Marketing Psychology: 4 Timeless Principles for Being More Persuasive

Marketing is how you connect customers to products, so of course psychology, the study of human behavior is important to effective marketing.

It’s also true that marketers can get overly obsessed with research that has yet to be put into practice—the results from a single academic experiment mean little in the real world unless they’re tested. That said, there are a number of psychological principles in marketing that are Lindy, meaning that they’ve been tested and found useful time and time again.

That’s what we’re going to focus on here. When I covered the psychology of color a few years ago, the standard I held was that I wouldn’t accept any study at face value. And the same applies here: for every piece of research we cite, let’s also explore the real-world implications and how marketers actually use the principle for their campaigns. (Results matter. If the math doesn’t work, your marketing doesn’t work.)

Let’s get into the research. Here are five principles from psychology that marketers can make use of.

Learn more: My bookshelf is filled with tomes on persuasion and human behavior—I’m a marketer, after all. Recently, I curated a list of my favorite psychology books that I think any curious person can learn from.

Psychology principles for marketers

1. Reciprocity

Reciprocity is maybe the most famous social psychology concept. Reciprocity is the social norm that says any positive or charitable gesture will encourage the recipient to reciprocate, hence the name.

Of course, we all know a few people to whom this doesn’t apply. But the research has consistently shown that reciprocity does, on average, create goodwill for you or your business. One of the earliest studies on this phenomenon by Norbert Schwarz found that at little as ten cents—about a quarter in today’s dollars—could build reciprocity with recipients.

In one of the industry’s best marketing books on human behavior, author Robert Cialdini shares another study where subjects rated researchers, who were disguised as subjects, as more likable if they offered them something to drink.


Small gestures can be both meaningful to customers and cost-effective for your business. The way to make reciprocity work is to focus on surprise and relevancy—what’s something small you can do for customers that they don’t expect and that relates to what your business offers?

2. Foot-in-the-door effect

The foot-in-the-door effect describes our increased likelihood of saying yes to a large request after saying yes to a small one. Psychologists posit that the foot-in-the-door effect works the way it does because we inherently want to be consistent in our decision-making. If we agreed to help to contribute to an individual person’s specific request, why wouldn’t we do so again?

Of course, extreme examples can always highlight when a concept like this falls apart. You probably won’t feel pressured to accept my offer to buy my car on the spot just because you bought a stick of gum from me earlier. But, this principle obviously does have a lot of real-world applications, especially in sales. Salespeople commonly close large deals by getting prospects to consider small options first.

Recently, another study on the foot-in-the-door effect was published. Half of the subjects were asked to sign a petition against drunk driving, and half were not asked. Those who were asked all signed the petition—it didn’t take much to do.

However, researchers found that the group who signed the drunk driving petition was significantly more likely than the control group to call a taxi to drive home after drinking alcohol. The small request led to higher compliance with a larger request, and the researchers theorized that subjects again wanted to remain consistent with their previous decisions and actions.


Large sales or marketing requests that take effort can possibly be aided by having prospects take a smaller, easier action beforehand. The thing to keep in mind is consistency: people want to be viewed as consistent, so the small action should feel like it ladders up into your more significant request—if the actions aren’t related, you’re unlikely to be persuasive.

3. Framing Effect

The framing effect is a cognitive bias that states that our likelihood to select between multiple options is directly affected by whether or not the options are presented in a positive or negative light. That may seem obvious, but the concept applies even when the change in framing (for the same ask) is more subtle.

The most famous experiment around the framing effect was conducted by psychologists Amos Tversky and Daniel Kahneman, where they asked subjects to make a decision between a hypothetical life or death scenario. The scenario was that 600 patients were being treated for a deadly disease, and the two treatment options came with different survival rates.

Treatment A

  • Positive: “Saves 200 lives.”
  • Negative: “400 people will die.”

Treatment B

  • Positive: “A 33% chance of saving all 600 people, 66% possibility of saving no one.”
  • Negative: “A 33% chance that no people will die, 66% probability that all 600 will die.”

The results? Treatment A was the most popular framing by far, chosen by 72% of participants when it was given the positive framing. When the negative framing was applied, it was only chosen by 22% of subjects—fewer than a third when compared to the positive framing.

The net result of this hypothetical choice was, of course, the same, since 400 people would live. But the framing of the choice, that your decision as a subject was saving lives, made all the difference.

4. The Power of 9

Have you ever wondered why most prices end with the number 9? Common sense tells you that it allows businesses to drop the first number in the price, e.g. $400 to $399, but that doesn’t tell us if this approach actually works, or why.

In the book Priceless, author and researcher William Poundstone describes these prices as “charm prices.” Across eight different studies, Poundstone found that charm prices increased sales by 24% when tested against the nearest rounded price.

What’s more, an experiment from MIT tested a charm price for a woman’s clothing item against both a higher and a lower price. Surely the lower price helped the item sell more, right? To their surprise, researchers found that the item sold more often when it was priced at $39 instead of $44 and even at the lower $35 price.

About the author: Gregory Ciotti is a writer and consultant. Previously, he led content marketing on Shopify’s growth team and was executive editor on the communications team. Greg is a fan of simple websites, salty food, and writing that’s clear as a country creek.