373: Dr. Robert Cialdini On Using Influence And Persuasion To Grow An Ecommerce Brand

Podcast: Download (Duration: 1:05:42 — 75.5MB)

The seven Cialdini principles of persuasion are reciprocation, liking, social proof, authority, scarcity, commitment and consistency, and unity. Unity is the newest, added in the 2021 edition of Influence, and it says people say yes to communicators who convince them they share an identity rather than merely a similarity.

In this episode I sat down with Dr. Robert Cialdini, known globally as the godfather of influence. His book Influence: The Psychology of Persuasion is the single book that changed how I run both of my businesses, and the new edition adds 220 pages.

Below is the full tour: all seven principles, the specific research behind each one, and how to apply them to an ecommerce store without fabricating anything.

Key takeaways

• Unity is the seventh principle. “One of us” is a different level of influence than “like us.”
• Give first, and make the gift relevant. Free yogurt beat a free keychain 24% to 12% in a restaurant study.
• Say “more and more,” not “more.” Three data points make a trend, which creates future social proof.
• Ask for advice, never feedback or opinions. Advice puts people beside you, opinions make them critics.
• Put testimonials first, not in the body. They infuse everything that follows.
• Mention a weakness, then say “but.” Place your strongest argument immediately after.
• Ratings above 4.7 hurt conversions. The sweet spot is 4.2 to 4.7.
• Limited quantity beats limited time. Quantity implies competition and forces action.

Why the new edition of Influence is essentially a new book

The 2021 edition adds 220 pages for three reasons: a decade of new persuasion research, the migration of these principles onto internet platforms, and the addition of a seventh principle.

Dr. Cialdini’s framing is that the new material amounts to appending another book rather than revising the existing one.

The internet section exists because the twelve years since the previous edition changed where persuasion happens. Showing how the principles operate on new platforms was a specific goal.

Principle 1: Reciprocation

People want to give back to those who have given to them first, which means the influence attempt should come after the gift rather than before it.

This rule holds in every human culture, so it applies regardless of where your customers were raised. We are trained from childhood not to take without giving in return.

The implication inverts the standard business model. Instead of promising value in exchange for a purchase, you go first, and recipients feel obligated to reciprocate.

Online, the cheapest version is information: a white paper, the top three mistakes to avoid in your category, the five most effective things to say in a difficult conversation.

This is the principle My Wife Quit Her Job is built on. I give away the genuinely good material for free, and a subset of readers will buy anything I sell.

Why relevant gifts outperform generic ones

Segmenting your gift to the recipient’s actual situation roughly doubles the effect, which a fast food study demonstrates cleanly.

Three groups of customers entered a restaurant:

• Greeted warmly by the manager, with no gift.
• Given a nice keychain, and bought 12% more food.
• Given a small cup of yogurt, and bought 24% more food.

Any economist would predict the opposite for the yogurt group, since free food should reduce hunger and therefore spending. It doubled the effect instead.

The reason is relevance. You go to a restaurant because you are hungry, so free food demonstrates that someone understood your situation and tried to meet it.

The ecommerce version is segmenting your free content by customer type. Hotel sites do this well: the best options for a romantic weekend, for a business stay, for a family vacation.

Why gifts must come before the purchase

The same gift produces dramatically different results depending on whether it arrives at the beginning or the end of the transaction.

McDonald’s locations in Brazil and Colombia gave every family a balloon per child. Half received it on the way out as a thank you. Half received it on arrival.

The families given balloons on arrival bought 25% more food.

The detail Dr. Cialdini loves is inside that number: coffee orders rose 20%, and children do not order coffee.

The parents did, because doing something for someone’s child registers as a personal favor to the parent.

Principle 2: Liking

People say yes to those they like, and two specific moves increase liking measurably.

Find genuine similarities. We like people who are like us, so locating real points of overlap builds rapport.

Give genuine compliments. We like people who like us and say so.

The online application is a welcoming letter. Research shows a welcome message significantly increases liking and purchases, functioning the way greeting a visitor at your door does.

My own version at Bumblebee Linens is a personalized thank you email after a first purchase, saying we are a small business and will do whatever it takes to make them happy. It is automated and it generates enormous numbers of replies.

Dr. Cialdini’s improvement on it: move that message to everyone who arrives on the site before they buy, which increases conversion significantly.

The About page is the other underused surface. Most list professional backgrounds and photos, and they should also include personal details so visitors can find connections to themselves.

