Meet Mike and Jeff.

They are both established professors at a top university. Both have written books in their field. Both are respected. Now, suppose you hear both of them speak on a subject of their latest research.


First Mike. Imagine he speaks with absolute certainty. Every cell in his body believes in the accuracy of their research. He is 100% certain.

Jeff on the other hand, allows for some doubt in what he says. He too has high certainty regarding their finding, but he allows for some doubt. Here and there he mentions that they are not absolutely sure about the result. If you were about to rate his certainty it would be around 90% mark.

Who do you believe more?

Surprising Expertise

Well you may believe whoever you want, but studies of Stanford’s Zakary Tormala have consistently shown that people would rather believe… Jeff.

How come? Turns out when the expert is not so certain, that’s surprising to receivers of the message.

What? But he was not certain! Surprised? You are on to something. It’s all about surprise.

“When the expert is not so certain, that’s surprising to [receivers of the message],” Tormala said. Surprise increases [receivers’] interest and involvement, which is essentially resulting in a persuasive message, promoting persuasion.”

Interestingly, if you are NOT an expert, you can benefit from the same surprise effect. Just do the reverse. Tormala continues: “We find that when the regular, everyday person is extremely certain, that’s surprising to [receivers]. So non-experts get more attention and can have more impact when they express certainty in their messages (…)”

How do you apply it to your everyday and special-occasion speaking interactions?

How to nail your next presentation

Depending on your actual level of expertise on a subject, choose the right strategy to boost your persuasion with the audience.

You Are A True Expert

If you are perceived as an expert in your field, allow for little uncertainty. Introduce a tiny bit of doubt. In fact, have doubts. Allow them to see that you are wondering whether something is absolutely true. Do not speak from the position of absolute certainty. This way you will promote higher persuasion rates among your audience.

They will find it surprising and tune in to your message.

You Are A Wannabe

If you are not perceived as an expert in your field then, you guessed it, ditch uncertainty. Speak as if you could put your house, mother and your life on it. Appear 100% certain regarding your words to stimulate persuasion. You will be better off.

However be sure to not overdo it when it comes to levels of confidence you will be projecting. Being certain and being cocky are not the same thing. You don’t want to end up like this guy.

Over to You

Are you perceived as an expert by your audience? I don’t have to tell you that you better be sure of your actual status. Carefully assess this before your speech, so that your sneaky use of uncertainty does not backfire!

Now tell me:

  • How surprised are you by these findings?
  • Have you instinctively used these to your advantage before?
  • Which way? How did it go?

Leave a comment now.

Wojciech is a trainer, teacher and life-long learner on the topic of effective communication. He believes that speaking clearly, effectively and with confidence is essential to our success and taking advantage of all life’s opportunities. READ MORE