The abstract and the article say, "The estimates were correlated strongly with the facial width-to-height ratio of the stimulus faces and with the actual aggression of the men," but without paying for the article, I can't find out how strongly correlated.
The article suggests that this means looking at somebody's facial shape may be a reliable indicator of how aggressive the person is likely to be. Could be. I'd want to read the whole thing before I started shying away from people with wide faces.
This brings to mind a story about foxes. A Russian scientist wanted to breed tame foxes for their fur. He selected the ones that didn't run away when he came near and then the ones that let him touch them, each generation breeding the tamest to the tamest.
They got tame. They also lost their fox smell, got mottled fur, started to wag their tails when happy and put their ears down when rebuked. They started to bark.
It turned out that selecting for tameness meant inhibiting the production of adrenaline, and it further turned out that adrenaline was involved in lots of other processes in the fox (and presumably the wolf, when it morphed into dogs), such as fur color, vocalization, and tail wagging.
In the case of wide faces, you have to wonder if maybe an increase of adrenaline (or some other hormone) incidentally is related to how wide the face grows in utero.
The morals ares that:
- the body and brain are gawdawful complicated
- lots of behaviors are biologically influenced
- unexpected weird stuff can happen when you play biochemist.