Keep Benjamin, Zulch Helen E, Wilkinson Anna
School of Life Sciences, Joseph Banks Laboratories, Green Lane, University of Lincoln, Lincoln, LN6 7DL, UK.
Dogs Trust, London, UK.
Learn Behav. 2018 Dec;46(4):501-512. doi: 10.3758/s13420-018-0344-z.
Visual illusions are objects that are made up of elements that are arranged in such a way as to result in erroneous perception of the objects' physical properties. Visual illusions are used to study visual perception in humans and nonhuman animals, since they provide insight into the psychological and cognitive processes underlying the perceptual system. In a set of three experiments, we examined whether dogs were able to learn a relational discrimination and to perceive the Müller-Lyer illusion. In Experiment 1, dogs were trained to discriminate line lengths using a two-alternative forced choice procedure on a touchscreen. Upon learning the discrimination, dogs' generalization to novel exemplars and the threshold of their abilities were tested. In the second experiment, dogs were presented with the Müller-Lyer illusion as test trials, alongside additional test trials that controlled for overall stimulus size. Dogs appeared to perceive the illusion; however, control trials revealed that they were using global size to solve the task. Experiment 3 presented modified stimuli that have been known to enhance perception of the illusion in other species. However, the dogs' performance remained the same. These findings reveal evidence of relational learning in dogs. However, their failure to perceive the illusion emphasizes the importance of using a full array of control trials when examining these paradigms, and it suggests that visual acuity may play a crucial role in this perceptual phenomenon.
视觉错觉是由一些元素组成的物体，这些元素的排列方式会导致对物体物理属性的错误感知。视觉错觉被用于研究人类和非人类动物的视觉感知，因为它们能深入了解感知系统背后的心理和认知过程。在一组三个实验中，我们研究了狗是否能够学会关系辨别并感知缪勒-莱尔错觉。在实验1中，使用触摸屏上的二选一强制选择程序训练狗辨别线的长度。在学会辨别后，测试狗对新范例的泛化能力及其能力阈值。在第二个实验中，向狗呈现缪勒-莱尔错觉作为测试试验，同时还有控制总体刺激大小的额外测试试验。狗似乎能感知到这种错觉；然而，对照试验表明它们是利用整体大小来完成任务的。实验3呈现了已知能增强其他物种错觉感知的修改后的刺激。然而，狗的表现仍然相同。这些发现揭示了狗存在关系学习的证据。然而，它们未能感知到错觉强调了在研究这些范式时使用一系列完整对照试验的重要性，并且表明视力可能在这种感知现象中起关键作用。
