Who can you trust?

Imagine this:

You are trying to decide whether someone (a business associate, a date, a salesman, it doesn’t matter) can be trusted with an important part of your life. You are allowed to ask them just one question. What would it be?

In his book Born to be Good, neuropsychologist David Keltner gives this advice: ask them to tell you about their most embarrassing experience, then watch carefully as embarrassment “ripples” across their face.

But isn’t embarrassment about only the most superficial parts of our lives; things like being polite, having good manners, leaving  our nose alone in public?

No, says Keltner. The visible signs of embarrassment  are fleeting indications of how much that person respects the judgement of others*. An averted gaze, a head turn, a coy smile, these things reveal how much the person truly cares about the rules that bind us all together, both in our one-to-one relationships and in society at large. They are “potent non-verbal clues … to an individual’s commitment to the moral order”.

* If this sounds like a few lines from the US TV series Lie to Me that’s because Keltner did postgraduate work with Paul Ekman, whose pioneering studies of facial micro-expressions inspired the  programme (and much more, of course).