Behavioral and Brain Sciences

Continuing Commentary
Commentary on Esther Thelen, Gregor Schöner, Christian Scheier, & Linda B. Smith (2001). The dynamics of embodiment: A field theory of infant perseverative reaching. BBS 24(1):1–86.

Is the concept of object still a suitable notion?

Marie-Dominique Giraudo a1 and Andrew B. Slifkin a1a2
a1 UMR 6152 “Mouvement et Perception,” Faculté des Sciences du Sport, Université de la Méditerranée et Centre National de la Recherche Scientifique, 13288 Marseille cedex 9, France
a2 Department of Psychology, Cleveland State University, Cleveland, OH 44115


The model and framework presented in the target article by Thelen et al. is an interesting effort that is able to account for the contextual variability in the A-not-B performance of 7–12-month-old infants. In the process of developing their framework, the authors discounted the concept of object as a useful notion in discussions of A-not-B performance. For Piaget and other developmentalists, the main evidence for the acquisition of the concept of object was the disappearance of A-not-B errors after age 12 months. However, the Thelen et al. model makes predictions of A-not-B outcomes over a much shorter, trial-to-trial time scale. Given the mismatch in the time scales over which analyses in the two approaches have been based, we wonder if the challenge to the concept of object has been misplaced.