Don't take candy from strangers

This is one of the first lessons we teach children. Don't talk to strangers, and never ever take candy from a stranger. But why do we have to tell this to our kids? Is it because they're naive? Is it because kids are just too trusting?

As it turns out, small children come equipped with a pretty strong preference to be physically close to their mother, father, and other relatives.  By relatives I mean genetic kin, or those living in such close proximity that they are presumed to be genetic kin. This is why children cry when mom and dad go out to a movie, why it's hard to drop off kids at school for the first time, and why kids are more likely to get homesick than adults. It's a pretty simple rule: Trust people who have the same genes as you.  It's no different in most of the animal kingdom.

Candy is a safety-override switch. The appeal of sugar, particularly once a child is hooked on it, is so strong that it overwhelms the evolutionary mechanism that has tended to keep children safe for time immemorial.  Of course, sugar is what most parents use to control the behavior of their children.  A devil's bargain.

So as not to be a total killjoy, here is Jerry Seinfeld on the power of candy (the first 1:30).  Sometimes it takes a comedian to point out the absurdity of the mundane.