This paper describes a study comparing the development of children reared in a communal environment with that of children from upper-middle-class home environments. Variables considered were cognitive development and academic achievement. Subjects consisted of 39 children, 2 1/2 to 6 1/2 years of age, reared communally from birth, and 39 home-reared children matched for age and sex. The Synanon community provided an example of child-rearing by multiple caregivers. Up to 20 different caregivers per year rear the children, who live in peer groups from birth to adulthood. Parents average approximately three hours a week with their own children. The home-reared group was comprised of children from upper-middle-class, two-parent families, with the mother as primary caregiver. Cognitive development was assessed with the McCarthy Scales of Children's Abilities. In addition, the 5- and 6-year-olds were given the Peabody Individual Achievement Test. Results indicate that multiple mothering, per se, is not detrimental to cognitive development. It was also shown that IQ can be influenced through environmental change, increasing to significantly above the average. Significant preliminary evidence showed steady increases in Synanon children's IQs from age 2 to 6, while home-reared children remained farily constant in IQ across age. The study also demonstrated that 4-year-olds can successfully be taught first grade materials. (Author/BF)