Lawrence M. Ward, University of British Columbia, Vancouver, BC, Canada
Robert L. West, Hong Kong University, Hong Kong, China

Abstract: Does the unpredictability of human behavior arise from randomness, from deterministic but chaotic processes, or from humans' use of (possibly nonlinear deterministic) heuristics in coping with complicated situations? One way to find out might be to see whether humans can behave chaotically when asked to do so. Previous work showed that when humans are asked to generate a series of numbers according to a particular chaotic equation they can do so but not in exactly the way the equation would generate them. Nonetheless, their series of guesses do contain nonlinear deterministic structure, which is one indication that they may be generated by a chaotic process. Series of guesses generated by a computer simulation of a model that simulates the heuristic thought processes of the humans making the guesses also contain nonlinear deterministic structure of the same order as the logistic the humans are attempting to mimic. Thus, when faced with a chaotic process, humans seem to cope by using a heuristic process that approximates the chaotic process within the limitations of human memory and performance.

Keywords: chaos, nonlinear forecasting, logistic, heuristic, computer simulation