Why do we overestimate agreement?


False Consensus Effect

, explained.

What is the False Consensus Effect?

The false consensus effect describes how individuals frequently overestimate how much others share their beliefs, values, and behaviors. This implies that people often project their personal attitudes and ideas onto others, assuming they are more common or widespread than they actually are.2

Where this bias occurs

Imagine you are a fitness enthusiast who works out daily and maintains a strict, healthy diet. Over time, you've noticed that you feel better and more energetic. You start believing everyone should adopt a similar lifestyle to reap the same benefits. You assume that most people are interested in regular exercise and healthy eating, just like you. 

So, at your next family gathering, you decide to open up the topic and discuss your newfound discovery. But, surprisingly, not everyone is as enthusiastic about it as you are. Some family members prefer a more relaxed way of life, while others have different hobbies and interests. Shockingly, they don't share the same commitment to fitness and nutrition. You are taken aback to discover that your perception about the general consensus on fitness and health was incorrect.

This personal anecdote exemplifies the false consensus effect in action. The bias led you to mistakenly believe that your dream lifestyle of squats and smoothies would be accepted by all. But instead, it highlights how easy it is to project our own behaviors onto society at large.

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Individual effects

Thanks to the false consensus effect, we frequently assume that our personal opinions are more widely accepted by others than they actually are. This cognitive bias can significantly impact our social perceptions and interactions, primarily by fostering a sense of overconfidence in our viewpoints.

For instance, if one strongly supports a particular political ideology, they may incorrectly assume that most of their peers, colleagues, or community members share the same political leanings. This presumption can lead to a distorted perception of reality in which the individual sees their belief as the “norm” rather than their own personal stance.

The false consensus effect can also lead to a lack of understanding or empathy towards those with opposing opinions. If we believe our views are widely accepted, we may struggle to understand why someone would hold a contrasting viewpoint, leading to potential conflicts or misunderstandings.

This bias may also influence decision-making processes. Individuals may make decisions based on what they believe is the consensus rather than considering a full range of options and perspectives. For example, a parent may decide to enroll their child in football rather than trying out other sports, assuming that football is universally loved by children because it's popular in the neighborhood. This decision may not take their child's unique interests or abilities into account, potentially leading to a lack of enthusiasm or engagement in the sport.

The false consensus effect, frequently reinforced by social conformity and lack of exposure to differing viewpoints, can lead to a cycle of rigidity and narrow-mindedness, ultimately hindering personal growth and the ability to adapt to the world’s diverse and ever-changing landscape.

Systemic effects

The false consensus effect can have profound systemic effects both on an individual and societal level. It can lead to self-affirmation and validation, as individuals perceive their beliefs and behaviors as typical or exemplary, bolstering their self-esteem. This perceived social validation can create a heightened sense of self-worth, but can also lead to an overestimation of one's abilities, potentially leading to complacency and blind spots in personal development.

Zooming out, the false consensus effect can have more complex and potentially harmful implications. For example, it can create echo chambers, particularly in online spaces. People may choose to interact primarily with those who share their views, reinforcing their existing beliefs and leading to a lack of diversity in thought. This can hinder societal progress, reducing the chance for innovative ideas to emerge and for constructive dialogue to occur.

While the false consensus effect can significantly impact decision-making processes, it also  exerts influence in behavioral economics. Consider a marketing manager who, blinded by passion for their strategies and products, assumes everyone else is as well. They launch a niche product expecting high demand, only to discover that the general customer base doesn’t share the same interest.  This is a prime example of how the false consensus effect can skew perceptions and outcomes in the business world.

How it affects product

The false consensus effect can significantly influence the product design and development process. For instance, imagine a tech start-up creating a new app. The designers, all tech-savvy millennials, might assume that everyone shares their comfort with navigating complex digital interfaces. As a result, they design a sophisticated app filled with advanced features. However, they fail to consider the general user base which is not as tech-oriented, and ends up finding the app overly complicated. The product's usability is compromised due to the false consensus effect, leading to poor market reception.

