In this series, we’ll be talking about some basic principles of persuasion in marketing. But don’t let the word ‘basic’ fool you, because these principles run deep in our bones and their influence is hiding in everyday plain sight.

Throughout this series, we’ll be relying heavily upon the work of an expert we’ve mentioned before: Dr. Robert Cialdini, known for his expertise on persuasion (and influence more generally).


But before we go any further… how exactly is reciprocity defined?

Robert Cialdini

Fans of Chicago will know the real answer: by Queen Latifah, that’s f**king how.

Ahem. She’s the warden of a women’s prison. She begins this number by singing:

Ask any of the chickies in my pen / They’ll tell you I’m the biggest mother… hen
I love them all and all of them love me
Because the system works / The system called… reciprocity 🎵

(She’s corrupt. In her case, it’s about trading privileges for profit.)

Anyways. Most people think reciprocity means ‘tit for tat’ or ‘fair trade’ or something to that effect… but that’s not quite it. Reciprocity refers to the principle of fair trade, that people naturally understand the need for both parties to benefit from exchanges. Trade of all kinds, including conversation, falls apart if people can’t trust one another in this fundamental way—if one or both parties feel that things are one-sided. (You have examples too?!)

You have to (temporarily) adopt a cynical view of the world, but ask yourself: what do you trade, giving and getting, in each relationship you have? We’ll bet you’re happiest in the relationships where you’re satisfied with ‘the trade,’ or where you feel that the exchange is fair (perhaps even favorable to you).

Three things digital businesses need to understand here:

You MUST be prepared to give value up front. A lot of times, when people are chapped by this idea, it’s because it forces them to be deferential. In most face-to-face trades, it would be disadvantageous, if not downright insulting, to be expected to give something just to enter the discussion.

Here’s what you have to remember: money is like blood. People are naturally selective about where they spill either one, and they tend to distrust people whom they sense want either one.

In this analogy, businesses are like vampires—but this analogy is also set in the Twilight universe, where that’s kinda okay. And businesses, to do their jobs, have to be Edward Cullen and make people feel Bella about it.

To charm people into spilling their money with you, you have to give them something in advance… something they want and like, even if it’s small.

People tend to be happiest with the trades that solve problems. Think about the last time you (in some way) paid to make a problem go away. Holy crap, doesn’t that feel good just to think about?

People HATE problems (duh). More specifically, they hate solving them alone, from scratch. Trading is super quick and easy by comparison, right?

This isn’t just a useful angle for selling things. More basically, it is the expectation customers will hold over time. Does this thing (still) help me?

This is where quality service makes a huge difference. When you think about it, Customer Service is a common frustration because we often don’t expect to get real help—and we don’t expect real help because we think (or know) that the real trade has already happened.

They’ve already got your money. Why bother asking for anything, right?

While this low bar of expectation will help explain some of the nastier tickets, it’ll also make it easier to blow people’s minds with happiness and joy. Translation: a few resources and some TLC will buy lifelong customers—and this happens because it makes them feel safe trading with you, like you won’t just leave them out to dry once you’ve taken their money.

Commitment and Consistency

For this whole series, much of our job is defining key terms more clearly. This is because the same thing that makes psychology easier to understand (versus, say, organic chemistry) also makes it easier to confuse and abuse. The devil is in the details, and these details are definitions.

First, let’s zoom out a bit and define Cialdini’s two biggest words: Influence and Persuasion. Influence is the general ability to affect other people’s beliefs and behavior. Persuasion is influence exerted through reasoning, or the ability to influence others by communicating with them.

⚠️ Critical Distinction: Persuasion requires effort, but it does NOT require force. When it requires force or threats, it’s called coercion and we’re not doing that here.

Notice that persuasion is communicating with people, not communicating to people. This is part of what makes persuasion hard; we know everything about what WE want but way less about what THEY want (never mind how to bridge the two). It is therefore critically important, when persuading people, to take and use the things they say.

This is where commitment and consistency comes into play.

