Blindsight is the ability to respond to visual information without consciously seeing it. Psychologists study blindsight to learn more about how the brain processes visual information. Conscious vision depends on the primary visual cortex; however, people have demonstrated blindsight when this area of their brain is damaged. This suggests that another area (or areas) of the brain controls unconscious visual perception. Patients who have no conscious awareness of seeing objects have detected them in their path and moved around them. Such patients have also responded to color, emotion expressed by human faces, and motion (for example, supplying correct answers when asked to guess where an object is moving). Blindsight suggests that sometimes acting on information does not require conscious awareness of that information.