Longitudinal data concerning fear responses in 30 boys and 30 girls observed from ages one month to 8 1/2 years suggest that in males--but not in females--a predisposition to a particular level of fearfulness is set by events that occurred before 6 months of age. (Author/MG)

The early development of wariness toward unfamiliar persons and novel objects is examined. Data are based upon the reactions of 32 infants who were repeatedly observed, over the age period 3 to 9 months, as they responded to the near approach of a stranger, and to a variety of new objects. Signs of wariness toward unfamiliar persons began to…