Abstract
Does a gray banana look yellow? Does a heart look redder than a square? A line of research stretching back nearly a century suggests that knowing an object's canonical color can alter its visual appearance. Are such effects truly perceptual, or might they instead reflect biased responses without altering online color perception? Here, we replicate classical and contemporary "memory-color effects", but then extend them to include conditions with counterintuitive hypotheses that would be difficult for subjects to grasp; across multiple case studies, we find that such conditions eliminate or even reverse memory-color effects in ways unaccounted-for by these theories. We first replicated the classic finding that hearts are judged as redder than squares, as measured by matching a color-adjustable background to a central stimulus. But when we varied the shape of the background itself (to be either square or heart-shaped), subjects who estimated a square's color by adjusting a heart-shaped background adjusted the background to be redder than when adjusting a square-shaped background — whereas a memory-color theory would predict the opposite pattern. Next, we successfully replicated the more recent finding that gray disks and blueish bananas are judged as more purely gray than are gray bananas (which purportedly appear yellow); however, we also found that a blueish disk is judged to be more gray than a blueish banana, exactly opposite the prediction of memory-color theories. Moreover, when asked to identify the "odd color out" from an array of three objects (e.g., gray disk, gray banana, and blueish banana) subjects easily identified the blueish banana as the odd color out, even though memory-color theories predict that subjects should pick the gray banana. We suggest that memory color effects may not be truly perceptual, and we discuss the utility of this general approach for distinguishing perception from cognition.
Meeting abstract presented at VSS 2018