This paper reports the first phase of a research program on visual perception of motion patterns characteristic of living organisms in locomotion. Such motion patterns in animals and men are termed here as biological motion. They are characterized by a far higher degree of complexity than the patterns of simple mechanical motions usually studied in our laboratories. In everyday perceptions, the visual information from biological motion and from the corresponding figurative contour patterns (the shape of the body) are intermingled. A method for studying information from the motion pattern per se without interference with the form aspect was devised. In short, the motion of the living body was represented by a few bright spots describing the motions of the main joints. It is found that 10-12 such elements in adequate motion combinations in proximal stimulus evoke a compelling impression of human walking, running, dancing, etc. The kinetic-geometric model for visual vector analysis originally developed in the study of perception of motion combinations of the mechanical type was applied to these biological motion patterns. The validity of this model in the present context was experimentally tested and the results turned out to be highly positive. With very few exceptions, research on visual motion perception has dealt with simple patterns of mechanical motions. As a rule, rigid objects in rotary or translatory motion have been chosen as the distal stimuli, and the proximal stimulus patterns investigated have been projections of such objects in motion. Stimulus patterns representing living animals in motion have rarely been studied. Michotte's (1963) study of perception of larva motion may be pointed to as an important exception. This relative lack of studies concerning visual perception of animal and human motion patterns has no relation to the biological importance of this type of visual perception. It seems evident that, throughout animal evolution, valid information about other animals' motion has achieved a very high survival value. Our everyday experience also tells us that human vision not only detects motion directions in man and animals, but also distinguishes different standard types of limb motion patterns. We immediately see whether a person is walking, running, or dancing, and also if he is moving forward with identical speed in these three cases.
In REF , the author demonstrated that humans can easily recognize events from the motion of a few human body joints.
Visual perception of biological motion and a model for its analysis
Perception & Psychophysics
Psychology