Examined the environmental and behavioral antecedents associated with neuroticism (N) and extraversion (E) in 1,931 undergraduate Ss, using an autobiographical data form and the Maudsley Personality Inventory. Clusters associated with N conveyed information about perceived parental expectations and evaluations, mode of disciplinary control, parental affective reactions, and family relations. Behaviors antedating N included emotional functions, adjustment modes, psychological needs, and social maturity. With regard to E, 45 clusters resulted, dealing with parental training, standards and socialization practices, intimate behaviors, socioeconomic indicators, and relations with important others. Behavioral antecedents of E included reliance on people, extensive participation in diverse activities and leadership tendencies, self-reliance, inquisitiveness, and interests in many subjects. (PsycINFO Database Record (c) 2006 APA, all rights reserved)