Book Description:
Temperament has been a central element of the on going effortto describe the distinctiveness of persons at every stage ofdevelopment. Many researchers have examined the relations oftemperament to emotions, behavior, and adjustment generally.Fewer studies have focused primarily on the nature and structureof temperament, however, and even fewer have examinedthe developmental course of temperament. This Monographreports a significant exception. The authors undertook theoreticallyrelevant behavioral, biological, and self report assessmentsof a sample of 14 to 17 year olds who had been classified intoone of four temperamental groups at 4 months of age. Infanttemperamental categories were based on observed behaviorto a battery of unfamiliar stimuli. The infants classified as highreactive (20 percent of the sample) displayed vigorous motoractivity and frequent crying. Those classified as low reactive (40percent) displayed minimal motor activity and crying. About 25percent of the infants, called distressed, showed minimal motoractivity but cried frequently, and 10 percent, characterizedby vigorous motoricity but little crying, were called aroused.Previous evaluations of these children at 14 and 21 months,and 4, 7, and 11 years had revealed that those children initiallyclassified as high reactive were most likely to be avoidant ofunfamiliar events at the early ages and emotionally subdued,cautious, and wary of new situations at the later ages. Bycontrast, initially low reactive children had been the leastavoidant of unfamiliarity in the second year and most emotionallyspontaneous and sociable at the later ages. At age 11years, assessments also had revealed that initially high reactivechildren were more likely than the low reactive participants todisplay right hemisphere activation in the EEG, a larger evokedpotential from the inferior colliculus, larger event relatedwaveforms to discrepant scenes, and greater sympathetic tonein the cardiovascular system. In the follow up of these individualsreported here, adolescents (14 17 years of age) who hadbeen classified as high reactive in infancy were more likely thaninitially low reactive participants to display sympathetic tonein the cardiovascular system, to combine a fast latency with alarge magnitude of the evoked potential from the inferior colliculus,and to show shallower habituation of the event relatedpotential to discrepant visual events. Moreover, compared totheir low reactive agemates, initially high reactive adolescentsmore often reported being subdued in unfamiliar situations,experiencing a dour mood and anxiety over the future, and beingreligious. An important finding is that behavior and biology weremore clearly dissociated in adolescence than at earlier ages.However, infant temperamental category at 4 months remaineda powerful predictor of behavior in adolescence, suggesting thatthe features that characterize the two temperamental biases byinitially high and low reactive are not completely malleable tothe profound effects of brain growth and experience.
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