From your walk and your body odour to the shapes of your ears and your backside, scientists are finding many surprising ways of identifying you from the other seven billion people in the world.
All humans are born with ten fingers, ten toes, one nose, one mouth, and two ears (unless affected by a congenital disorder). Those physical traits are fixed; they are hard-wired in the genetic makeup of humans. This is a result of selective evolution. The fixation of these physical traits has increased our “fitness”, i.e. our reproductive success.
This is different with personality. We all have. We are all different from each other. Each one of us represent a unique mix of different personality traits. No other person has the same mix of big five personality traits (and their facets) as you have. What kinds of evolutionary processes maintains this variation in personality? Why are we not all born with the same personality?