The basic idea here is that everyone wants to be true to their convictions. If you think and say “I am X” or “I want Y,” you’ll naturally want your other thoughts and actions to be consistent with X and Y. All of us want to avoid cognitive dissonance (that queasy feeling when our own thoughts and feelings clash), but especially when we’re thinking about ourselves.

We feel this urge to “commit and be consistent” even when others aren’t watching, but the feeling is stronger when others are watching—and that’s what makes it so useful for persuading people.

This principle allows you to assume ONE thing the other person wants, beneath everything else y’all discuss, and that is: They want to be consistent with the beliefs and wishes they’ve already stated. To make persuasive use of this principle, you start with a smaller agreement and then take as many logical steps as you need to reach the bigger agreement.

A couple of examples:

🚙 When you’re evaluating a car with a salesperson, they’ll usually start with low-stakes questions like “Would you prefer something with cloth seats or leather?” Doesn’t feel like a commitment, but that’s the point: after a dozen little questions (whose collective answers give you a clear picture), you’ll feel weirder walking away from the lot.

⚔️ When the Chinese took American POWs in the Korean War, they didn’t start by asking them to renounce the United States. They started by asking if it was possible that the U.S. government had ever made a mistake—which is, obviously, much easier to agree with—and then worked up to renunciation from there.

All of Marketing and Sales is essentially “persuading people to buy.” Don’t start with what you think they want (and then try to cram an offer down their throats). Start with what they say they want, then work towards the conclusion that Your Offer and Their Wants are actually the same thing.

It all starts with one little agreement—often littler than you might think—and it proceeds in smaller steps than you might like. This takes patience, so just remember: you catch more flies with honey than you do with vinegar.

Social Proof

The concept of “social proof” doesn’t need much introduction for marketers. This is one of those phrases that managed to escape its original context (Robert Cialdini and principles of persuasion) and enter a wider vernacular.

Fortunately, the core meaning has remained intact despite the phrase’s deeper circulation. Social proof is just the idea that things are easier to buy, literally or figuratively, if you’ve seen other people approve of them first.

There is, of course, more to it. Starting at the lowest level…

There’s some monkey-brain overlap between social proof and the bandwagon effect. To borrow a Tommy Lee Jones phrase: a person is smart, but people are dumb panicky animals. We hop on bandwagons and watch closely for social proof simply because we’re all social animals (even the introverts) and we’re all terrified of separation from our packs.

More generally, you can explain both social proof and the bandwagon effect with three words: uncertainty is uncomfortable. We look to others for the answers because we want to do the right things—or at least, we want to avoid doing the wrong things alone.

That’s all basic monkey stuff. Now we add a couple of layers…

Fears aside, we tend to (want to) trust our people. Social proof can absolutely come from strangers—in fact, that’s most of what’s out in the world, by volume—and sometimes, the opinion you really want is the anonymous one. Having said that, social proof will usually have a stronger persuasive influence the more you identify with the person providing it.

Past a certain point, social proof isn’t just supporting you “in case” you want to do something; it’s actually giving you a reason to do that something. Following someone else’s recommendation bonds you to them and builds trust; it puts you in some kind of boat with them. If nothing else, it guarantees that you’ll never be wrong by yourself; if it winds up being a bad idea, at least you’ll have a buddy down there in the hole with you. Either way…

Social proof provides valuable information. One reason for the constant, gentle hum of anxiety in our brains is that we don’t know everything—all things considered, we barely know anything—and yet, cruelly, we’re aware of this ignorance anytime we think about it. Helpfully, other people happen to be good sources of information whether you care about them or not.

Think about the last time you read more than 10 reviews before buying something. We’ll bet that you got two types of impressions:

Thoughts 🤔 Reviewers tell you what they can see and feel, what they can perceive and describe. Some reviews answer the obscure questions in your mind; others give tips and suggestions and ideas. All of this information is concrete and reasonably specific.

Feelings 🎭 The nice thing about reading reviews from below the Intellectual Fiftieth Percentile is that it’s easier to see the emotional vapor trails. Most smart people are boring to read because they tuck everything in with prOpeR enGlish and hide how they feel beneath polite and polished phrases. Not so with the lower deck. If they love or hate something, you will feel it right away. There will be many exclamation points and capital letters and passionate misspellings.

