> The Aero Medical Laboratory hired Daniels because he had majored in physical anthropology, a field that specialized in the anatomy of humans, as an undergradu

> The Aero Medical Laboratory hired Daniels because he had majored in physical anthropology, a field that specialized in the anatomy of humans, as an undergraduate at Harvard. During the first half of the 20th century, this field focused heavily on trying to classify the personalities of groups of people according to their average body shapes — a practice known as “typing.” For example, many physical anthropologists believed a short and heavy body was indicative of a merry and fun-loving personality, while receding hairlines and fleshy lips reflected a “criminal type.” Also, for what's it worth, this was during (or at least not too far removed from) a time period where researchers were trying to ascribe all sorts of random characteristics to people based on whether they were "Negroids", "Caucasoids", or "Mongoloids". This says a lot to me about how people thought about physical characteristics back then. If researchers assumed male-pattern baldness was associated with a "criminal type", then it's not a huge stretch to imagine that researchers assumed there was a "pilot type" with a large number of clustered or heavily correlated characteristics.