A cockroach likely has no less brainpower than a butterfly, but we're quicker to deny it consciousness because it's a species we dislike.

We are all born with an innate understanding of interpersonal equity - the idea that if you lend me your rake today, I'll respond in kind when you come to borrow my shovel tomorrow. Or nearly all of us are born with that. Psychopaths aren't.

Is there anything sadder than the foods of the 1950s? Canned, frozen, packaged concoctions, served up by the plateful, three meals per day, in an era in which the supermarket was king, the farmer's market was, well, for farmers, and the word 'locavore' sounded vaguely like a mythical beast.

We're learning how important it is both to preserve sibling relationships if they work and repair them if they're broken. We're also learning a lot about nonliteral siblings - stepsiblings, half-siblings - and the surprising power they can have.

Sisters have ways of socializing brothers into the mysteries of girls. Brothers have ways of socializing sisters into the puzzle that is boys.

Narcissism falls along the axis of what psychologists call personality disorders, one of a group that includes antisocial, dependent, histrionic, avoidant and borderline personalities. But by most measures, narcissism is one of the worst, if only because the narcissists themselves are so clueless.

The mind and the body are inextricably entwined, and rarely are their inseparability clearer than when we're under some kind of mental pressure. The moment we start trying to learn a new skill, make a decision or otherwise think on our feet, our nervous system reacts - with accelerated pulse rate, increased respiration, even sweating.