The powerful and ambivalent feelings aboutsiblings play a significant role indevelopment. A study of sisters, in particular,challenges many common assumptionsabout girls’ psychology, and offers aframework for new understanding of arange of human experience, from tiffs onthe playground to jealousy in theboardroom.Dr Terri Apter is a psychologist and writerand Senior Tutor of Newnham College. Herbooks on family dynamics, identity andrelationships have received international acclaim