The theory that when a member of the male gender automatically looks at the body of a female with blonde hair. And in return, she is automatically more attractive than a brunette or any other hair color counterpart.
Guy 1: Hey bro, did you see that girl?
Guy 2: Hell yeah man! Blonde theory?
Guy 1: Blonde theory!
the theeory that men will choose a dumb blonde woman over a smart, educated woman.
Cheerleaders are perfect examples of the blonde theory.