Influence: The Unseen Key Behind Powerful Persuasion
One day Robert Cialdini was in his university dorm, when he answered the door to another resident who was selling subscriptions to Sports Illustrated magazine.
“I was a starving student; I didn’t have a lot of discretionary income,” Cialdini recalls.
He told Cialdini that he would be missing out on a unique sale that would only last for that weekend.
“I thought, ‘You spent your money, and it wasn’t because of the merits of the thing – it was the way he presented it,'” Cialdini recalls.
Cialdini’s curiosity would lead him to write Influence: The Psychology of Persuasion, published in 1984.
Melding academic research on behavioural science with opposite case studies and personal experience, it arguably created the mould for “Smart thinking” authors such as Charles Duhigg, Adam Grant or James Clear.
After numerous updated editions, his book has now sold more than seven million copies, according to his publishers.
On the book’s 40th anniversary, I sat down with Cialdini in a London hotel to discuss its conception and impact, and the ways that the psychology of persuasion has evolved in the decades since its first publication – and its implications for today’s fractured societies.
As part of his research, Cialdini had decided to spend time studying people he defined as “Compliance professionals” – those in sales, marketing, recruitment and fundraising whose livelihoods depend on changing others‘ opinions.
I ask Cialdini which experience stands out, and he describes accompanying a stellar salesperson offering heat-triggered fire-alarms on door-to-door visits.
On their trips, Cialdini’s mentor always brought a big book of sales material detailing the different products – but repeatedly left it in the car.
As the homeowners performed a safety test of their house, he would ask if he could borrow their keys so he could go to collect it and let himself back into the house.
“He said, ‘Bob, who do you trust? You trust people who you will allow in and out of your house by themselves, and I wanted to be associated with that,'” Cialdini recalls.
After three years of comparing these experiences with the published research, he identified six overarching principles that appeared to underline any persuasive campaign.
The student selling Sports Illustrated perfectly illustrates three of these principles.
He offered social proof – evidence that other people like us are taking the same action by describing how many of Cialdini’s dormmates had taken up the offer.
“It shows that the action is valid, and demonstrates that it’s feasible to undertake,” says Cialdini.
We are more likely to download a song if we have been told it’s popular with other listeners, and people were more likely to wear a mask during the Covid-19 pandemic if they saw others do the same.
The liking principle – that we are more likely to agree to someone’s suggestions or demands if we warm to them personally – may seem self-evident, but a quick look at the invective of political debate suggests that many fail to put it into practice when trying to convince others of their opinions.
In the first edition of his book, Cialdini pointed to studies of “Tupperware parties” – a business model in which a member of a community could earn a commission by hosting a gathering and then selling the kitchen containers.
The research showed that the greater people’s social connection to the host, the more likely they were to buy a product – irrespective of its quality or features.
Reciprocation reflects the adage that “You scratch my back, I’ll scratch yours“, but in Influence, Cialdini showed that very small favours can pay great dividends – as shown by the famous “Coca Cola” experiment, in which the psychologist Dennis Regan invited participants into the laboratory.
In some trials, he came back with two bottles of Coca Cola – one for himself and one for the participant; in others, he returned with nothing.
After the experiment was allegedly over, Joe asked the participant whether they’d like to buy raffle tickets he was selling, and his prior behaviour had a large impact on their decisions.
If Joe had shown that small act of generosity in purchasing the extra Coca Cola, they bought considerably more tickets.
Cialdini phrases it like this: “Once we make a choice or take a stand, we encounter personal and interpersonal pressure to think and behave consistently with that commitment.” Simply asking someone to say whether they are going to vote can increase the chances that they will cast a ballot since a failure to do so would seem inconsistent and cause an uncomfortable feeling of “Cognitive dissonance“.
In the updated editions of Influence, Cialdini has added a seventh principle – unity, the fact that people are “Inclined to say yes to someone they consider one of them“.
“I always saw unity as an amplifier: if you had unity, then scarcity or social proof were going to be more powerful. But then I started to see that it had a force that was independent of any of the others.”
“And I immediately became more favourable to their music, and wanted them to succeed in the future.”
I ask Cialdini if his studies of persuasion have armed him against manipulation from canny salesman.
“When it’s a trick, then I’m equipped to say no.” If the information is honest and well-sourced “I’m more likely to say yes, since these principles can guide us correctly.”
He points out that it is perfectly rational to care if a product has been popular with other people, for instance – since that increases the chance it will have personal appeal.
In the decades following Influence’s publication, Cialdini’s advice has been highly valued by business leaders and politicians alike.
They described the total number of people who had contributed.
I ask Cialdini how we might promote a greater sense of unity in today’s polarised world.
You might invite a colleague to dinner, for instance – even if their worldview clashes with your own.
You might expect fireworks to result from those conversations, but the psychological research suggests that we are often better at bonding with our political “Enemies” than we believe.
Cialdini certainly makes it sound easy and achievable to apply these psychological principles in our day-to-day lives; I leave the interview feeling that I have a much better handle on the ways that I might improve my communication – and the strategies that others might employ to sway my thinking.
Perhaps it’s his own powers of influence, but he has convinced me that the psychology of persuasion is even more relevant today than it was in 1984.