Mastering Persuasion and Credibility - Nonverbal cues that matter most

Discover how nonverbal communication shapes perceptions of credibility and persuasiveness via leading scientific research. This article delves into the dimensions of pleasantness, potency, and arousal, revealing how mastering body language, tone, and vocal cues can enhance your influence. Learn from the techniques of influential figures and unlock the secrets to becoming more persuasive in your personal and professional interactions.

Sep 23, 2024
Mastering Persuasion and Credibility - Nonverbal cues that matter most
In today’s era of brainrot, information overload and yap, what makes some voices rise above the rest? We can often intuitively identify whether someone is persuasive and credible, but pinpointing exactly why can be so so difficult. This article aims to unpack the factors that lead to credibility and persuasion, and I’ll show you exactly how how controversial figures like Andrew Tate or Donald Trump can be simultaneously polarising and incredibly persuasive.
When I was undergoing sales training, I’ve heard the mantra that over 90% of sales skills stems from body language and tone - your nonverbal cues rather than the exact words themselves - but what does this really mean? How can we more deeply understand the nuances of tone and body language?
 
notion image
Lets investigate the specific nonverbal behaviours that you can refine to enhance your persuasion and credibility, and unravel the mystery of what exactly makes up credibility and persuasion.

The Three Main Dimensions of Persuasiveness

Okay, let's break this down. There are tons of factors in your voice tone and body language that affect how persuasive you are. It's a mess trying to categorize them all - trust me, the world’s leading scientists have tried. But it’s possible to boil it down to three main dimensions that really impact your credibility and persuasion power:
  • Pleasantness
  • Potency
  • Arousal
The following diagram from this study highlight each of these relationships:
Relationship Among Distal Cues, Proximal Percepts, and Credibility and Persuasiveness Attributions (https://doi.org/10.1111/j.1468-2958.1990.tb00229.x)
Relationship Among Distal Cues, Proximal Percepts, and Credibility and Persuasiveness Attributions (https://doi.org/10.1111/j.1468-2958.1990.tb00229.x)
It’s important to note that although there are so many dimensions that affect credibility, such as character and competence, persuasion can only be measured as one variable. For example in sales you only have one metric to measure → did the prospect buy or not?
It’s also interesting to note that Pleasantness had such a limited effect on Persuasion, however had a great effect on credibility. That’s really how characters like Tate or Trump seem to get away with saying whatever they want, while still being persuasive. So many people find them unpleasant, but they are still able to sway nations with a single speech.

Pleasantness Dimension

Lets talk about pleasantness, it basically measures how agreeable you sound, and it’s measured by things like fluency, tempo, pitch variety, clarity and voice quality. Smoothy, happy speech sounds more pleasant and more credible.
What’s surprising and incredible from the research I’ve done is that non-fluencies (like sudden stops, ums and ahs) hurt your credibility, but don’t actually hurt how people judge your character, and might even make you seem more sociable.
This piece of research finally helps understand myself and so many other people that stutter and has had discontinuities in their speech. It means that while people won’t take what you’re speaking about seriously (you’ll be less credible), it won’t take away what they think of you as a person, they won’t think you’re a liar or untrustworthy.
But from my experience, this makes it very explicit how you’ll be knocked down the group hierachy if you stutter or stop speech. You’ll end up in a role below your skill level, but people will find you more approachable because you won’t be seen as a threat.
So what boots your competence? Quick responses. The quicker back you fire back and answer, the more competent you will seem. But the trade-off in response time is trustworthiness. Medium-response times make you seem more trustworthy. So if you’re lightning fast with your response latency, people will think, “Hey, they’re sharp”, instead of “I’d trust them with my life”. That’s why expert communicators tailor their response speed to optimise for trust or competence depending on the situation.
All of this isn’t fair and I used to struggle with this quite a bit too and beat myself up. Just because you take more time to understand and process something doesn’t nessasarily mean you’re less competent or smart. But the key is to turn these negative feelings into positive actions. Use them. Figure out your strengths and how to play them.

potency dimension

Now, lets talk about potency. It measures how powerful, authoritative and dynamic you sound. Basically, it’s a measure of how much of a leader you come across as.
Temp is one of the biggest contributors in the potency game. You ever notice how some of the most influential speakers talk at a lightning speed, far higher than normal conversation? Check out some of these master persuaders and their speed, loudness and intensity:
 
