Abstract
Does knowing what an object is change its visual representation? Recent behavioral and neuroimaging work has begun to provide important insights into the effects of conceptual categories on visual processing (Puri & Wojciulik, 2008; Lupyan & Spivey, 2008; Esterman & Yantis, 2008 http://journalofvision.org/8/6/555/) showing that performance on tasks traditionally thought to be purely visual (e.g., visual search and physical identity judgments) can be affected by conceptual factors. For example, Lupyan (Cognition; 2008) reported the existence of conceptual grouping: performance in a visual search task was facilitated through grouping of items from the same conceptual category. Controlling for visual similarity, searching for a target among conceptually homogeneous distractors was faster than among conceptually heterogeneous distractors. Rather than resulting from long-term perceptual warping (e.g.,. Goldstone, 1998), the conceptual grouping effect appeared to emerge on-line.
Here, we report a series of experiments that (1) provide the strongest evidence yet for an on-line effect of categories on visual processing and (2) outline a robust methodology for studying such effects.
Participants were required to respond “same” to pairs of identical pictures and “different” to pairs of different pictures. On “different” trials, the stimuli could either be in the same conceptual category (e.g., two different chairs: C+ trials) or in different conceptual categories (e.g., a chair and a lamp: C− trials). Importantly, on some trials the two pictures appeared simultaneously while on others the second picture appeared after a delay. The two pictures were always visible when the response was made.
When visual similarity between/within categories was controlled, C+ responding was slower than C− responding only at SOAs[[gt]]0. Thus, category membership automatically affects visual judgments but the effect takes time to emerge.
Subsequent experiments showed that such effects are modulated by item typicality. Category information affects RTs for typical items but not atypical items.