This information is less useful by itself, but it’s super useful in concert with the information from Thoughts above. This is how you figure out (in seconds) whether it’s the product that sucks or the person reviewing it.

Final word for marketers: testimonials. Seriously, if you read only one word in this article, read that word again. Testimonials. There 👏is 👏no 👏excuse if you don’t have social proof, because testimonials are a thing and they have been for a long time. Mmmkay?


The concept of authority is paradoxical because, while its outer details are very “adult,” its psychological roots are deeper than anyone can remember.

Let’s start at the beginning.

When we’re born, we’re completely helpless. We attach to our parents in a number of ways, for a number of survival-related reasons. Our parents are ‘authorities’ not only because they provide for our needs, but because we quickly understand that adults live in a different world above and apart from the kids—and only the adults understand the workings of both worlds.

While this might seem like a needlessly primordial comparison, the difference between parents and children is the deep beating heart of authority, all forms of it. First of all, literally everyone starts out as someone’s helpless infant and literally everyone gets to adulthood the long way (by growing up). Secondly, the Latin root of the word ‘authority’ means ‘originator,’ and this reflects a neat dual meaning: a person who is a source of knowledge, but also, maybe, a person from whom YOU originate.

As we grow up, this parental authority is gradually transplanted to other sorts of people: extended relatives, teachers, police, and so on. At a large scale, this shared sense of authority is a “cultural glue” that helps societies function smoothly. It is, literally, the natural order for children to follow the leadership of their parents’ authority—and as we age, this authority spreads out to the more general understanding that we should trust the people who came before us (and who know way more than us) in their area of expertise.

The point here, for Cialdini’s purposes, is that we don’t even have to think to be persuaded by authority. If it presents itself in the right ways, we won’t even realize it’s happening. For example: studies have shown that patients are likelier to comply in physical therapy if their therapists display their medical diplomas somewhere visible on the wall.

Cialdini defined three symbols of authority, which visibly mark that authority for anyone to see. Try to keep an open mind and interpret these loosely.

Titles. In one study, participants estimated a person’s height based on the description provided to them by the researcher. Participants consistently imagined that people with more prestigious professional titles were physically taller (and the fact that this makes no rational f**king sense should underscore how little we need to think for authority to work its magic).

Clothing. Much has been made of the white-coat effect with doctors (or clever con men pretending to be doctors a la Catch Me If You Can). In general, people feel that a uniform gives a clear indication of what a person does AND solidifies that they “live in” that expertise.

Trappings. Another term here could be “status symbols,” because this one varies a lot more depending upon the context and type of status you’re seeking. The old-school examples are flashy things like cars and jewelry—but consider that, in the digital age, “trappings” can totally include stuff like having 50 big companies’ logos on your homepage to associate yourself with them.


Robert Cialdini’s fifth principle of persuasion is a bit elusive, mostly because he named it with one of the most generic words in English: liking. We’re not gonna insult your intelligence by defining the word for you, but we will clarify that he’s referring specifically to the persuasive power of liking other people.

Skimmers be warned: the devil’s in the details here, and this is one time when you’ll need to slow down enough to re-examine the obvious.

We’ll gently crack the shell here with three examples:

Good Cop/Bad Cop works specifically because you like the Good Cop. If you wanna say “but the Bad Cop plays a role too,” you are correct… but let’s be specific about who’s doing what. First, the Bad Cop’s main job is to multiply the Good Cop’s likability—and then it’s the Good Cop, and not the Bad Cop, who wields the real persuasive power to get results.

Sex sells because people like sex. There should be more to this, but there really isn’t.

Celebrity endorsements are so common because viewers like celebrities—and because, economically speaking, agreements are likelier to repeat the more frequently they end as win-wins (see above).

So when it comes to persuading people, it really matters that they’re able to like you somehow. Cialdini names these as the five main factors in liking:

Physical Attractiveness ✨ This is not just because people like having sex with people they find attractive. It’s also because human beings tend to assume that outwardly attractive people have attractive qualities on the inside too; this is called ‘the halo effect.’

