I have an aunt who gave birth to three sons. She was a stay-at-home mother and my uncle was a very successful lawyer. They raised their children identically, but their children couldn't be more different. My aunt has a saying to explain it, she says "it's in the computer". He believes that we are all pre-programmed for a specific purpose in life before we are even born. This is his unpublished theory, but his scenario does not differ from many others. There are many theories as to why siblings grow up to be so different from each other. One theory is social comparison theory introduced by Leon Festinger in 1954. Festinger's social comparison theory states that we infer our worth (socially and personally) based on how we compare ourselves to others. As a result, we constantly make personal evaluations based on a variety of factors including attractiveness, wealth, intelligence and