Illusion susceptibility in domestic dogs

Abstract

Domestic dogs play many vital roles in human lives; however, relatively little is known about how they perceive the world visually. Given dogs’ recent popularity as a subject in cognitive and behavioural studies, it is important to understand how they visually interpret the world around them. One way to evaluate perception is to assess illusion susceptibility; specifically, how visual information is processed, interpreted and modified post‐retinally. While illusion susceptibility has been used across a variety of species to comparatively assess the similarities and differences in visual processing and perception, this relatively novel methodological approach has only recently been adapted to evaluate perception in domestic dogs. Here, we present a comprehensive overview of the findings from studies that have evaluated domestic dogs’ illusion susceptibility, highlighting the relevance of these results for those studying illusion susceptibility in animals as well as canine behaviour and cognition. More specifically, the ultimate goal of this review is to answer the questions: (a) Are dogs susceptible to visual illusions? (b) If so, are they susceptible to illusions in a way that parallels humans and/or other animals? (c) Are findings, within dogs, consistent and if not, how might these be interpreted and explained?

Using illusions to interview animals about how they perceive the world

“…Until today, our answer was that this is a new section and that we cannot provide a role model, because there was none. As of today, this has changed: in this issue of Ethology , Sarah‐Elizabeth Byosiere, Philippe Chouinard, Tiffani Howell and Pauleen Bennett explore how domestic dogs perceive the visual world in comparison with humans (Byosiere, Chouinard, Howell, & Bennett, 2020).…”

“…In the lecture, I had assumed that pipefish would fall for the illusion just as humans do. But after having read Byosiere et al's (2020) article I now wonder if they really do? Is their perceptual world comparable to ours?…”

“…In their Species‐in‐the‐Spotlight article Byosiere et al (2020) use a set of visual illusions known to trick humans and review if domestic dogs can be fooled by such illusions as well. This review is an eye‐opener in highlighting a few similarities, but most of all the substantial differences in the visual perceptual worlds of humans and “man's best friend.” Given how intimately dogs and humans interact and communicate I was stunned to learn how different they and us may perceive and process information from the visual world.…”

Methodological Challenges in the Assessment of Dogs' (Canis lupus familiaris) Susceptibility of the Ebbinghaus-Titchener Illusion Using the Spontaneous Choice Task

“…Various theoretical explanations exist to interpret, typically, human-like illusion susceptibility. Susceptibility to the Ebbinghaus-Titchener illusion is often explained by the size contrast theory (Coren & Enns, 1993) while susceptibility to the Delboeuf illusion is often explained by the contour interaction (Jaeger, 1978;Jaeger & Lorden, 1980) and assimilation theories (Pressey, 1971; for a review of the theories underlying canine illusion susceptibility see Byosiere et al, 2020). In humans, the Ebbinghaus-Titchener has been proposed to be more robust, having a stronger illusory effect than the Delboeuf illusion (Nakamura et al, 2014).…”

“…However, illusion susceptibility also invokes a discussion of visual processing precedence, specifically the perceptual processing mode of the species. Species that demonstrate human-like susceptibility are generally believed to process visual stimuli at a global level (Byosiere et al, 2020;Kelley & Kelley, 2014;Nakamura et al, 2008Nakamura et al, , 2014, meaning they integrate and perceive stimuli as a whole composition rather than as individual components (Navon, 1977). Conversely, those that demonstrate null or reversed susceptibility are believed to process these stimuli at a local level (Byosiere et al, 2020;Kelley & Kelley, 2014;Nakamura et al, 2008Nakamura et al, , 2014, prioritizing the individual components rather than the whole composition (de Fockert et al, 2007).…”