We used static facial photographs of 40 men and 40 women to test the relationship between measured IQ, perceived intelligence, and facial shape. Both men and women were able to accurately evaluate the intelligence of men by viewing facial photographs. In addition to general intelligence, figural and fluid intelligence showed a significant relationship with perceived intelligence, but again, only in men. No relationship between perceived intelligence and IQ was found for women.I've long has the impression that you can discern high and low intelligence by the eyes. Intelligent people usually have eyes that either sparkle or burn. I seem to have the latter; it's not uncommon for people to step backward in alarm when I forget to do what I think of as turning down my eyes. Stupid people, on the other hand, tend to have eyes that are dull and unfocused.
We used geometric morphometrics to determine which facial traits are associated with the perception of intelligence, as well as with intelligence as measured by IQ testing. Faces that are perceived as highly intelligent are rather prolonged with a broader distance between the eyes, a larger nose, a slight upturn to the corners of the mouth, and a sharper, pointing, less rounded chin. By contrast, the perception of lower intelligence is associated with broader, more rounded faces with eyes closer to each other, a shorter nose, declining corners of the mouth, and a rounded and massive chin.
It is interesting, though, because the study matches my own experience. I have, on occasion, been taken completely by surprise with the unexpected intelligence of a woman, whereas that very seldom seems to happen with men.