Serve coffee.

The next time you’re offered a drink in a business meeting, think carefully before choosing between a cup of coffee and a glass of water. Because research suggests that a shot or two of caffeine does more than just keep you awake and alert; it can actually help to improve your ability to influence and persuade.

Allow me to explain.

Caffeine is well known to enhance attention, vigilance and even cognition. However, when I was in Brisbane a few weeks ago I came across a study by Pearl Martin of the University of Queensland. She discovered that an expresso could give you more successo, whilst an Americana could get you much farther. Don’t you just love these modern scientists? In her experiment, she got volunteers to read an argument on the controversial subject of euthanasia and then attempted to change their views on the matter. As always, there was a certain amount of sleight of hand at work.

Firstly, all the participants chosen were known to agree with the concept of euthanasia, even though they were told that that the group were split roughly half and half either against or in favour. Secondly, only half the group were given a caffeine-rich drink to consume, whilst the other half were actually given a placebo containing no caffeine. I think I’ve been to that coffee shop in Harrogate.

Then the fun really started when the researchers tried to convince participants to change their mind about the issue by giving them six stories to read which argued against euthanasia. What’s more, the experiment was conducted ‘double-side-blinded’ which meant that not even the researchers knew who had taken the caffeine and who had taken the placebo. When asked afterwards for their attitude to voluntary euthanasia, it was discovered that those who had drunk caffeine were more influenced by the persuasive message than those who’d had the placebo. One even tried to sign up his grandmother who was only 57 at the time. Only kidding.

Participants were then asked about their attitude towards abortion since someone who disapproves of euthanasia is also likely to disapprove of terminations. Again, they found a similar result. The persuasive message had spread to a related idea and the effect was strongest amongst those who had consumed caffeine.

So there you have it in a nutshell. Or rather a coffee bean. Caffeine really does do more than keep people awake and alert. It also makes them more likely to be persuaded to your way of thinking. But exactly why is that? Well, the reason that a lot of persuasive messages pass us by is simply because we’re often not paying enough attention to them; we’re usually thinking about ourselves, our problems or our pleasures. But by increasing our arousal through caffeine, it makes us process incoming messages more thoroughly, potentially leading to increased persuasion.

So the next time you want someone to agree with you, treat them to a double expresso with an extra shot for good measure.