Dynamical Patterns in the Development of Clapping Paula Fitzpatriek Assumption College and CESPA, University of Connecticut R. C. Sehmidt College of the Holy Cross and CESPA, University of Connecticut Jeffrey J. Lockman Tulane University FITZPATRICK, PAULA; SCHMIDT, R. C ; and LOCKMAN, JEFFREY J. Dynamical Pattems in the Devel- opment of Clapping. CHILD DEVELOPMENT, 1996, 67,2691-2708. The development of a complex rhythmical behavior—clapping—is modeled using a formal, explicit model of coupled oscillator dynamics. Even though this behavior manifests a good deal of nonstationarity and high variability within and across subjects, results indicate that these properties may be dynamically modeled quantitatively as well as qualitatively. Results suggest that clapping goes through a less stable period of relative coordination between 3 and 7 years before more stable absolute coordination is achieved. Nevertheless, in that the clapping behavior is affected in highly predictable ways by inertial loading ofthe limbs, the same underlying dynamic seems responsible for the coordina- tion of both the younger and older children. Developmentally, the behavior of the coordination variable (relative phase) changes from a nonconstant magnitude in younger clappers to a constant magnitude in older clappers. These results suggest that development of proficiency in rhythmic motor skills displays developmental changes that can be understood well in dynamical terms. There has been a growing interest re- and chosen most often. Changes in circum- cently in using dynamical theory as a means stances (e.g., task, intention, environment, for understanding and modeling developing age) can alter the stability characteristics of systems (Fitzpatrick, in press; Thelen, 1995; those behavioral patterns and resuit in the Thelen & Smith, 1994; Turvey & Fitzpat- appearance of new behavioral modes, rick, 1993). A defining feature of developing systems is that they change behaviorai In the dynamicai modeiing of behav- modes. Dynamical theory is particularly ioral systems, rhythmic interlimb coordina- well suited for modeling developing sys- tion patterns have been a main focus on tbe tems due to its reliance on general princi- formai modeiing efforts. This is due in part pies of stabiiity and change to expiain the to the fact that coordination patterns in emergence of new behavioral organizations, which the two limbs move at a common fre- In broad strokes, a biological organism is a quency are basic to many everyday activi- complex physical system. Its behavioral pat- ties. Proficiency in rhythmic behaviors terns can be thought of as attractive states seems to be intimately tied to the ability to tbat sirise from an interplay of forces and mu- bring simpie motor rhythms (repetitive pat- tual influence of the very many components terns with fixed temporal structure) under of this system. Under certain circumstances, voluntary control to produce coordinated particular patterns are preferred and act as behaviors with complex temporai sequences attractors in the sense that they are stabie (e.g., von Hofsten & Ronnqvist, 1993; Rob- The research reported here was part of a dissertation presented to the University of Connect- icut by Paula Fitzpatrick. The research was supported in part by a Doctoral Dissertation Fellow- ship and an Extraordinary Expense Award from the University of Connecticut, NSF grant BNS 91-09880, and LEQSF Grant 92-95-RD-A-23 awarded to Richard Schmidt. The flrst author was also supported by an NSF Predoctoral Fellowship during data collection. We would like to thank Lisa Sherman for her help in data collection. Correspondence concerning this article should be addressed to Paula Fitzpatrick, CESPA, U-20, Department of Psychology, 406 Babbidge Road, University of Connecticut, Storrs, CT 06269; e-mail pfltz@UConnVM.UConn.Edu. [Child Development, 1996,67,2691-2708. © 1996 by the Society for Research in Child Development, Inc. All rights reserved. 0009-3920/96/6706-0027$01.00]