Is head size the best way to determine intelligence? Whenever I see a smart person they always have a big head, and it's always really symmetrical as well, on the other hand I have a small head and my intelligence is only average, and I've noticed everyone who is clearly dumb or average has a head size like mine. Obviously there will be exceptions but this seems to be the case most of the time. Also there tends to be more genius men than women and women have small heads compared to men so maybe the head/brain size has something to do with it.