Similarity 👥 We automatically like people more the more they have in common with us. This is why, in the protracted periods of small talk during car shopping, the salesperson will desperately cling to anything they think connects you together.

Compliments 🥰 As much as we can pretend otherwise, we all like compliments. They’re a huge deal to our social-animal monkey brains because they are direct, explicit external validation from our fellow social monkeys. As a species, we like compliments so much that we barely question them for any reason, ever.

Contact and Cooperation 🤝 We have a greater chance of liking people the more familiar we become with them AND the more we work together towards some common goal. The phrase you’ve probably heard is “familiarity breeds liking,” and it’s true.

Conditioning and Association 🐶 Your opinion of someone (and thus, your level of openness to their persuasion) can turn on a dime, in either direction, when you find out where they rub shoulders. Maybe you trust somebody overnight once you find out they’re close with the right person; maybe you like someone until you find out they’re chummy with that one schmuck.

One last thing before we move on. While it is true (and painfully obvious) that it’s easier to sell things when people like you, you don’t have to BE everything that’s likable about your business; in other words, you don’t have to be perfect and exhibit all of the above qualities yourself. In just about every factor above (especially the first one), you can borrow someone else’s likability as long as it winds up pointing back to you.


Robert Cialdini’s sixth and final principle of persuasion is scarcity, a concept with which everyone is familiar. In a sentence: resources are naturally limited, so we have to make decisions about what we get and what we don’t. At an individual level, we call this choice; at a society-wide level, we call this economics.

Cialdini is, of course, more concerned with individual decisions. And he’s quick to point out why scarcity works for persuasion. In his own words: The scarcity principle trades on our weakness for shortcuts.

More specifically, he’s referring to our weakness for cognitive shortcuts, for cutting corners in conscious reasoning and decision-making. This isn’t an external hack, like getting someone’s leg to jump by tapping their kneecap; this just makes use of what we know from the inside, which is that our brains breathe a sigh of relief whenever complex situations are reduced down to simple choices for us.

Let’s say you have your eye on a pair of basketball shoes. You definitely like them, but you’re not sure if you want to buy them. This is a complex decision because all of your options are equally open; you could buy the shoes OR buy a different pair of shoes OR buy something else entirely. You probably won’t buy the shoes today because you can always buy them later—and why burn your spending money (and chance to choose) if you’re not sure you want them?

Now imagine that they’re not just any basketball shoes… they’re limited-edition Jordans. This is a classic scarcity play, and its purpose is to greatly narrow the decision for interested buyers. Instead of silently offering the shoes as one of infinite options for spending your money, it demands a binary choice: take me or leave me, now or never.

This creates two feelings at once: relief from having a simpler choice, but also a bit of threat from having an ultimatum. (“Oh, okay, umm, s**t. Lemme think a second.”) After taking a second to place the feeling in your own mind, notice two things about what’s happening here:

The ultimatum is a ‘threat’ only in the vague, impersonal sense of the word. Most of the time, people don’t take scarcity personally. We all know that scarcity is a natural reality; we even know that some scarcity is manufactured, though we argue with it less the less commoditized the goods (limited-edition Jordans have value that can’t be replaced by other basketball shoes).

Still, the ultimatum is effective at silencing a lot of critical thinking. Before, when the shoes were just regular shoes, the decision to buy them was complex because all of your critical-thinking faculties were active. You were highly aware of the price and all of the possibilities represented by that money—all of the ways you could spend it, maybe even the work you did to earn it—and ultimately, you didn’t buy because you wanted the (continued) freedom of choice more than you wanted the shoes.

But when the shoes became limited-edition Jordans, the decision to buy them was much simpler—and also much likelier, especially if you’re a sneakerhead—because the whole offer was designed to force your attention upon the one thing in front of you, and for a decision right now. You technically maintain your freedom of choice, but unlike before, there are psychological penalties for every option except buying.

