Planet Earth has a serious deficiency of positive psychology – or, at any rate, its workplaces do: so says US motivation expert Shawn Achor in a funny and slick presentation recorded for the online masses.

“When I turn on the news,” he says, “it seems that the majority of the information’s not positive – in fact, it’s negative. Most of it’s about murder, corruption, diseases, natural disasters – and very quickly, my brain starts to think that that’s the accurate ratio of negative and positive in the world.”

This malaise, Achor argues, clouds our thinking on most typical days at work, driving us into the grip of “medical school syndrome” – something that trainee doctors suffer when they’re scanning lists of symptoms for various conditions and gradually convincing themselves that they have all of them.

But that psychological clutter needs an urgent clearout. According to Achor, only 25% of job successes are determined by IQ. The remaining 75% are determined by optimism levels, and most importantly by an ability to see stress as a challenge, not a threat.

Only by rewiring our brains, he says, can we turn this situation around. Instead of seeing happiness as a goal somewhere over the horizon, why don’t we harness it as an engine for motivating us in the present?

Here is Achor’s presentation on the benefits of positive thinking – with a lot of excellent jokes worked in.

Find out more about Shawn Achor’s work here

See more TED talks on business here