动物一样感知到错觉，预计它们会选择较小盘子里的食物量。狗在对照试验中能够显著区分两种选择，而在有错觉图案的测试试验中，它们的表现与随机水平无异。狗似乎不易受德勃夫错觉影响这一事实表明，在影响灵长类动物和狗大小判断的感知偏差方面可能存在不连续性。
