Genetics and the Trait Theory are imperative to the  study of psychology, as it gives reasoning as to why we habitually behave the way we do: it is because of our genes and heredity. With this theory, psychologists can analyze why people have the personalities they do (it stems from their parents according to this theory). I know this as there have been tests that have put identical twins separated at birth in a blind experiment where they both ended up living nearly identical lives, supporting the idea that genetics do indeed have a huge part in people's personalities. Evidently, people's habitual behavior could be then studied based on their parent's genes and their own apparent personalities. Through these key aspects psychologist can trace back what led to someone's identity.