Principle 3: Social proof

Uncertain people look outward rather than inward, and specifically toward people like themselves.

Others effectively beta test the decision for them, which is what gets someone off the fence and stops the search for more information.

The simplest application is pointing at what is already most popular. Dr. Cialdini’s position is that you would be a fool not to.

The evidence is a McDonald’s study led by his colleague Steve J. Martin. Staff added one line at the end of each order: would you like to try a McFlurry, it’s our most popular dessert.

McFlurry orders rose 45%.

This works for a most popular product, feature, or payment plan, and it costs nothing because you are pointing at a fact rather than manufacturing one.

How to use social proof when you have few customers

Show a trend rather than a total, because people project trends forward into future social proof.

This is the finding from Dr. Cialdini’s team working with researchers at Stanford. A startup without market share can still demonstrate movement in its direction, even from a minority position.

The wording matters precisely. “More people are buying this” gives two data points. “More and more people are buying this” gives three, and three data points make a trend.

The same construction works with any dimension: better and better, greater and greater. Actual numbers work better still.

For testimonials, two rules apply: place them at the top of your messaging so they infuse everything that follows, and choose people your market can see as comparable to themselves.

Principle 4: Authority

People defer to demonstrated credentials, experience, and know-how, which reduces their uncertainty the same way social proof does.

Borrowing authority works when you lack your own. Quoting legitimate outside experts about your idea or category transfers some of their credibility.

Placement follows the same rule as testimonials. Expert endorsements belong before your argument rather than buried inside it, so everything that comes after arrives already legitimized.

Publishing content builds authority on its own. A white paper, an article, or an interview where your material is embedded signals to readers that they can stop searching for other sources.

The counterintuitive way to strengthen authority

Mention a weakness in your case, then say “but,” and place your strongest argument immediately after.

The mechanism is credibility. Acknowledging a drawback proves you know both the pros and the cons, which makes you a trustworthy source rather than a salesperson.

Most people bury weaknesses at the end or omit them. Dr. Cialdini’s advice is the opposite: the position right after a stated weakness is where your best argument belongs, because it will be believed more deeply.

The examples he gives: this may take a little longer, this may cost a little more, we do not have much market share yet. Then “but,” then the strength that erases it.

The same logic explains review ratings. Research shows the highest-converting star rating is between 4.2 and 4.7. Below 4.2 buyers doubt the product, and above 4.7 they suspect the reviews are purchased or filtered.

How to respond to a negative review

Respond by invoking the social proof that genuinely exists, then acknowledge the individual experience and commit to fixing it.

Dr. Cialdini’s suggested wording: thank you for your response, we are so happy that the great majority of people have not had your experience, but we certainly regret that you did and we will take steps to make sure it never happens again.

That structure does two things at once. It identifies the reviewer as an outlier through true social proof, and it demonstrates responsiveness to everyone reading.

Principle 5: Scarcity

Scarcity produced the largest effect of all the principles in a study of online marketing, outperforming every other lever on conversions.

The specific forms that work: a limited supply at a given price, with a given feature, or with a given bonus.

Limited quantity beats limited time, and the reason is competition. A limited number means someone else may take it, which forces immediate action. A limited time lets people wait until the deadline approaches, which spurs nothing now.

My own store confirms this. When a product drops below ten units and we display the remaining count, that product sells out noticeably faster.

The honesty constraint is absolute. If the scarcity is not real, do not claim it. What you can always do is create genuine scarcity through a bonus available to the first hundred buyers.

Principle 6: Commitment and consistency

People act consistently with what they have already committed to, so small early steps make larger later steps more likely.

The button copy application is specific. A button reading “Next” or “Yes” captures no commitment. A button reading “Yes, I want to go on to the next level” does, because the visitor has affirmed something.

The form-length application follows the same logic. Reducing the number of fields on the first page significantly increases completion rates, because once someone clears the first page easily they are far more willing to finish.

This is why one-question-per-page surveys get completed and long single-page forms do not.

Principle 7: Unity

Unity means convincing people you share an identity rather than merely resembling them, which is a categorically different level of influence.

The distinction Dr. Cialdini draws: getting someone to say “Steve is like us” activates liking. Getting them to say “Steve is one of us” is something else entirely.

Inside the boundaries of “we,” people believe you more, cooperate more, are persuaded more, comply with requests more, and trust you more.

