Influence, in bytes

The idea

We rely on shortcuts to cope with a complex world: if it's expensive, it must be good; if an expert says it, it must be true. They usually work, which is exactly why they can be exploited.

In practice

A shop that raises prices on some items can see them sell better, because higher prices signal quality.

The idea

How we judge something depends on what we saw just before. A second option seems cheaper, larger or better after a more extreme first one.

In practice

Salespeople sell the expensive suit first; the sweater that follows then seems a small extra cost.

The idea

We feel obliged to repay what others give us, even small, unrequested gifts. It is one of the strongest social rules in every culture.

In practice

Free samples, small gifts or a favour from a salesperson make people more likely to buy.

The idea

If someone turns down a large request, then agrees to a smaller one, it feels like a concession, and we feel obliged to concede in return.

In practice

Cialdini was asked to buy circus tickets, refused, then bought chocolate bars he didn't want when the request shrank.

The idea

Once we take a stand, we feel pressure to act consistently with it. Small commitments can lead to much larger ones.

The evidence

In one study, homeowners who first agreed to display a small safe-driving sign were far more likely to accept a large, ugly billboard later.

The idea

Commitments that are active, public and effortful stick hardest. Writing something down makes us more likely to follow through.

In practice

Sales teams that have customers fill in the order form themselves see fewer cancellations.

The idea

An attractive offer gets a commitment, then the terms change. People often stick with the decision, having built new reasons to justify it.

In practice

A car dealer offers a great price, then an “error” adds extra costs after you have mentally bought the car.

The idea

We decide what is right by looking at what others do, especially when we are uncertain.

In practice

Canned laughter makes people laugh more at shows, even though they know it's fake.

The idea

In an emergency with many onlookers, people often wait for others to act, and each assumes someone else will help.

In practice

Bystanders may walk past someone who has collapsed, assuming it's already being handled.

The idea

Social proof is strongest when the people we see are like us.

In practice

Testimonials from “people like you”, in your industry or city, persuade more than celebrity endorsements.

The idea

Liking is a powerful lever. We tend to agree with people who are attractive, similar to us, who compliment us, and with whom we cooperate.

In practice

Home-selling parties hosted by a friend sell more because buyers are saying yes to their friend.

Example

At Tupperware parties, guests buy as much from liking and obligation to the host, a friend, as from the products themselves.

The idea

We like people who seem like us in background, interests or style, and we warm to praise, even when we suspect flattery.

In practice

A salesperson who mentions they're from your hometown can feel instantly more trustworthy.

The idea

We transfer feelings about one thing to the people or products linked with it, good or bad.

In practice

Brands pay sports stars and celebrities so their positive image rubs off on the product.

The idea

We are trained to follow legitimate authority, sometimes too far. Stanley Milgram's experiments showed ordinary people obeying instructions they found disturbing.

In practice

People often follow a confident instruction from someone in a uniform without questioning it.

The idea

Titles, clothing and trappings can trigger obedience even without real expertise.

In practice

Advertisements use actors in lab coats to recommend health products.

The idea

Things seem more valuable when they're rare or becoming less available. We hate losing options.

In practice

“Only three left in stock” and countdown timers push online shoppers to buy quickly.

The idea

Items become even more desirable when they have only recently become scarce, or when others compete for them.

The evidence

In a cookie study, people rated cookies higher when the jar had few left, and higher still when it had just been reduced from many.

The idea

When our freedom to choose is threatened, we want the restricted option more.

In practice

Banning a book or product can make people more eager to get it.

The idea

Cialdini's seventh principle, added in the 2021 expanded edition: we are most influenced by those we see as “one of us”, through family, place or shared identity.

In practice

People favour requests from fellow alumni, colleagues or people from their home town.

The idea

Doing things together, such as singing, working or celebrating, creates a sense of being one group, which increases cooperation.

In practice

Teams that go through a demanding project together often stay loyal to each other for years.

The idea

Cialdini distinguishes between using real features of a situation to persuade, which is fair, and faking them, which is manipulation and backfires over time.

In practice

Highlighting genuine customer reviews is persuasive; inventing them destroys trust.

The idea

The best protection is noticing when a principle is being triggered artificially, then pausing to think.

In practice

Recognising “this is reciprocity” when handed a free gift gives you room to decide freely.