BMI SEMINAR // Dejan Todorovic - Effects of context in perception and visual illusions

Identical objects and figures may look different in different contexts. This is a general phenomenon, manifested in many different domains of vision research, and it can provide important insights into various perceptual mechanisms. The talk will start with examples of salient contextual effects involving perception of transparency, gaze direction, 3D shape, and amodal completion. Most classical visual illusions can be characterized as contextual effects, but they also involve comparisons of reality and appearance, and can be defined in a simple conceptual framework, based on Aristotle’s definition of truth and falsehood. Demonstrations and experiments will be discussed which provide challenges to some higher-level accounts of illusory effects involving perception of lightness and size. Lastly, a number of examples of a class of strong illusions involving perception of orientation will be presented, as well as several simulations of a neurally based computational model of these effects.