PantsThe article “Q: Why Do We Wear Pants? A: Horses” (by Alexis Madrigal for The Atlantic) quotes evolutionary biologist Peter Turchin:
“Historically there is a very strong correlation between horse-riding and pants,” Turchin wrote in a blog post this week. “In Japan, for example, the traditional dress is kimono, but the warrior class (samurai) wore baggy pants (sometimes characterized as a divided skirt), hakama. Before the introduction of horses by Europeans (actually, re-introduction - horses were native to North America, but were hunted to extinction when humans first arrived there), civilized Amerindians wore kilts.”As an example, ancient Romans (after 284 AD) were aware of pants, but did not wear them:
Trousers — considered barbarous garments worn by Germans and Persians — achieved only limited popularity in the latter days of the empire, and were regarded by conservatives as a sign of cultural decay.
HatsIn the early 1900s, most men in the United States wore hats. Since then that has changed. The article “Who Killed Men's Hats? Think Of A Three Letter Word Beginning With ‘I’” (by Robert Krulwich for NPR) explores several possible explanations, the most likely one being:
Until cars became the dominant mode of personal transport, there was no architectural reason to take your hat off between home and office. With Dwight Eisenhower's interstate highway system came cars, and cars made hats inconvenient, and for the first time men, crunched by the low ceilings in their automobiles, experimented with hat-removal, and got to like it.That explanation would conform to a psychological law: Even slight hurdles can significantly influence decisions.