At two, children are just beginning to discover the world. They are much more interested in learning how to work a door knob or how to pour water out of a pitcher and fill it up again than they are in playing with other children. As a child turns three, many of these big issues are resolved. Now a child is ready to turn to other children. In fact, the year between three and four is a highly social age.
Children learn to negotiate, compromise and share with their peers.
At this time, boys and girls play together beautifully. As a chid approaches four, there is a marked shift in behavior. This is the time that gender identification becomes very strong. In fact, girls stick together in the block area, as well as the dramatic play area. This is also true for boys.