And therein lies the genius irony of scarcity-driven offers. To narrow the playing field of choice, you need only target a single option (as long as it’s attractive). After all, “free choice” means that they have full pick of the options; threaten one of those options and the whole choice is no longer fully free. In a lot of cases, this is the kind of bothersome that makes us buy.

The Wrap-Up

We wanted to stop and give Robert Cialdini’s principles of persuasion one last segment here—mostly because, when you’re talking about persuasion, you’re talking about something valuable.

To wrap everything up, we’re giving the best two pieces of advice we can offer from each of Cialdini’s principles.

Reciprocity 1: You must give value before you can expect to receive it, and it does you no good to begrudge the customer this exchange because you’re also entitled to it whenever you are the customer.

Reciprocity 2: You must continue to give value before you can expect to continue receiving value. The relationship with the customer is just that: a relationship, which requires continuous maintenance and investment in order to stay healthy. This is why Customer Service is essential for good business: it’s how the customer feels safe after they’ve given you their money, which is the best condition for helping them spend more money in the future.

Commitment and Consistency 1: Start with their ‘Why’, not with yours. The only way to convince someone is to start with what they know and believe, especially about themselves. It doesn’t matter how much sense something makes to you (or how much you want it) if it doesn’t make sense to the other person (who genuinely might not want it).

Commitment and Consistency 2: It’s easier to convince people the more of a (real) interest you take. This is partly because, yes, you are able to use the extra information you might find. But more importantly: it’s always easier to sell something you genuinely believe in, and for marketers a big part of that is believing in the people you’re selling to—not just the product you’re trying to sell them. Know your people and know them as well as you can.

Social Proof 1: Get your bleeping testimonials in order. It will always, always, always be harder to sell something if people can’t find someone else who says it was worth it. Think about it: the difference between 1 positive review on your site and 0 is a massive psychological gap for buyers.

Social Proof 2: Make the most of social sharing and virality. This is just a force of nature for social animals, and it’s a loss for marketers not to have some way of tapping into it. Remember that, if you’re providing value to your audience, you’re automatically creating a chance that it will benefit them to share that value with others—and most of your job here is to make that easy to do, for whenever they feel compelled to do it.

Authority 1: Demonstrate the crap out of your authority. Really and truly, this is not the time to be modest (if you are). People are far more interested in the power that comes from your expertise, competence, and confidence than they are the non-power that comes from your modesty. Remember that it’s not bragging if it’s true, and that a little pause to mention some credentials can shade the rest of your words favorably.

Authority 2: Whenever possible, borrow authority. You might be super-awesome in a handful of different ways, but nobody’s awesome in every single way. This is why Shaq is in so many commercials: nobody else is as tall, deep-voiced, and likable all at the same time. (And he probably likes money.) More generally, don’t be afraid to give credit openly; consider that this series has the feel of ‘expert authority’ not because we’re experts, but simply because we’re citing the expert’s work.

Liking 1: Don’t be afraid to get niche and nerdy. First of all, liking is one of those areas which is kind of infectious; this might sound dumb, but people like people who like things. If you’re positive and excitable and you engage on some topic because you’re genuinely geeking out about it (and it’s relevant to your market), people in your target audience will WANT to pay attention.

Liking 2: Keep as many people as familiar with you(r brand) as you can. This is because familiarity breeds liking, and just having a reason to be allowed and welcome in someone’s mind will make you more likable by itself over time. To our deeper lizard and monkey brains: just knowing who someone is and that they’re not a threat goes a long way, and you can prove that slowly over time just by existing where people see you.

Scarcity 1: Identify as many forms of scarcity as could possibly, genuinely exist in your customer’s mind. Bear in mind that you might need to think outside the box here. Scarcity isn’t just about quantity or time; it’s also about opportunity and value, whose definitions are constantly shifting.

Scarcity 2: Whenever and wherever it exists, make scarcities more visible and obvious to your customers. This is one area where Amazon excels: making an item’s many possible forms of scarcity easily visible at all times, but without ever making you feel like it’s forced or artificial or “loud.” So much of scarcity is subtlety; because it doesn’t take much to get our brains thinking in that direction, less really is more (as long as it’s there at all).

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