A psychologist who's spent decades studying the science of persuasion explains why it's so hard to resist a sales pitch

The science of persuasion — how other people get you to do what they want — can sound simple.

Case in point: If you’ve got a likable salesperson, you’re more likely to buy their product. If that salesperson tells you there’s only one of that product left, you’re even more likely to wind up purchasing it.

Yet if these are really such duh ideas, why can’t we apply them in our daily lives? As in, why can’t we resist the nice salesperson’s pitch, because the truth is we need a $1,000 vacuum cleaner like a hole in the head?

An answer starts to form in Robert Cialdini’s new book “Pre-suasion.” Cialdini is a professor emeritus of psychology and marketing at Arizona State University and the CEO and president of Influence at Work; in his book he offers a look at the invisible interpersonal forces behind our everyday behaviour.

Cialdini explains that it’s psychologically difficult to separate the presentation of a product or service from the merits of that product or service itself.

In other words, it’s hard to disentangle the salesperson’s friendly demeanour from the so-so but expensive vacuum cleaner. If we like the friendliness, we assume we’ll like the vacuum cleaner, and so we buy it.

When he visited the Business Insider office in September, Cialdini gave another example of this principle in action.

If a salesperson were to ask a potential customer to estimate the distance to the sun and then try to sell that person a bottle of mineral water, the person would probably be willing to pay a higher price for that water than if the salesperson hadn’t said anything.

That’s because the distance between the earth and the sun is a big number, and the price of the water bottle seems minuscule in comparison. Psychologists also call this phenomenon the “anchoring effect,” because that first number serves as an anchor to which you compare the next number you hear.

Here’s Cialdini:

“Here’s the thing that we have to recognise and resist. The distance to the sun is entirely unrelated to the merits of this bottle of water.

So that’s what we have to remind ourselves to do. What happened in the moment before we were presented this thing? We have to recognise that there is a ‘pre-suasive’ moment that will move us in a certain direction.

Separate what happened in the moment before we are offered this thing with the thing itself and make the choice based on that differentiation.”

Ultimately, putting these ideas into action — getting better at resisting other people’s influence — comes down to practice. Specifically, you’ll want to practice recognising when you’re in a state of arousal — i.e. when you’re not thinking entirely rationally — and taking a step back from the situation. That way you can separate the presentation from the thing you’re about to buy.

Back to that friendly salesperson for the vacuum cleaner you don’t need. If you find that you’re getting along swimmingly with the person — maybe you both grew up in the same town or you simply find them funny — that’s when it’s time to hit the pause button.

I spoke to Cialdini on this topic a few months ago, at the Psychological Science convention, where he told me:

“Register the fact that you are liking this person unjustifiably well for the short amount of time. Step back from that situation and recognise that you’ll be driving the car off the lot; not the salesperson. You’re not buying the salesperson.”

These “defence mechanisms,” Cialdini said, help “ensure that we make more objective choices.”

NOW WATCH: This simple work hack will make you more productive

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.