Machiavelli was quite wrong about power. It isn’t something nasty that you get by being as devious as possible. Being feared is not better than being loved. And people aren’t, in general, fickle, hypocritical and greedy of gain.

According to Dacher Keltner, a psychology professor at the University of California, Berkeley, power is something benign, a force for good, given willingly by decent humans to each other. He has reached this most soothing of conclusions after two decades spent studying power in the lab, the office and the dorm. He has looked at how people get it — and what happens when they have it.

Keltner starts by defining power in the usual way — as the ability to alter the states of others — but then interprets it more broadly as the underpinning of every relationship. People get power, he thinks, not by force, but by winning the approval of others. They do that not by frightening them, but by acting in accordance with the greater good.