Psychology

The goal of visual neuroscience is to understand how external light stimuli are received by the eye, processed by the brain, integrated with the internal state of the viewer and ultimately constructed into a perception, decision or action. As a heuristic, one can consider this whole process as a series of hierarchical stages. Visual neuroscience encompasses the whole process: from retina to perception. Some disciplines, like psychology and philosophy, make progress on understanding vision by digging from the perceptual end of the tunnel; other disciplines, like visual neurobiology, tackle the problem by digging at the other end of the tunnel, starting with theretinal signals.

Psychology tries to understand perception, by establishing accurate descriptions of perceptual states and what brings them about. This approach is complementary to visual neurobiology, which begins in the eye, and attempts to understand the computations performed on the retinal signal to achieve the perception. Many visual phenomena can be understood in terms of basic neurophysiological mechanisms in the early stages of visual information processing: trichromacy, coloropponency, local contrast, edge detection.  Other phenomena require more elaborate explanations for which we do not know, in concrete terms, the neurophysiological underpinnings. These phenomena usually require an understanding of the perceptual experience of the viewer: why are faces more recognizable when they are right-side up? Why do we automatically assume that light sources are coming from above? Why do painted shadows have to be relatively darker to be interpreted as shadows? Why is blue the predominant favorite color? Why does imagining yourself as residing inside the world depicted in a canvas deepen your experience of the artwork?

By considering more deeply our responses to visual stimuli, including artworks, we become aware of, and learn to describe and characterize, these phenomena. This will bring us closer to the goal of defining the neural computations that bring these perceptual states about.