Predictors of children's cortisol activation during the transition to kindergarten.

The purpose of the present study was to identify predictors of children's cortisol responses after the transition to kindergarten. Morning salivary cortisol was measured in 50 children 1 week before and 1 week after they began kindergarten. Children who experienced a greater degree of change between their preschool and kindergarten routines and who had infrequent preschool experiences exhibited the largest increases in morning cortisols after kindergarten entry. Children whose parents indicated that they would have an easier, rather than more difficult, time adapting to kindergarten also tended to be more reactive in their morning cortisol levels after kindergarten entry. Results provide new insight into experiential and individual-difference factors that predict children's physiological reactivity and self-regulation during times of transition and potential stress.