Infancy, birth-2 (first feelings of belonging, vocalize, touch, smile); Early Childhood, 2-5 1/2 (preschool, playdates, play in groups); middle childhood, 6- 12/13 (school age, active parents make more harmonious ties with peers, peer group is attractive); adolescence, 12/13-18 (a few BF's, peer group escalates, need for responsiblitiy and recognition)