Rudiments of Infant Temperament: Newborn to 9 Months

Temperament was assessed for newborn twins, using a comprehensive neonatal exam that focused on irritability, resistance to soothing, activity, and reinforcement value. The same infants were later assessed at 9 months in a structured laboratory setting, where measures of emotional tone were obtained under a wide variety of instigating conditions. Summary ratings of emotional activity were compiled for each infant, representing the preponderant reaction of the infant in both settings. Individual differences were markedly evident, ranging from wailing distress to smiling and contentment. The neonatal variables correlated significantly with emotional tone at 9 months ( r s in mid-0.20 s, p < .05), and a further analysis revealed a generalized multiple correlation of R = 0.32 between the neonatal variables and the 9-month measures of temperament. When extreme groups on emotional tone were selected at 9 months (crying and distress vs. smiling and contentment), the groups were significantly discriminated by their neonatal scores, with 70% of the infants being correctly assigned to the appropriate extreme group. Overall, the irritable, difficult-to-soothe neonate was likely to be fussier and more distressed in the lab assessment than the more tractable neonate. The results affirmed a significant predictive linkage between neonatal behaviors and later measures of temperament and thus gave credence to the premise of some stability in infant temperament. Emotional activity appeared to be the core dimension stretching over ages, and it is discussed in relation to other formulations of infant temperament. The results demonstrated the utility of a comprehensive neonatal assessment specifically designed to measure temperament, which could be coordinated with laboratory measures of temperament at later ages.