Facial Action Coding System (FACS): What Salespeople Should Know

The customer says, “That sounds good.”

You’re already thinking about the next step. But as you explain the timeline, their lips press together and their brow lowers. You keep talking. A few minutes later, you hear, “Let me think about it.”

What happened?

You don’t know yet. But that change in expression could have been a useful moment to pause and ask a question.

This is one reason the Facial Action Coding System, or FACS, interests me. My work with The Persuasion Edge focuses on human behavior, persuasion, and the conversations that influence decisions. Paying attention to facial movement fits naturally into that work—provided we stay careful about what we think we know.

I’m continuing to study FACS and have a working understanding of its foundations. I’m not yet a certified FACS coder. What I want to share here is why this system is worth understanding, and how its emphasis on careful observation can inform everyday communication.

FACS is a system for describing visible facial movement. Developed by Paul Ekman and Wallace Friesen, with its original manual published in 1978, it breaks movement into components called Action Units, or AUs. Researchers use it to describe what the face does in a systematic way. Interpreting the emotional meaning of those movements is a separate step. Paul Ekman Group: Facial Action Coding System

That distinction matters in sales.

“Their brow lowered” describes something you observed. “They hate my price” adds a story about what it means. Once you accept that story, you might start defending your price, offering a discount, or talking faster—before the customer has explained anything.

Consider a hypothetical sales meeting. You’re discussing a project with a business owner. The conversation seems comfortable until you mention that implementation will require time from their staff. Their expression changes, and their answers become shorter.

You could assume they’re losing interest. Or you could ask:

“How would that fit with your team’s workload right now?”

They might explain that two employees are already covering an open position. Suddenly, you have something concrete to discuss: the demands of implementation.

The expression didn’t tell you that. Their answer did. Your observation simply reminded you to make room for it.

This is how I would encourage a sales team to apply the underlying lesson: notice a change, consider what was happening, and invite the person to explain their perspective. That is an everyday communication habit inspired by careful observation; it is not formal FACS coding.

You might ask, “What questions does that raise for you?” or “What would you need to feel comfortable with the next step?” Then give the person time to answer. Avoid announcing, “I can tell you’re uncomfortable.” That turns your interpretation into a claim about someone else’s experience.

The same care applies to negotiation. If someone’s expression changes when you mention a deadline, ask how the timing works for them. If you notice a reaction while reviewing responsibilities, ask which parts need more discussion. Let their explanation guide your response.

And be especially careful about deception. A facial movement is not proof that someone is lying. The Paul Ekman Group explicitly cautions that no single expression, gesture, or muscle movement establishes deceit. Even an emotional reaction can have a cause unrelated to the conversation. Paul Ekman Group: Deception Detection

For me, the practical value of studying FACS is the discipline it encourages: separating what I notice from what I assume.

A customer’s face should never become an excuse to stop listening to their words. It can be a reminder to listen more closely, check your understanding, and give them room to explain what matters.

That connects directly with the approach behind The Persuasion Edge. Persuasion involves how we pay attention, how we respond, and how well we understand the person making the decision.

The next time a customer’s expression changes, try resisting the urge to immediately explain more. Ask a thoughtful question instead.

You may discover that the most useful thing you noticed was the moment to listen.

If this has you wondering what else you might be missing, facial movement is just one place to begin. My online body language course, Decode Anyone, explores patterns across the face, hands, posture, and the rest of the body, helping you build greater awareness in sales conversations, negotiations, and everyday relationships.

Bring that same curiosity to your next conversation. Explore Decode Anyone and start learning what to look for.