To avoid such misalignment, product designers should actively seek and incorporate feedback from a diverse range of potential users – through market research, user testing, and surveys. By understanding and designing for the actual needs of their target demographic, rather than relying on personal assumptions, designers can create products that resonate better with the intended audience, making them more likely to succeed in the market.

The false consensus effect and AI

AI systems learn from big datasets, often reflecting the values and beliefs of their creators. Because creators frequently assume that their values are widely shared, they may overlook or exclude data that represents different points of view, leading to a false consensus effect in the data. In turn, these systems might assume that the majority shares the same opinions as the data they have been trained on and can result in biased or skewed outcomes.

For instance, if a hiring algorithm is trained mainly on successful applications of male candidates, it might develop a bias towards male applicants, wrongly assuming a consensus that men are better suited for specific roles. This skewed approach fosters the false notion that males are inherently more qualified, while simultaneously promoting gender inequity in the workplace. This demonstrates how AI might mimic the false consensus effect, resulting in biassed and unjust conclusions.

With this in mind, it is crucial to ensure diversity in training data and auditing AI systems for potential biases. By removing AI's false consensus impact, we can achieve greater equality and diverse outcomes. It enables AI to judge us based on merit rather than preconceived notions. This results in fairer hiring procedures, more innovative problem-solving, and systems that better reflect the diversity of the larger community, ultimately improving the benefits that AI offers. 

Why it happens

There are three main reasons why the false consensus effect occurs: cognitive simplicity, social comparison, and self-enhancement.

Cognitive Simplicity

It's cognitively simpler and more efficient to project our beliefs onto others rather than investing time and energy into understanding each person’s unique perspective. This cognitive shortcut is related to the heuristic principle, where individuals make decisions based on quick, effortless processes that do not involve thoughtful analysis. This principle was explained further by psychologists Tversky and Kahneman, who suggested that heuristics reduce the mental effort required to make decisions.3 While it is okay to rely on heuristics sometimes, it can inhibit us from engaging in logical decision-making, leading to potentially biased conclusions.

Social Comparison

According to Festinger's social comparison theory, people determine their personal worth based on how they compare to others.4 As such, people tend to surround themselves with others who share similar beliefs and attitudes, creating a perceived consensus. This echo chamber can reinforce existing beliefs and contribute to the false consensus effect, as our perception of what is “normal” or “common” becomes skewed.


People often desire to validate their beliefs and behaviors, which can lead to overestimating the extent to which others share these beliefs. This can be seen as a form of self-affirmation, a concept coined by Claude Steele.5 By believing that our views are widely held, we boost our self-esteem and affirm our self-worth.

While the false consensus bias fulfills individual psychological needs, being aware of it is critical for maintaining a realistic perspective on the diversity of human ideas and behaviors.

Why it is important

The false consensus effect is important because it impacts how we perceive and interact with the world. The overestimation of how much others agree with our beliefs may boost self-esteem, and this effect is further amplified in group settings. This erroneous perception can create an echo chamber, reinforcing our beliefs while potentially blinding us to alternative viewpoints.

This bias can also help us understand conflict. Consider a heated office argument in which one team member believes their idea is the most popular. When the vote results in a split decision, the individual is not only surprised, but also dismissive of opposing viewpoints, further dividing the team and preventing a consensus that values multiple perspectives. This demonstrates how bias can interfere with teamwork and joint decisions. It is important to recognize and reduce this so that we can work effectively as a team and incorporate everyone's ideas.

For decision-makers, the stakes of the false consensus effect are especially high. It can cause leaders to overestimate the support for their ideas, ultimately affecting the success of their decisions. Imagine a manager rolling out a new workflow, presuming team approval. When the team resists, the workflow fails, and productivity dips. This scenario underscores the need for leaders to seek genuine feedback before making decisions.