His own example: learning that Lil Wayne and Justin Timberlake are avid Packers fans immediately made him think better of their music and want them to succeed. He grew up in Wisconsin.

The practical method is research before contact. LinkedIn and Facebook tell you a great deal, and when you find a real connection you go there.

You are a runner, I am a runner. You are an only child, I am an only child.

Going to a non-connection or a rivalry does not help, though genuine negative rivalries are far rarer than available connections.

The persuasion strategy that works on a spouse

Invoking the relationship itself outperforms both coercion and logic, and it is the only approach that produced change in a study of romantic couples.

Researchers in Texas brought couples together for at least two years, had them name an unresolved disagreement, and assigned one partner to persuade the other. Three types emerged.

The coercive persuader threatened consequences. This failed and pushed the partner further away.

The rational persuader argued their position was more reasonable. This produced laughter and no movement at all.

The unity persuader said some version of: we have been together for two years as a couple, I would really appreciate it if you moved in my direction on this. This was the only approach that worked.

The mechanism is that they refused the frame. The researchers primed them to think about a difference, and these people brought togetherness to consciousness instead, which activates every “we” effect at once.

Simply using the pronouns we, our, and us produced the same result for the same reason.

Reciprocation then closes the loop. When the partner moved toward the persuader, the persuader moved back, and they met in the middle.

Dr. Cialdini used the identical approach on a notoriously difficult colleague who had already refused to send him data. Saying “we have been together in the psych department now for 12 years, I really appreciate this” got him the data that afternoon.

Why you should ask for advice instead of feedback

Asking for advice puts someone beside you as a partner, while asking for an opinion or feedback puts them across the line from you as a critic.

The research: people online received a business plan for a fast food restaurant focused on healthy food. Those asked for their advice rated it significantly more positively than those asked for their opinion.

The reason researchers found was togetherness. Providing advice made them feel aligned with the author.

This applies directly to co-creation, which has been a major success in marketing over the past decade. Inviting existing customers to shape the next version of your product produces greater loyalty and satisfaction before the product even ships, because they now feel like part of you.

The word choice is the whole game. Ask what advice they have, not what their opinion is.

The ethical constraint on all seven principles

Point to these principles only where they genuinely exist in your situation, which is the entire line between influence and manipulation.

Dr. Cialdini’s rule: if you have genuine scarcity, use it. Genuine social proof, use it. Genuine authority, genuine unity, use them.

He explicitly declines to recommend the famous study where an actor dressed as a doctor sold more, on the grounds that it is not honest.

The upside of the constraint is that nothing here requires fabrication. Every effect described costs nothing and works by directing attention to something already true.

Frequently asked questions

What are the 7 principles of persuasion?

Reciprocation, liking, social proof, authority, scarcity, commitment and consistency, and unity. Unity is the newest, added in the 2021 edition of Influence, and it operates on shared identity rather than mere similarity.

What is the unity principle?

People say yes to communicators who convince them they share an identity, meaning the kind of group described with the pronoun “we.” Getting someone to think “one of us” rather than “like us” increases belief, cooperation, persuasion, compliance, and trust simultaneously.

Should you give something away before asking for a sale?

Yes, and make it relevant to the recipient’s actual situation. In a restaurant study, a free keychain increased purchases 12% and a small cup of free yogurt increased them 24%, because food addresses why someone entered a restaurant.

How do you use social proof with few customers?

Show a trend rather than a total, since people project trends into the future. Say “more and more people are choosing this,” which gives three data points and constitutes a trend, rather than “more people,” which gives only two.

Should you mention weaknesses in your marketing?

Yes. Naming a drawback, saying “but,” and following immediately with your strongest argument makes you appear credible and trustworthy, which causes people to believe everything you say afterward more deeply.

What star rating converts best?

Between 4.2 and 4.7. Below 4.2 shoppers doubt the product, and above 4.7 they suspect the reviews were purchased or filtered. Perfect ratings undermine trust rather than building it.

Is limited quantity or limited time more effective?

Limited quantity, because it implies competition and forces immediate action. A limited time offer lets people postpone until the deadline nears, which produces no urgency now.

Should you ask customers for feedback or advice?

Advice. Asking for an opinion or feedback makes someone a critic standing across from you, while asking for advice makes them a partner standing beside you. The same business plan scored significantly higher when reviewers were asked for advice.