Let's take the Olsen Twins as an example of siblings who aren't alike.  Sure they both have had their fair share of rehab and problems but they still have different qualities and behaviors.You're probably wondering why we are using them to get our point across  but we have reasons why you and your siblings aren't alike.  Some researchers say siblings may take on different roles to less directly compete for their parents attention.  They also say that small differences between siblings become defining.  If one sibling is not as social as the other, they are automatically labeled as an introvert and start to take on that role.  Do you buy into this?  Are you really that different than your sibling?