Lastly, the bias skews our view of what's “normal” in society. By assuming our beliefs are widely shared, we may inaccurately gauge social consensus, leading to potential misjudgements. For example, if a person exclusively watches news from one perspective, they may believe that most people agree with that position, which can come as a surprise when they encounter a different, more diverse collection of viewpoints in the larger community.

How to avoid it

You can avoid the false-consensus effect by practicing some common techniques.

Practice self-awareness

To tackle the false consensus effect, practice self-awareness and self-questioning. Recognize that your point of view is not universal, but rather one among many. For example, you may feel that pineapple is an unpopular pizza topping because you and your friends dislike it. However, by exploring wider taste preferences in different groups, you may discover a range of perspectives, demonstrating that your immediate circle's tastes do not represent that of the larger community. This realization can cause you to consider perspectives unique from your own.

Seek diverse opinions

Engage in conversations with people who hold different views from you. This could be through face-to-face discussions, online forums, or social media platforms. Listening to a wide range of voices can help you escape the echo chamber of your own beliefs.

Seek real-world data

Instead of assuming that others share your views or preferences, seek hard data to confirm or refute these assumptions. This can involve looking at reviews, social media trends, or articles to improve your knowledge. The use of data aids helps in making more objective decisions to counter the subjective nature of this bias.

Lastly, don’t forget to practice empathy. By putting yourself into other people’s shoes, you can gain insight into what they think and challenge your own assumptions.

How it all started

The false consensus effect finds its roots in social psychology, with the term first coined by Ross, Greene, and House in their landmark study in 1977.1 Their research aimed to explore the extent to which individuals overestimate the level at which others share their behaviors and beliefs and was conducted to understand subjective validation, a bias where people consider their opinions as more common than they actually are.

In this study, researchers distributed questionnaires that detailed hypothetical scenarios. Subjects were instructed to select the best option from a selection of options for the situation.  

The results consistently showed that individuals tended to overestimate the prevalence of their responses, leading to the confirmation of the false consensus effect. This ground-breaking research laid the foundation for subsequent studies into various cognitive biases that influence our perceptions of reality.

The discovery of the false consensus effect has sparked a flurry of new research into how humans perceive social norms and make decisions. It's had an impact on conformity, self-esteem, and social comparison theories, resulting in an improved understanding of the human psyche. Ultimately, the false consensus bias has become an essential guide in explaining how we relate to and understand the world around us.

Example 1 - False consensus effect in American politics

One striking example of the false consensus effect in American politics occurred during the 2016 Presidential election. The majority of mainstream media, political pundits, and pollsters predicted a sweeping victory for Hillary Clinton. The consensus was so strong that it shaped the discourse leading up to election day. The assumption was that since they, the media and political elites, perceived Donald Trump's rhetoric as unpalatable, the rest of the American public must surely feel the same way.

However, on election day, the results painted a different picture. Donald Trump emerged victorious in the electoral college, securing the presidency, leaving many in shock. This miscalculation can be attributed to the false consensus effect, where the media and political pundits overestimated the extent to which the wider public shared their beliefs and opinions. They incorrectly assumed that their aversion to Trump's style and policies was a universal sentiment, leading to a severe underestimation of his support base.

This instance demonstrates how the false consensus effect can influence political discourse and decision-making. It reminds us of the danger of assuming that our beliefs, attitudes, and values are more widely shared than they actually are, which can result in significant miscalculations and misjudgements. In this case, it led to unexpected political outcomes that continue to shape American politics and discourse.

Example 2 - The false consensus effect in social media

A striking illustration of the false consensus effect emerged in social media during the “Ice Bucket Challenge” in 2014. This viral campaign involved people pouring an ice water bucket over their heads to raise awareness for Amyotrophic Lateral Sclerosis (ALS). As the challenge gained traction, it seemed everyone was participating and supporting the cause. Many participants assumed that since their immediate circle was involved, the general public must be as enthusiastic and supportive of the cause.

