Abstract
Familiar size is an important cue to size and distance perception. For example, the perceived size of a car stays constant regardless of how far away it is. Relative size is also an important cue, as demonstrated by the size contrast effect in the Ebbinghaus illusion. But what happens when familiar and relative sizes conflict? Will our expectation of familiar sizes in the real world affect how we perceive size? Moreover, given that familiar size is an important organizational principle in the ventral visual stream for inanimate but not for animate objects (Konkle & Caramazza, 2013, J Neurosci), does the influence of familiar size depend on animacy? Participants judged the size of a central stimulus in the Ebbinghaus illusion, where the surrounding stimuli were physically larger or smaller than the central stimulus. The central stimulus was an animate or an inanimate stimulus of medium familiar size (Dalmatian dog or armchair, respectively) surrounded by other stimuli of smaller or larger familiar size that were animate (cats or horses) or inanimate (shoes or cars). For both the animate (dog) and inanimate (armchair) central images, perceived size was more affected by size congruency for inanimate than animate surrounds. Specifically, the size contrast illusion was strongest for incongruent size relationships with inanimate objects (e.g., a dog surrounded by small cars was perceived as considerably larger than a dog surrounded by large shoes) and weakest for congruent size relationships with inanimate objects (e.g., a dog surrounded by large cars was perceived as a similar size to a dog surrounded by small shoes). The results show that inanimate objects are more influential benchmarks for size perception than animate objects. Moreover, they show that differences between inanimate and animate stimuli in the organization of the ventral stream are reflected in behavioral size perception.
Meeting abstract presented at VSS 2017