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Video preview
Video preview
 
Notice that there’s a sweet spot for speed however. Think back to a time where you notice someone speaking slow in your life, and feel how boring they sounded, half asleep. Slow speed tanks your competence and persuasiveness. However on the flip side talking too fast makes you sound anxious and nerdy. That said, when combined with other traits like perfect tone it’s hard to talk too fast. Tate surgically talks extremely fast in certain segments to highlight a point, without detracting from persuasiveness or credibility.
Loudness is another big factor in potency, and this one is pretty obvious, if you’re speaking too quietly, you’re not going to sound very dominant or dynamic. The good news is that if you’ve got a quiet voice, loudness is one of the easiest factors the change and work on. But don't go overboard - yelling isn't the answer either. Lose control of your volume, and you'll lose control of your audience.
Now, intensity and variety also play into potency, but they're trickier to nail down. I'll dive deeper into these in a future article, so keep an eye out for that.
Now, intensity and variety also play into potency, but they’re much harder to nail down exactly what they are and how to change them. I’ll dive deeper into these in future articles, so make sure to subscribe to our email list!
Paradoxically, one of the most interesting things about potency though, is that while a high potency can make you seem more competent and dynamic, they can have a strange effect on how approachable you seem. People are often scared and anxious upon meeting a high potency person. Sometimes dialing it back and going for a softer more conversation style can make you seem more human, trustworthy and friendly. It’s all about understanding the room and triggering the potency muscle strategically.

Arousal

Lastly for arousal (and no, quit it with the dirty mind, not that kind of arousal). Arousal is how much you can spike the audience’s emotions. How much thrill you can inject into the audience through your speech or conversation.
While potency is all about sounding powerful and authoritative, arousal is about getting your audience fired up and injecting that emotion into their bloodstream. You can sound cool, calm and collected with a high potency, but if you can’t get your audience emotional, you won’t be able to persuade them. Even the most authoritative, knowledgable person in the room is gonna struggle in sales, relationships and leadership if you can’t excite your audience.
So what goes into arousal? Here are the key ingredients:
  • Fluency (how smoothly you speak)
  • Response Latency (how quickly you reply)
  • Tempo (your speaking speed)
  • Loudness (volume, baby!)
  • Pitch (high or low voice)
Now, arousal is probably the most difficult proximal dimension to master due to the fact that it’s full of paradoxes and have a bunch of interdependent and factors. Things that can tank your credibility like “ums” and “ahs”, long pauses that can tank your credibility, can actually crank up your audiences arousal if implemented correctly.
It’s a delicate art to spike someone’s emotions. It’s a game of milliseconds. An erratic tempo can make you sound anxious, but a smooth fast tempo? That signals competence and dynamism. High pitch alone can make you sound nervous, but if you add variety to the pitch, you’re suddenly competent and sociable. Loud voice? Could be anxiety... or it could be dominance and competence if mixed in with the correct cofounding factors.

The Secret Sauce of Persuasion: Decoding the Nonverbal Behaviour Matrix

Let me show you the magnum opus of persuasive behaviours. This piece of research sets out correlations between behaviours to show how each of these behaviours are linked. Some of these links are wild.
First things first: any correlation above 0.25 is significant. That means it's not just random chance - there's a real relationship there. Now, let's break this bad boy down and see what it means for you.
 
Behavior
Fluency
Pitch variety
Vocal clarity
Tempo variety
Tempo
Loudness
Pitch
Immediacy
Kinesic express.
Self-adaptors
Object-adaptors
Random movement
Body relaxation
Fluency
-
0.22
0.27
-0.10
0.02
-0.12
0.09
0.06
-0.03
0.21
0.06
-0.03
-0.11
Pitch variety
0.22
-
0.48
0.24
0.59
0.04
0.37
0.62
0.56
-0.15
0.21
0.42
0.37
Vocal clarity/pleasantness
0.27
0.48
-
0.15
0.38
-0.04
0.13
0.40
0.31
-0.03
0.41
0.33
0.35
Tempo variety
-0.10
0.24
0.15
-
0.20
0.15
0.10
0.37
0.42
-0.12
0.13
0.05
0.30
Tempo
0.02
0.59
0.38
0.20
-
0.27
0.28
0.11
0.05
-0.14
0.13
0.05
0.09
Loudness
-0.12
0.04
-0.04
0.15
0.27
-
-0.03
0.00
-0.11
-0.07
0.18
-0.08
-0.03
Pitch
0.09
0.37
0.13
0.10
0.28
-0.03
-
0.18
0.09
0.33
0.02
0.03
0.13
Immediacy
0.06
0.62
0.40
0.37
0.11
0.00
0.18
-
0.67
-0.07
0.28
0.53
0.59
Kinesic expressiveness
-0.03
0.56
0.31
0.42
0.05
-0.11
0.09
0.67
-
-0.14
0.10
0.62
0.64
Self-adaptors
0.21
-0.15
-0.03
-0.12
-0.14
-0.07
0.33
-0.07
-0.14
-
-0.05
-0.18
-0.11
Object-adaptors
0.06
0.21
0.41
0.13
0.13
0.18
0.02
0.28
0.10
-0.05
-
0.25
0.04
Random movement
-0.03
0.42
0.33
0.05
0.05
-0.08
0.03
0.53
0.62
-0.18
0.25
-
0.56
Body relaxation/fluidity
-0.11
0.37
0.35
0.30
0.09
-0.03
0.13
0.59
0.64
-0.11
0.04
0.56
-
 

Pitch Variety: Your Secret Weapon

Ever wonder why some speakers just grab you? It's all about pitch variety, baby. Here's the deal:
  • It's strongly linked to immediacy (0.62 correlation). That means when you vary your pitch, you're subconsciously telling your audience, "Hey, I'm right here with you." It's like you're reaching out and pulling them in.
  • It goes hand in hand with body language (0.56 correlation with kinesic expressiveness). So when you're vocally dynamic, your body follows suit. You become a full-package performer.
  • It makes you clearer (0.48 correlation with vocal clarity). Varying your pitch isn't just for show - it actually helps people understand you better.
 
