Children vary in the extent to which their development is shaped by particular experiences (e.g. maltreatment, social support). This variation raises a question: Is there no single level of plasticity that maximizes biological fitness? One influential hypothesis states that when different levels of plasticity are optimal in different environmental…

Two experiments explored whether children's correct answers to counter factual and future hypothetical questions were based on an understanding of possibilities. Children played a game in which a toy mouse could run down either 1 of 2 slides. Children found it difficult to mark physically both possible outcomes, compared to reporting a single…

Predictions about the role of contingency, imitation, and affect sharing in the development of social awareness were tested in infants during natural, imitative, and yoked conditions with their mothers at 5 and 13 weeks of age. Results showed that at both ages, infants of highly attuned mothers gazed, smiled, and vocalized positively more during…