What is Visual Capture?

Visual capture is a phenomenon in human perception where people tend to rely most heavily on visual images and the things they see dominate their understanding of a scene. If something feels inconsistent or does not make sense, the brain may unconsciously smooth it out, relying on visual capture to decide how to interpret the information in a way that will feel logical. Awareness of this quirk of human perception lies behind a number of stage tricks and pranks, and can also explain human behavior in some environments.

One of the most well known examples of visual capture is ventriloquism. When an actor and a dummy sit together on stage and the actor manipulates the dummy's mouth while speaking, the audience will perceive the speech as coming from the dummy. Some practice is necessary to perform this trick well, as the ventriloquist wants to move his mouth as little as possible, forcing people to transfer perception to the dummy to explain where the voice is coming from.

Other stage tricks use this tactic, either employing visual distractions to hide activities on stage, or relying on visual capture to directly trick people. In psychology, this concept also has important applications to understanding how people perceive things. At movie theaters, for example, if a researcher asks attendees where the sound is coming from, they will point at the screen, even though the speakers may be in the back of the room or along the walls. They see the moving lips, explosions, and other events on screen, and associate the sound with the picture.

The dominance of vision in human perception can also have interesting implications for some forms of therapy. Some people experience a condition called phantom limb syndrome, where they experience sensory input from an amputated limb. One very effective treatment is mirroring, where the patient works with a mirror and the intact limb. As the patient moves the intact limb in the mirror, visual capture takes over, making her feel like she is moving the amputated limb, even though it's not actually there. Using this technique, therapists can help patients manage phantom limb syndrome.

Vision itself is a complex source of sensory input and a number of things can interfere with visual perception. The brain needs to be able to process huge amounts of incoming visual material very rapidly, and it is adept at sifting through that information to find the most meaningful data. For example, people can usually identify human faces in a scene very rapidly, a distinct evolutionary advantage, since humans need to be able to recognize members of their own species quickly.