Evaluates the epigenetic landscape metaphor in light of behavioral development. Cites two common errors in integrated models of behavior and biology: (1) fixing behavior as structure, thereby robbing it of dynamics and plasticity; and (2) assuming that a single optimal trajectory applies to development of organisms or systems. (BC)

Changes from the expected life course can arise from at least three different reasons in longitudinal work: developmental novelty, errors in diagnosis, and errors in expectation. This longitudinal study examined the social development of 220 fourth graders and 475 seventh graders over a period of 10 years with over 98 percent of the original…