STEREOTYPED HUMAN-BEHAVIOR - A NONLINEAR DYNAMICAL ANALYSIS

Some forms of stereotyped human behavior seem to occur randomly in tim e. A dynamical analysis of several topographies demonstrates that whil e such stereotypies have the spectral characteristics of random noise, the rate at which each subject exhibits his/her stereotypy is to some extent predictable and, unlike uncorrelated noise, prediction accurac y declines with increasing prediction interval. Rhythmic stereotypies appear to be more predictable than nonrhythmic topographies but both s how a similar decline in prediction accuracy. Furthermore, the distrib ution of interresponse times exhibits self-similar behavior. These res ults point to a deterministic, rather than stochastic, origin for the variability of observed rates of stereotyped behaviors.