The relation between neonatal and later activity and temperament.

Evidence from several longitudinal studies suggests that individual activity characteristics tend to persist over time and to influence the development of temperamental style. The activity of 50 children whose motility had been monitored by an electronic activity monitor when they were neonates was again monitored by an ambulatory microcomputer when they were 4-8 years old. Additionally, the parents of these children filled out the Behavioral Style Questionnaire by McDevitt and Carey. The results showed that the level of the children's day and night activity was unrelated. The vigor of neonatal movements was later positively related to high daytime activity. Also, the least vigorous infants tended to become the most inactive children during the day. The results further showed that the most active neonates became children who, as perceived by their parents, tended to approach rather than withdraw from new experiences.