What makes a voice persuasive

Voice tones that sound stressed (-27%) and emotional (-29%) are less likely to persuade. A focused, low-pitched tone is most effective (+30%)

Welcome fellow 3,141 evidence-based marketers to today’s 3min marketing tip 💡 based on research 🎓 New here? You can subscribe below at no cost

The authors of today’s research used voice tone analysis software to reliably study what vocal tones are more persuasive than others.

Their findings are based on 10,721 Kickstarter fundraising pitches and two experiments. This means we now know for a fact what works, rather than relying on varying opinions or our gut feeling.

Thank you Dr. Mansur Khamitov (Kelley School of Business, Indiana University) for sharing another one of your great studies with Ariyh. 

In case you missed it, this other tip based on his research is very handy for most brands: ‘If customers feel distant from your brand, use abstract language’.


Use a focused, unstressed, and low emotion vocal tone to be more persuasive

Impacted metrics: Customer acquisition
Channels: Video ads | Sales team | Customer service | Marketing communications
For: Both B2C and B2B

Tip type: New research (February 2021)
Previous tip: The downside of company uniforms (All tips here)

Recommendation

When you’re persuading someone (e.g. promotional videos, sales pitches), use a tone of voice that sounds:

  • Focused (concentrated on what you’re saying; using a low-pitch voice helps)

  • Not stressed (confident of what you’re saying)

  • Emotionally stable (calm and relaxed)

You’ll be more likely to persuade successfully (e.g. sign up to your website, buy from you, fund your company).

Effects

  • Kickstarter campaign pitches tend to receive more funding when the voice tone is focused, not stressed, and emotionally stable (see correlations in images below).

  • In an experiment, the willingness to fund a project* was:

    • 30.5% higher when the tone was focused

    • 26.3% lower when the tone was stressed

    • 29.1% lower when the tone was very emotional

  • A low-pitched tone of voice seems to be one of the main drivers of a focused sounding tone of voice, boosting funding by 27.4% in another experiment.

  • An additional effect found is that video pitches with high brightness reduce the willingness to fund.

*Fun fact: in this experiment, researchers created different variations of the Kickstarter pitch for the COOLEST Cooler, which raised more than $13 million. However, it’s considered one of the biggest Kickstarter disasters for not delivering. (This didn’t affect the experiment).

(The analysis of Kickstarter campaign funding found correlations with a voice tone’s focus, stress, and emotions. Dark areas show 95% confidence interval - Click to zoom in)


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Why it works

  • We believe speakers that sound focused and not emotional or stressed are more competent.

  • If they sound more competent, we expect they’re more likely to deliver on their promise.

  • If we believe they’ll deliver, we’re more likely to be persuaded.

Limitations

  • The study analyzed actual spending on Kickstarter music and technology campaigns, then ran experiments to establish the cause-effect. This means results are strong in the Kickstarter funding context. The effects were not tested in other contexts but it’s very likely that they’re generalizable.

  • It’s possible that an emotional tone in some situations signals passion (e.g. an entrepreneur for their project), which would have a positive effect. It’s unclear when this is the case.

  • It’s unclear how natural tone of voice variations by gender impact this effect.

Companies using this

  • For promotional marketing material (e.g. videos, podcast introductions), most companies hire professionals that tend to use an optimal tone of voice.

  • However, startup founders, executives, and sales teams use varying degrees of focus, stress, and emotion in their voices when pitching. Typically, this is due to inexperience, discomfort in public speaking, or a misguided feeling that an emotional tone is more persuasive.

Steps to implement

  • Train yourself and your sales team to use this highly persuasive tone of voice. For most people, it will require extensive practice.

  • For promotional videos or voiceovers you can hire professionals that are more likely to have this optimal tone of voice.


Study type

Online experiments and market observation (of 6,755 music and 3,966 technology projects on Kickstarter). United States

Research

Wang, X. S., Lu, S., Li, X., Khamitov, M., & Bendle, N. (February 2021). Audio Mining: The Role of Vocal Tone in Persuasion. Journal of Consumer Research.

[Link to paper]

Affiliations

Ivey Business School, Western University; Bauer College of Business, University of Houston; City University of Hong Kong; Kelley School of Business, Indiana University; and Terry College of Business, University of Georgia. Canada, United States, and Hong Kong, 

Remember: Because of the groundbreaking nature of this paper, it could be disproven in the future (although this is rare). It also may not be generalizable to your situation. If it’s a risky change, always test it on a small scale before rolling it out widely.


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