ASHTON, R. Aspects of Timing in Child Development. CHILD DEVELOPMENT, 1976, 47, 622-626. The importance of timing in the control of skilled action is stressed. It is concluded that such control is exercised by an internal or endogenous time-reference system, possibly based on rhythmical hippocampal activity. The concept of an endogenous time-marker system is then applied to explain findings from soothing and conditioning studies of infants. The final section deals with the problems facing the child during socialization when he has to integrate his activities into those of a society with its own temporal rhythm.