PERRY, DAVID G.; WHITE, ADAM J.; and PERRY, LOUISE C. Does Early Sex Typing Result from Children's Attempts to Match Their Behavior to Sex Role Stereotypes? CHILD DEVELOPMENT, 1984, 55, 2114-2121. Most cognitive theories of sex typing-including cognitive social learning theory and cognitive-developmental theory-suggest that sex typing results, in part, from a 2-step process: children are thought to acquire stereotypes of sex-appropriate behavior, primarily through observational learning; they are then thought to adopt as their own preferences the behaviors they have encoded as appropriate for their own sex. To determine if very early sex typing occurs in this sequence, 2-, 3-, 4-, and 5-year-olds were tested both for knowledge of sex role stereotypes and for preferences for sex-typed activities. Contrary to the hypothesized sequence, boys' acquisition of sex role stereotypes lagged behind (by about 1 year) rather than preceded their development of sextyped preferences. Girls' data neither clearly refuted nor clearly confirmed the hypothesized sequence. A secondary finding was that boys displayed equally strong tendencies to endorse same-sex activities and to reject cross-sex activities, whereas girls unexpectedly displayed a stronger tendency to reject cross-sex behavior than to endorse same-sex behavior.