The first thing Pythagoras did when young men applied to enroll in his school was to “physiognomize” them. This word means assessing a person’s character and disposition through inferences drawn from his facial appearance, his expression, and the form and bearing of his body as a whole (Aulus Gellius, Attic Nights 1.9).
What? Haven’t we all read about how Socrates was belittled by the physiognomist Zopyrus, who claimed to be able to discern a person’s nature and character from his body, eyes, face, and forehead? He declared Socrates to be stupid and slow-witted, since he did not have dimples in his neck above the collarbone, that part of his body being blocked up and obstructed. He added that Socrates was a womanizer; Alcibiades is said to have hooted with laughter when he heard that (Cicero, On Fate 10).
Why are humans the most thoughtful of all animals? Is it because they have very small heads in proportion to their body size? … People with small heads are more thoughtful than people with large heads (Pseudo-Aristotle, Problems 955b).
People with small faces have small souls, like cats and monkeys (Pseudo-Aristotle, Physiognomonica 811b)
Why is it that those with a body bigger in the region below the navel than up towards the chest are short-lived and sickly? Is it because the stomach, being small, is cold, and therefore does not digest food readily, and tends to retain waste products? People like that are vulnerable to disease (Pseudo-Aristotle, Problems 898a).
If the distance from the lowest point of a person’s chest to his navel is greater than that to where his neck starts, he is greedy and gluttonous. Praise a large and firm chest. A chest that is thin and weak indicates a petty soul and cowardice, a fleshy chest indicates ignorance and clumsiness. Anyone with a big chest covered with wobbly and pendulous flesh is lecherous and a drunkard (Adamantius, Physiognomonica 2.15).
Some Stoic philosophers think that anger is aroused in the chest when the blood boils around the heart. The reason why this particular location is assigned to anger is simply that the chest is the warmest part of the whole body. Anger builds up only gradually in people with excess moisture [i.e., in the humors], because they do not have a store of heat, but acquire it through movement; this is why the angry outbursts of children and women are fierce, but not very consequential, and can be sparked by trivial causes. During those periods of life when dryness predominates among the humors in the body, anger is vehement and strong, but stable, without growing worse, because cold is then taking over from heat, which is waning. Old people are bad-tempered and querulous, as are sick people and those whose heat has been used up either through exhaustion or through loss of blood. The same applies to those who have wasted away through thirst or hunger, and to the anemic, the badly nourished, and the weak. Wine inflames angry passions, because it increases heat. Some people boil over when they are drunk, others when they are just slightly tipsy: it depends on the individual. This is also why red-haired people and those with ruddy complexions are particularly susceptible to anger: their blood is in a constant state of restless motion (Seneca, On Anger 2.19).