So what does this mean? Firstly Correlation doesn’t equal causation, so it’s not guaranteed that varying your pitch will help you improve your body language, but it might just make you more aware and highlight those behaviours. The brain works in very mysterious ways, when one pattern of action is disrupted it’s more likely other patterns will get disrupted too.
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Action step: Practice speaking with more vocal variety. Try emphasizing different words, or experiment with raising and lowering your pitch throughout your sentences. Record yourself and listen back - you'll be surprised at the difference it makes.
 

Get Your Body in the Game

Like we’ve described, your body language is screaming information about you, whether you like it or not. Here’s how to understand it and make it work for you:
  • Expressive gestures and facial expressions make you more approachable (0.67 correlation with immediacy). It's like you're sending out "come talk to me" vibes.
  • Relaxed body language plus expressiveness is a winning combo (0.64 correlation). It says, "I'm confident and engaging."
  • Be careful with random movements though (0.62 correlation). A little fidgeting can make you seem real, but too much and you'll look nervous.
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Action step: Next time you're in a conversation, focus on using purposeful gestures that match your words. Keep your body relaxed but engaged.

Tempo: The Rhythm of Persuasion

Your speaking speed is more important than you think:
  • Fast tempo often goes with pitch variety (0.59 correlation). When you speed up, you naturally vary your pitch more, making you sound more dynamic.
  • But don't forget clarity (0.38 correlation with vocal clarity). Find that sweet spot where you're speaking quickly enough to be engaging, but not so fast that people can't follow.
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Action step: Try speaking about 10% faster than you usually do. But here's the trick - maintain your clarity. It's a balancing act, but master this, and you'll sound like a pro.

Immediacy: Bridging the Gap

Immediacy is all about making your audience feel close to you, both physically and psychologically:
  • It's linked to both vocal variety (0.62) and body language (0.67). This means it's not just what you say, it's how you say it and how you move while saying it.
  • When you nail immediacy, you spike arousal and persuasiveness. You're not just talking at your audience; you're connecting with them.
💡
Action step: Practice maintaining eye contact, using inclusive language ("we" instead of "I"), and physically leaning in slightly when making important points.
 

Fluency: Smooth Operator

Being fluent isn't just about not stuttering. It's about smooth, confident delivery:
  • It's tied to vocal clarity (0.27 correlation). The more fluent you are, the clearer you sound.
  • Interestingly, it has a slight positive correlation with self-adaptors(fidgeting) (0.21). This suggests that some nervous gestures might actually help your fluency. Maybe they're a sign of enthusiasm?
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Action step: Work on eliminating filler words like "um" and "uh". But don't stress if you use your hands a bit while speaking - it might actually be helping you stay fluent!

The Self-Adaptor (fidgeting) Paradox

Those little nervous habits? They're not all bad:
  • They're positively correlated with fluency (0.21) and pitch (0.33). This suggests that some self-touching (like adjusting your glasses) might make you seem thoughtful rather than nervous.
  • But watch out - too much can reduce your pitch variety (-0.15 correlation), making you sound monotonous.
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Action step: Don't try to eliminate all self-adaptors. Instead, be mindful of them. Use them purposefully to create pauses or emphasize points, but don't let them dominate your presentation.

Relaxation: The Foundation of Confidence

Being relaxed is your baseline for great communication:
  • It's strongly linked to expressiveness (0.64) and immediacy (0.59). When you're relaxed, you're free to be expressive and engaging.
  • It even affects your voice, correlating with vocal clarity (0.35) and tempo variety (0.30).
💡
Action step: Before any important communication, take a few deep breaths. Relax your shoulders and jaw. A relaxed body leads to relaxed, confident communication.

What’s next?

Alright, you've got the tools, you've got the knowledge - now what? It's time to put this stuff into practice. Start small: pick one or two techniques we've discussed and consciously apply them in your next conversation or presentation. Maybe focus on varying your pitch or working on your body language. Record yourself, watch it back (yeah, it's awkward, but do it anyway), and see where you can improve. Remember, this isn't about becoming someone you're not - it's about amplifying your natural strengths and minimizing your weaknesses. As you get more comfortable, start layering in more techniques. Before you know it, you'll be communicating with more power, authenticity, and persuasiveness than you ever thought possible. So go on, get out there and start influencing! Your audience is waiting.

References

BURGOON, J.K., BIRK, T. and PFAU, M. (1990), Nonverbal Behaviors, Persuasion, and Credibility. Human Communication Research, 17: 140-169. https://doi.org/10.1111/j.1468-2958.1990.tb00229.x