Biological motion

Biological movement is a term used in experimental psychology and psychophysics. Also indicated is thus a category of visual (or audible ) stimuli, which are typically used in experiments to explore the foundations of perception, to make a diagnosis, or to also demonstrate exceptional performance of perception. "Biological motion " can be defined as the apparent, active transport of living organisms, especially the visual representation of human movement. "Biological motion " is also often used as shorthand for the so-called point-light biological motion. In such motion patterns are only a few moving dots on a homogeneous background is visible (typically 10-20). These points are usually placed (Demo :) at the joints and distal ends of the body extremities.

Prehistory

The term "biological motion " was introduced in 1973 by the Swedish psychologist Gunnar Johansson experimental in the context of so called light point runners. Johansson worked up to that point in the development of gestalt laws for the perception of small groups of white dots on black background. He discovered regularities for expansion, translation, rotation and swinging movements. In order to test his findings on natural movements he developed video process to represent movement in the human light points. Johansson mounted lamps persons to the positions of the joints and then filmed while they were moving in the dark. He had developed a stimulus, which was largely independent of image and shape information. His astonishing finding was that human biological motion despite greatly reduced hints much better perceive as was expected based on the Gestalt laws. This finding was reinforced in the late 1970s and 1980s on. For example, gender differences, moods or even the identity of a person by means of the light spot rotor can be detected.

Perception mechanism

Although the term suggests "biological motion " that it is a kind of visual motion perception, suggests Johansson embedding at the level of Gestalt laws already that no typical processing mechanisms of visual motion is based. It was recognized early that Läsionspatienten who have difficulty with the motion detection, can still see very good biological movement on the basis of the point of light runner. While patients who have difficulty recognizing objects also have difficulty detecting biological motion by means of the light spot runner. These findings were confirmed in healthy individuals.

Neural mechanism

Electrophysiological studies in macaques showed that certain cells in the secondary auditory cortex, the superior temporal sulcus react specifically stimulus, on the point of light runners. In the 90s, there were similar findings in the premotor cortex in macaques. In the latter neurons, it was surprisingly to neurons with a motor function, and therefore they were called mirror neurons.