This perception, however, was not entirely accurate. While the campaign successfully raised a significant amount of money, a survey conducted by YouGov US showed that only about 3-4% of U.S. adults participated in the challenge.6 What appeared to be a universal consensus was indeed a false consensus, constructed primarily by the immediate social circles of the participants and the algorithms of social media platforms, which are designed to show users content similar to what they've interacted with or shown interest in.

Despite leveraging the false consensus effect, the Ice Bucket Challenge harnessed this cognitive bias positively. By capitalizing on the enthusiasm that was widely shared, it encouraged more people to participate, amplifying the campaign’s success for ALS awareness.


What it is

The false consensus effect refers to individuals' tendency to overvalue the prevalence of their own beliefs, values, and behaviors. It suggests that people often project their personal attitudes onto others, assuming these perspectives are more widespread than they truly are.

Why it happens

The false consensus effect is influenced by three primary factors: cognitive simplicity, social comparison, and self-enhancement. 

Cognitive simplicity simplifies decision-making processes by projecting one's beliefs onto others. Social comparison leads to perceived consensus as individuals align with like-minded people, creating “echo chambers.”  Lastly, self-enhancement, linked to the concept of self-affirmation, is the overestimation of shared beliefs to validate personal views and boost self-esteem.

Example 1 – False consensus effect in American politics

In the 2016 U.S. election, many experts thought Hillary Clinton would win because they didn't like Donald Trump and thought everyone felt the same. They were wrong; Trump won, and it surprised many people. This shows that thinking everyone agrees with you can lead to big mistakes and misled assumptions.

Example 2 – The false consensus effect in social media

During the 2014 Ice Bucket Challenge, people thought it was more popular than it was because many around them were doing it. However, a survey found that only 3-4% of U.S. adults actually took part. This shows how our friends and what we see online can make us believe something is more common than it is. 

How to avoid it

To avoid the false consensus effect, one can employ four strategies. Firstly, self-awareness and self-questioning can help recognize the subjectivity of personal viewpoints. Secondly, actively seeking diverse opinions aids in breaking out of one's echo chamber. Thirdly, using empirical data can give a more objective perspective and challenge assumptions. Finally, practicing empathy can provide insight into different viewpoints and challenge personal biases.

Related TDL Articles

The Spotlight Effect

The spotlight effect is when we think people notice things about us more than they actually do. It’s like the false consensus effect because both involve overestimating the extent to which our actions and beliefs are shared by others. Curious about the Spotlight Effect? Read this article to find out more about the spotlight effect, why it happens, and how we can avoid it.


Have you ever noticed how other people's cues can influence what you do or think? That's suggestibility for you. It's a mental shortcut that, like the false consensus bias, can mess with our memories and choices. Curious about how these biases affect your thinking? Explore this article to learn about the impact of suggestibility and how to keep your decisions your own.


  1. Ross, L., Greene, D., & House, P. (1977). The false consensus effect: An egocentric bias in social perception and attribution processes. Journal of Experimental Social Psychology, 13(3), 279–301. https://doi.org/10.1016/0022-1031(77)90049-X
  2. Good, H. (2023, February 7). What is the false consensus effect. Cognitive Biases. Retrieved from https://dovetail.com/research/false-consensus-effect/
  3. Tversky, A., & Kahneman, D. (1974). Judgment under Uncertainty: Heuristics and Biases. Science, New Series, 185(4157), 1124-1131.
  4. Festinger, L. (1954). A Theory of Social Comparison Processes. Sage Journals, 7(2). https://doi.org/10.1177/001872675400700202 
  5. Steele, C. M. (2008). The Psychology of Self-Affirmation: Sustaining the Integrity of the Self. Science Direct.  https://doi.org/10.1016/S0065-2601(08)60229-4 
  6. Moore, P. (2014, August 22). Poll Results: Ice Bucket Challenge. YouGov/US. https://today.yougov.com/entertainment/articles/10183-poll-results-ice-bucket-challenge 

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The Decision Lab

The Decision Lab

The Decision Lab is a Canadian think-tank dedicated to democratizing behavioral science through research and analysis. We apply behavioral science to create social good in the public and private sectors.

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