OPINION12 July 2016

Cognitive biases that made us Brexit

Behavioural economics Brexit Opinion UK

No political event in living memory provoked such a reaction as Brexit. Shock and incredulity from the chattering classes and media fraternity continues to dominate the news and social media, Adele Gritten looks at the biases that affected voting behaviour.


So why did 17 million people defy the ‘experts’, who prophesised a decade of doom, gloom and misery? What made the British electorate vote for a step into the unknown? Ultimately, our brains, and how they are wired, were crucial to Leave’s success. If we turn to behavioural economics and some cognitive biases that affected voting behaviour in the referendum, we gain some clarity on what resonated with the voting majority and why.

Confirmation bias. This is a tendency individuals have to interpret new evidence as confirmation of their own beliefs or theories. It’s a bias whereby we know what we want to believe, so we mould and interpret stimuli or information we are given to fit pre-existing beliefs. 

While Remain were keen during the campaign to point out the inaccuracy of the weekly £350 million payment to the EU, Leave were still able to distort those facts to suit a particular narrative i.e. even if the figure was lower than £350 million after the rebate, they insisted that it was still too much and would be £0 in the event of Leave.

Framing. ‘Project Fear’ became a soundbite used by Leavers to lambast perceived scare-mongering Remainers about their bleak narrative. Here, Leave used the framing effect for competitive gain: essentially, better judging how people would react to various scenarios and information presented, based on how it was presented.

Although Brexiters criticised Remainers for playing on people’s fears, they themselves actively leveraged anxiety and insecurity centrally within their story. An example would be Leave’s leaflet highlighting the alleged future reality that Turkey would join the EU. The leaflet showed a map highlighting Turkey in red, positioned next to Iraq and Syria with no other European countries in sight, even though Turkey also shares its borders with Bulgaria and Greece. 

Effective marketing using framing combines what is to be gained with what can be avoided. Leave posited that staying in the EU would mean population overload (hence should be avoided) but the gain from leaving would be greater – reclaimed autonomy, freedom and control.

This also plays into Leave’s use of the decoy effect. Known alternately as an asymmetrically dominated choice, it occurs when people’s preference for one option over another changes as a result of adding a third, similar, but not so attractive, option.

For example, people are more likely to choose a nice pen over a small cash option if there is a third option of a less elegant pen! When voters were faced with choosing between Brexit (lead largely by Boris and Gove), Remain (led largely by the Cabinet of the day) and a perhaps more extreme Brexit option led by UKIP – ‘Leave.eu’, the public voted for the least-worst Leave option. Rather like opting for the least-worst pen!

And last but not least, reverse psychology was used to maximum effect by Leave. The more I tell my young daughter not to do something, the more she is likely to defy her parents to see what actually happens.

The people of the UK ultimately voted to defy the Government of the day. They called the political elite’s bluff and decided emphatically not to take heed of the ‘experts’ who predicted financial meltdown in the event of a Leave vote.

What can we, as insight practitioners, learn from this saga? Behavioural economics must take centre stage. Traditional political polling based on system 2 thinking alone has had its day.

Implicit Association Tests and similar tools must be more widely used in opinion based surveys to ascertain disconnect between rational and irrational public sentiment, to better identify paradoxes and subtle nuances often not picked up by the media and group-think journalism.

Decision making hierarchies – whether it’s which party to vote for in an election, Remain or Brexit, through to what to buy in the supermarket – are becoming more irrational, as the role of heuristics changes in our social media age.

Now, more than ever before, to ensure the survival, credibility and essentially legitimacy of market research, we have to get to grips with new decision making practices. Let Brexit and the false assumptions made as to how people would actually vote be a key lesson for our whole industry, not just the political classes.

Adele Gritten is managing director of key accounts at Future Thinking


6 years ago | 1 like

A very interesting article. Some persuasive analysis too. The behavioural economics approach makes a lot of sense, as the arguments on each side tended to reduce to subjective probability as to the outcome one way or another. Combined with good qualitative research, I suspect that this could have yielded a better prediction of the outcome. I do wonder, however, why commentators seem, so far, to have failed to acknowledge that there may well have been a proportion of 'Leave' voters (perhaps considerable) who considered carefully the rarely-mentioned issue of democracy, in which (much as one might love European countries) Britain has secured, over a few hundred years, a pretty good system, while the EU appears likely to drift into government by civil servants. Dificult to research careful thinkers, of course...

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5 years ago | 1 like

Leave won the referendum, but cognitive biases would have been at play for those who voted remain too. Interestingly, the so-called experts did get it wrong with their predictions of an immediate recession, but that's hardly surprising since economic forecasting has such a poor track record. We should also wonder at the cognitive bias which makes some people take economic forecasts more seriously than is deserved.

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