Determination of tridimensionality perception in Canis lupus familiaris through the use of optical illusions

While numerous studies have demonstrated the ability of various animals to perceive three-dimensionality, few have directly investigated whether this capability is possessed by dogs, particularly if it could arise from the use of monocular cues. This thesis is part of a broader study aimed at exploring this possibility, as its results can enhance our understanding of animal visual perception, especially since dogs are often used as model organisms. Additionally, these results can be used in comparative studies with other species to clarify the evolution of visual perception. For this purpose, an experimental apparatus was designed to present dogs with what should be perceived as an unexpected scenario. A ball was shown crossing a plastic board that could be manipulated into two distinct conditions: a "real hole" condition, where a hole was cut into the board, and an "illusory hole" condition, where the same hole was covered with a panel simulating the three-dimensional hole on a two-dimensional surface using shading and linear perspective as monocular cues. According to the violation of expectation paradigm, dogs spent more time observing the scenario where the ball crossed the illusory hole compared to when it fell into the real hole. This result suggests that a surprise reaction was triggered in dogs that, indicating that they were sensitive to the monocular cues for perceiving tridimensionality.