Alfie Kohn

Although it's not widely known, the word stress, when used to describe someone's emotional state, is actually a metaphor. Originally, the term was limited to scientific study of metals and other materials. It referred to the "strain or deformation" that result from excessive force. A steel bar is capable of tolerating only so much stress before it snaps.

So, what is it that, figuratively speaking, creates a comparable force on children ? And what happens to them when they "snap" ?