Certain elements of childhood -- school, play, homework -- are often considered universal by those who live in industrial societies. Evolutionary anthropologist Dorsa Amir draws from her time living in foraging societies to explain how the post-industrial experience of childhood is a relatively new development for humanity with wide-ranging impl...

You know that little pink thing nestled in the corner of your eye? It's actually the remnant of a third eyelid. In humans, it's vestigial, meaning it no longer serves its original purpose. There are several other vestigial structures in the human body, quietly riding along from one of our ancestor species to the next. But why have they stuck aro...