On the Goal of Visual Perception

Regardless of whether one adopts an indirect or a direct theory of visual perception, it is assumed that the properties of the world are recovered. Here we argue that the key to understanding visual perception is to reject this assumption.  By shifting the goal of vision away from recovering properties to the more instrumental goal of guiding useful behavior, a naturalized framework emerges that offers greater explanatory power in both the philosophy and science of perception.

Wojtach, W.T., & Purves, D. (under review)

 

Significance of “The Dress”

While explaining the perception of color has always been daunting, the difficulty of this challenge has increased as a result of recent evidence that the same spectral stimulus can elicit radically different perceptions in different people.  Although a range of explanations for the apparent color of “the dress” have been suggested, a satisfactory answer has not been offered—and, therefore, no consensus has emerged. Here we offer a different explanation, pointing out that whatever the answer turns out to be, the much-debated photo undermines some entrenched ideas about perception.

Purves, D. & Wojtach, W.T. (in revision)

 

Perceived Time and Distance

It is often assumed that we and other animals measure time and distance in much the same way clocks and rulers do.  Here we show that the perception of time over intervals of milliseconds to seconds is routinely foreshortened when objects are in motion.  By the same token, the perceived distance something travels is routinely increased.  Just as the luminance of retinal stimuli conflates reflectance and illumination, motion stimuli conflate time and distance.  The outcome in both cases is a disconnection between perception and the physical world.  These results suggest that current explanations based on: (1) visual processing in terms of “spatiotemporal energy;” (2) image features;  and (3) statistical inferences about the state of the world are incorrect, and a different theoretical standpoint is needed to explain the way we experience time and distance.

Purves, D. & Wojtach, W.T. (in progress)