Biological systems are inherently "noisy". Although researchers have long considered such noise to reflect random variability, insights from chaos theory suggest that such variability, while unpredictable, may arise from simple, deterministic mechanisms. Measures of nonlinear variability (e.g., fractal dimension, Lyapunov exponents) offer new methods of characterizing such variability and promise a novel way for researchers to think about the ubiquitous noise found in biological and behavioral data sets. Examples of applications of nonlinear dynamics from such diverse fields as meteorology, population biology, epidemiology, economics, cardiology, traffic control, musicology, and clinical psychology will be briefly discussed. In addition, original data from two experiments (left versus right hand differences in finger tapping; effects of caffeine on long-term variations in mood and arousal) will be presented, providing demonstrations of the challenges and benefits in applying the techniques of nonlinear dynamics to behavioral topics.

Professor Christman received his B.A. in 1982 from the University of Michigan and his Ph.D. in 1988 from the University of California at Berkeley. His research has focused on the topics of cerebral asymmetry, handedness, and visual perception. This work has resulted in 23 journal articles, four chapters, and one book, Cerebral Asymmetries in Sensory and Perceptual Processing (1997; North-Holland). He is an Associate Professor of Psychology at the University of Toledo and is a member of the Editorial Board for the journal Brain and Cognition.