Differential adult response to the dependent behaviors of young girls and boys has been widely reported in the literature. The present study was an experimental investigation of the role of adult response patterns in shaping and maintaining independent behavior in preschoolers. A two-group design using random assignment was used to examine environmental control of independent and dependent behaviors, defined as task persistence and exploration, and proximity-seeking and socialization of attention, respectively. Subjects were 20 3- and 4-year-olds, 11 females and 9 males. Results indicated that independent and dependent behaviors are both strongly under the control of environmental contingencies in both boys and girls. Implications of these results for the theoretical understanding of sex-role development and women's mental health problems are discussed.