Abstract
Using video clips collected for a video encyclopedia of infancy (Sasaki, 2008), a case study was conducted on the changing processes of a toddler's behavior. Naturalistic observations were conducted of the child gathering toy blocks in a container, between the ages of 14-24 months. This investigation of the environment surrounding the toddler's behavior revealed that properties of the surface layout affected his postural variations that made possible goal-directed action of gathering blocks in a container. In addition, the boy's behavior was regulated in such a way to maintain an invariant affordance relationship between detached objects and the child. Analysis of changes in his activities indicated that that awareness of meaningful properties of the environment allowed actions to be selected among those that are afforded to flexibly deal with context-conditioned variation.
