The Most Powerful Principle of Influence Is…

I get this question all the time:

“Which principle of influence is the most powerful?”

My answer?

It depends.

(Yeah, I know—that’s not as satisfying as a silver bullet answer. But when it comes to human behavior, one-size-fits-all just doesn’t work.)

Influence Is Contextual

Human decision making and behavior is complex. That’s why I teach three frameworks to help people understand when to use which principle of persuasion. Success depends on knowing how to apply the right principle at the right time, with the right person.

Let me walk you through the three frameworks:

1. Core Motive Model (from Dr. Gregory Neidert)
Dr. Gregory Neidert, Dr. Cialdini’s partner at INFLUENCE AT WORK, developed this model. The key is knowing what you’re trying to accomplish.

• Build relationships?
• Help someone overcome uncertainty?
• Get someone to take action?

2. The Sales Cycle
From prospecting to referrals, each stage of the sales process benefits from different principles.

3. DEAL Model (Dealing with Personalities)
Even when the message stays the same, how you deliver it should vary depending on the person in front of you. Same message, different path.

A Story of Unity…and Consistency

Here’s a real-life example from my own world.

My best friend, Russell—best man at my wedding—has been working just an hour and a half from my house. Naturally, I invited him to come stay for the weekend. But he said no.

Why?

Despite having nearly 50 years of close friendship and experiences (Unity) under our belt, consistency drove his decision. He’d promised someone else that he would help them move some furniture over the weekend. He made a promise, and sticking to that commitment mattered more than doing something he might’ve preferred.

That’s the beauty of understanding these principles. One principle doesn’t “win” in all situations. It’s about which one fits best at that moment.

Social Proof vs. Authority

Both Social Proof and Authority help people move past uncertainty. But when should you lean into one over the other?

• Fact-based decisions? Use Authority. People trust experts when the data matters.
• Preference-based choices? Use Social Proof. We tend to follow people like us when making subjective decisions.

Let’s say you’re buying a mattress. If you want the best-rated for spinal alignment, you’ll likely seek an expert (Authority). If you’re after what’s most comfortable, you’ll check reviews from folks who’ve actually slept on it (Social Proof).

Reciprocity: The Wild Card

We love to say yes to friends—and even more so when they’ve done something for us. That’s Reciprocity. But get this: Reciprocity is so powerful, we’ll often say yes to people we don’t even like, just to “even the score.”

It’s not about feelings—it’s about the psychological need to balance the scales.

Beyond Definitions: Knowledge vs. Wisdom

Here’s something I see all the time:
People believe they understand influence because they can define the principles.

But wisdom isn’t in the knowing—it’s in the applying.

Real influence happens when you move from knowledge to application. That’s where behavior changes. That’s where relationships deepen. That’s where professional success and personal happiness take root.

And that’s why I do what I do.

Want to Go Deeper?

If you’re ready to move from “I know that” to “I’m very good using that,” here are a few ways I can help:

• My Website – 15 years of blog posts, 200+ podcast episodes, and practical videos
• My Books – Real-life application of Dr. Cialdini’s principles in a relatable way
• LinkedIn Courses – Learn how to use influence in sales and coaching
• The Cialdini Institute – Whether you want to take a course or become a certified trainer, I’ve got your back

Influence Is a Life Skill

With the recent birth of our first grandchild, Emmett, I’ve been reminded: influence starts early. Crying? That’s influence. Smiling? Influence again. Emmett gets what he wants and needs!

In our careers, we use influence every single day. In fact, studies show we spend around 40% of our workday using the skill of influence—and that doesn’t even count our time at home.

So, if you’re using a skill that often…doesn’t it make sense to learn how to use it well?

I believe the ability to ethically influence PEOPLE (Powerful Everyday Opportunities to Persuade that are Lasting and Ethical) is the critical skill for achieving your professional goals and personal happiness.

Edited by ChatGPT

Brian Ahearn

Brian Ahearn is the Chief Influence Officer at Influence PEOPLE and a faculty member at the Cialdini Institute.

An author, TEDx speaker, international trainer, coach, and consultant, Brian helps clients apply influence in everyday situations to boost results.

As one of only a dozen Cialdini Method Certified Trainers in the world, Brian was personally trained and endorsed by Robert Cialdini, Ph.D., the most cited living social psychologist on the science of ethical influence.

Brian’s first book, Influence PEOPLE, was named one of the 100 Best Influence Books of All Time by Book Authority. His follow-up, Persuasive Selling for Relationship Driven Insurance Agents, was an Amazon new release bestseller. His latest book, The Influencer: Secrets to Success and Happiness, is a business parable designed to teach you how to use influence at home and the office.

Brian’s LinkedIn courses on persuasive selling and coaching have been viewed by more than 750,000 people around the world. His TEDx Talk on pre-suasion has more than a million views!