Why Does Everyone Seem to Agree With You? Overestimating How Common Your View Is
By the BrainSnail editorial team. How these articles are written and checked, and how to tell us when one is wrong.
People consistently think their own opinions, preferences and choices are more widespread than they are. The effect is easy to demonstrate, it has several causes, and it distorts political and social judgement in predictable directions.
What the effect is
The false consensus effect is the tendency to overestimate how many other people share one's own beliefs, preferences and behaviours. It was demonstrated in a classic set of studies in which participants were asked whether they would agree to do something mildly embarrassing and then asked what proportion of their peers would agree, with those who said yes estimating higher agreement than those who said no, and both groups cannot be right. The effect appears across opinions, consumer choices, moral judgements and estimates of how common a behaviour is, and it is robust across many replications, which is worth noting in a field where robustness cannot be assumed. The size varies considerably by domain and is larger for opinions than for factual matters.
Why it happens
Several mechanisms contribute and they are not mutually exclusive:
- •Selective exposure, since people spend time with others like themselves and sample a skewed population
- •Motivated reasoning, since believing one's view is common supports the belief that it is correct
- •Availability, since one's own reasons are vivid and easy to recall while others' are not
- •Focus on the situation, since a person who sees their own response as demanded by circumstances expects others to respond likewise
- •Ambiguity in how the question itself is understood, with people assuming others read it as they do
- •Simple anchoring on one's own position when no other information is available
The opposite error
A complementary effect runs in the other direction and the two coexist. People overestimate how distinctive their abilities and desirable traits are, believing themselves more skilled, more honest and more unusual in their talents than the distribution allows, which is sometimes called false uniqueness. The pattern is therefore not a general failure to estimate but a specific shape, with opinions and choices assumed to be widely shared and abilities assumed to be rare. Both serve the same end, since a common opinion is a reasonable opinion and a rare ability is an enviable one, which is the motivational account of why the two run in opposite directions. Evidence for that account is mixed, and the purely informational explanations account for a substantial part of both.
What reduces it
Several interventions have been tested and the results are mixed in an instructive way. Simply telling people the effect exists changes estimates very little, which is the usual finding for cognitive biases and is worth stating because debiasing by information is what most people assume works. Presenting actual distributional data corrects estimates substantially while the correction fades, and it works better when the data concerns a specific concrete question than a general characterisation of a group. Direct contact with people holding different views reduces the misperception more durably, which is among the better-supported findings in the area. Asking people to explain how somebody could reasonably hold the opposite view has shown some effect. The one thing that reliably makes it worse is engaging with second-hand characterisations of what the other side thinks rather than with what they say.
Where it does damage
The consequences are visible in several areas. Political misperception is substantial and measurable, with people systematically wrong about how their opponents think and about the proportion of the population holding various views, and the errors are larger among those most engaged with politics, which is the opposite of what an information-deficit explanation predicts. A related and separate phenomenon occurs when almost everyone privately rejects a norm while believing others accept it, which sustains practices nobody actually wants and which has been documented on campus drinking, on segregation-era attitudes and on various workplace conventions. Organisations make decisions on the assumption that customers or colleagues share the decision-maker's preferences. And the effect makes genuine disagreement feel like bad faith, since if most people obviously agree, then those who do not must have some other motive.
The takeaway
People overestimate how widely their own opinions and choices are shared, shown by the classic finding that those who agreed to a request and those who refused both estimated their own choice as the common one. Selective exposure, motivated reasoning and the vividness of one's own reasons all contribute. A complementary effect makes people overestimate how rare their abilities are.