Different actors, different personas, but most significantly, different hair: so goes the evolution of the character we insist on calling Doctor Who. (We're masochists for outraged, pedantic lectures from geeks.) For a time-traveler, the Doctor sure has followed the hairstyle trends of his time, hasn't he? Keep that in mind as you try to match the hair with the Doctor.
Answers are here. Please post your guesses, speculations, or arguments below! But know this: the Trivial Eye is presented for public amusement and no prizes are offered other than that familiar feeling of aggravation that so much of your mind is occupied by useless trivia.