Gender recognition is one of the earliest cognitive developments in a child. Many scholars in both the sciences and humanities have been very interested in researching the origin of gender recognition in young children and the effects it has on the development of social life. Some scientists have determined that gender is not something that is "hardwired" into your brain (Elliot, 1), it is a trait that is learned through experience and how you are raised. Young children learn the roles they take on in their playgroups, whether as boys or girls, from interactions with the influential adults in their lives and from the limited social experiences they have encountered. “Knowledge of one's sex and the sex of others can influence behavior” (Campbell, 8). Some scientists have concluded that infants begin to “categorize themselves, objects, and characteristics as girls or boys within the first 24 months of life” (Freeman, 357). This is the time when the child will begin to distinguish what is like or different from him and the concept of “'mine' and 'not yours'” will come into play (Levine, 456). After this develops, children will begin to expand their gender-specific play preferences within the first 36 months of life. This shows that you do not need a complicated and fully developed mind to understand the social structure of your society. “Both gender identity and sex differences in behavior emerge largely in the first three to four years of life” (Campbell, 1). This means that by the age of three, children have already limited themselves to the limited and rigid restrictions of their gender. The effects manifest themselves in various ways depending on the child. Color is the most influential part of a young child... in the center of the card... encourages boys to explore, responding positively to girls' calls for help. ” (Levine, 456). This creates girls who are good communicators and very emotionally aware, but not always very self-sufficient. Some of these traits manifest themselves in the conflicts that are inevitable when play is involved. One of the biggest recent discoveries is that “children…, as young as four years old,… use social ostracism and other relatively subtle manipulative tactics that are intended to damage another's self-esteem or social standing” (Ostrov, 256). it is a truly miraculous discovery because it shows that children are able to carry out indirect aggression earlier than decades ago, demonstrating that aggression in children is shifting from a physical attack to a more mental attack As “kids emphasize dominance while girls emphasize intimacy,” they handle their aggression differently.