Periodically, explainers and demonstrations of something called “hair theory” pop up on TikTok and start a conversation about how hair style affects how people are perceived. Lately TikTok creators ...

Leaving the house without brushing or styling your hair? That's the whole idea behind "depression hair," a "just-got-out-of-bed" hairstyle that's the opposite of neat blow-drys and other hair fancies.

It started slowly, with handfuls of hair circling the plug hole in the shower. Then eventually British bodybuilder Tracy Kiss began to notice she could see her scalp when her hair was wet. “I always ...