They're kinda linked if you think about it a little deeper.

Psychology is interesting to study, just stay away from sigmund frued and other jews. Jung is good reading but aside from that I can't name anyone else off the top of my head.

The physiognomy is a biological thing that likely affects the psychology or mentality of people since bad physiognomy is due to bad genetics and the body and mind are both affected if a person has bad genes.

The most obvious thing is usually symmetry since asymmetrical faces/bodies are a good sign of bad genes but there are other traits as well. The more you see pictures of the people connected to what they do the better you'll get at figuring things out.. which is almost certainly why jewish media is selective about when they put pictures of offenders in news articles these days.