According to a recent scientific paper, artificially enhancing the appearance of male barn swallows, thereby making them more attractive to females, upped their testosterone and even trimmed their weight.
“Other females might be looking at them as being a little more sexy, and the birds might be feeling better about themselves in response to that,” said study co-author Kevin McGraw, an evolutionary biology professor at Arizona State University.
[…]
“It’s the ‘clothes make the man'” idea, [lead author Rebecca] Safran said. “It’s like you walk down the street and you’re driving a Rolls Royce and people notice. And your physiology accommodates this.”
Obviously, one shouldn’t be too quick to draw conclusions about humans from a study of birds, but the underlying mechanism shouldn’t be ignored: How a gentleman dresses affects how others treat him, which in turns affects his mood and even his personality. Izzy, for instance, has noticed that when he is well-turned out in a jacket and tie, strangers treat him better, which makes him more chipper and gracious than he would be otherwise. While it’s an old idea that clothes make the man, this study helps to explain how that can occur even if the man is unaware of what he is actually wearing.