• Joumana Elomar

The Psychology of Persuasion: 6 Principles You Need To Know

Influence is power. Perhaps the most powerful type of influence is one we're unaware of. From the science of persuasion, we know certain psychological principles pressure us to say yes. While most of us are hyperaware of the strategies people use, sometimes things slip by. So what are the core principles? And what can we watch out for?

Six Principles Of Persuasion

In 1984, psychologist Robert Cialdini published 'Influence: The Psychology Of Persuasion', distilling over 30 years of evidence-based research on what motivates people to change behaviour. His main message? Making decisions takes a lot of mental resources, so we tend to lean on mental shortcuts (heuristics) to decide what to do.

Within this, he pulled out six principles for persuasion:

To dive a little deeper, here's what each means:

  • Reciprocity: We tend to give what we receive. You might notice that if someone does something for you, you may feel compelled to give back e.g. If a stranger smiles at you, you smile back. If a co-worker helps you on a task, you tend to be more willing to help back. The core idea is that the person who acts first can influence the behaviour of the other.

  • Social Proof: We tend to check what people similar to us are doing. By surfacing social proof, people are more inclined to follow. In one study, a restaurant found that by flagging popular dishes with stars, they became 13%-20% more popular than before.

  • Authority: We tend to say yes to experts. People who are perceived as credible sources of information have more standing. Interestingly, sometimes people assume we know their expertise or choose not to surface it impacting the way we view them.

  • Consistency: We tend to act consistently with our past commitments. For example, in Cialdini's work he mentions a restaurant owner who used this principle to reduce the number of no-shows. Previously, the receptionist would say "...If you have to change or cancel your reservation, please call." which resulted in 30% of no-shows. By changing it to "Will you please call if you have to change or cancel your reservation?", and waiting for people to say yes, no-shows dropped to 10%.

  • Liking: We tend to say yes to people we like. No surprises here! If we like someone or have genuine similarities with them, it builds rapport and increases our likelihood to say yes to their requests.

  • Scarcity: We tend to value what's in short supply. Research has well established that if something is perceived as scarce, we're more likely to act on it e.g. the "last one" or a "special deal". This is a common tactic in marketing where companies trigger our fear of missing out e.g. "Today, 45% off!" or "Sale until midnight" to push us to purchase more quickly.

And those are the six principles of persuasion! For the sake of clarity, they've been split into separate principles but Cialdini notes that these are much more powerful when used together. Interestingly, he also emphasises that these principles are less effective if they're abused or if we can spot when people are using them disingenuously. Or in his own words:

Not only is it ethically wrong to trick or trap others into assent, it’s ill-advised in practical terms. Dishonest or high-pressure tactics work only in the short run, if at all. Their long-term effects are malignant, especially within an organization, which can’t function properly without a bedrock level of trust and cooperation.

Wrapping up

Persuasion is powerful. The principles that underpin persuasion target our tendency to rely on heuristics (mental shortcuts). Whenever we make decisions, we need to be wary and slow down to make wiser decisions. As psychiatrist and author Gordon Livingston once said "only bad things happen quickly".


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