If you're like most people, you probably think you're a better driver than the average person. No doubt you're a more reasonable and kinder person, and heck you're probably better-looking and smarter too.

Key points: People were significantly more confident of their results on an intelligence test when they knew they had an opportunity to convince others of how well they'd done

People were significantly more confident of their results on an intelligence test when they knew they had an opportunity to convince others of how well they'd done Overconfidence can benefit the individual if it helps them be more persuasive

Overconfidence can benefit the individual if it helps them be more persuasive It's not necessarily great for society, researchers say

Overconfident much?

Our tendency to overrate our abilities is something that's been known about for years, but there have been different theories as to why this phenomenon is so prevalent, given we can't all be flawless drivers, with movie star good looks and genius IQs.

One idea put forward by evolutionary biologist Robert Trivers and psychologist Bill von Hippel in 2011 is that we deceive ourselves into being more confident than we should be, because such self-deception is extremely useful when it comes to more effectively persuading or deceiving others.

Now European researchers have put this theory to the test, in a study published in Nature Human Behaviour.

Participants in the study took an intelligence test, and then were asked to judge how well they thought they performed, compared to three other subjects randomly selected from the group.

Half had been told they could earn 15 euro ($24) later in the experiment if they were able to convince other subjects, who were posing as mock employers, that they did really well on the test.

Making people feel more confident about their performance in the test led them to them performing better when they were interviewed by a mock employer. ( Unsplash CC: Nik MacMillan )

"We really wanted to test two things," said behavioural economist Peter Schwardmann of the University of Munich and lead author of the study.

"If we know that we have to persuade others about our quality, does this knowledge alone inspire us to self-deceive into higher confidence — to interpret the evidence around us in a way that leads to better judgement of ourselves?

"And the second is well if we do this, is higher confidence actually valuable? Does it actually help us convince others?"

What they found, Dr Schwardmann said, is that the participants who knew they would have an opportunity to convince others later were significantly more confident than the control group.

Before the participants sat down face-to-face with their mock employers to try to convince them of how well they had done, they were first given feedback about their performance on the test.

But the feedback wasn't correct all of the time. So for example some people who were in the top half of the results were told they weren't, while others in the top half were told they were, according to Dr Schwardmann.

"The only thing that was different between them was how they felt about their performance."

But this had a significant impact in the interviews, with the more confident participants performing better in both verbal and non-verbal cues.

Interestingly, the researchers found that women engage in as much or slightly more self-deception than men, although their absolute levels of confidence were still lower.

Does the evidence stack up?

This is a great first step at trying to unpack why it is that we act the way we do, according to behavioural economist David Savage of the University of Newcastle, who was not involved in the study.

But he's not convinced that there's strong enough evidence in the study to fully support the researchers' findings.

He pointed to the researchers' comments in the paper acknowledging it was hard to distinguish between participants' actual performance and their beliefs about their performance, although Dr Schwardmann said this only affected part of the study.

But Dr Savage said it was exceptional that the researchers ran the experiment twice with 688 total participants, and got similar and statistically significant results both times.

"That tells me there is definitely something going on, I'm just not 100 per cent sure it's what they think it is."

Is overconfidence good or bad?

Someone's desire to become a pop star could lead them to over-judge their singing ability. ( Unsplash CC: Vidar Nordli-Mathisen )

While overconfidence can be seen as a negative social trait, it may have benefits according to Dr Schwardmann.

"I actually think that in our case this overconfidence is going to be valuable to the individual, if it helps you be more successful because it persuades employers, spouses and in general those people around you," he said.

But Dr Savage agrees that overconfidence is becoming more and more of a problem in society.

"The more people that think they're overconfident, they over-judge their skill, they over-judge their abilities and they over-judge what's going to happen," he said.

"How many people believe they'll become a pop star? How many people believe they're going to become a social media sensation overnight?"

And that means they might not choose a role they'd be good at because they're more focussed on the role they want to be good at.

"One thing that our experiment and experiments of this type help us do is ask, 'where do we expect people to be overconfident?'," Dr Schwardmann said.

Typically, overconfidence is found in professions that are highly competitive, where it's not easy to judge someone's actual performance, and where you benefit from persuading others — like politics.

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We can look at Boris Johnson and Donald Trump as examples of politicians who use overconfidence to their advantage, Dr Savage said.

"They're speaking directly to a lot of people that are disaffected, and they're very confident about it, and it works," he said.

The problem according to Dr Savage, is when overconfident people can't live up to the hype.

"At the end of the day the bill still comes due, and you go well great, we put this person in power and look what's happened. Who's responsible? Well you people for voting. So overconfidence can be dangerous."