The Similar-To-Me Effect

The Basic Idea

Picture your group of friends. They are likely the same age, same gender, and may even come from the same background as you. Even if we pride ourselves on being inclusive and celebrating diversity, we still tend to surround ourselves with people similar to ourselves. While it is normal to get along with people who have similar experiences, like your basketball teammate or a fellow college alumnus, favoring people similar to you becomes a problem when it leads to discrimination.

The similar-to-me effect is a cognitive bias that explains our tendency to prefer people that look and think like us. We have an affinity towards all things familiar to us, which is why the similar-to-me effect is also known as the affinity bias. While it might seem harmless in principle to associate ourselves with familiar people, the similar-to-me effect can lead to unjust consequences when applied to hiring practices, workplace promotions, and tolerance towards otherness.

A man saying "I can't put my finger on why, but I like these people" in front of three other people

For a clever man, different cultures, different lives, different attitudes, different dreams, different of everything are a good teacher! [However, most people] take the things [they] already know from somebody or something like you.

– Turkish writer Mehmet Murat Ildan1

Theory, meet practice

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Key Terms

In-group bias: Our tendency to give preferential treatment to people in a group we identify ourselves as belonging to.

Ethnocentrism: Our tendency to view the world through our own cultural lens and judge our own culture as superior to others.2

Egocentric bias: Our inability to see things from another perspective which can cause us to ignore people who have different viewpoints to our own.3

Social Identity Theory: A theory which states that a person’s sense of self is based on the groups which they belong to.4

Stereotypes: Preconceived notions we assume about people based on them sharing characteristics with a prototype of people in that group that we hold in our minds.

Heuristics: Mental shortcuts we make based on probabilities.


Our tendency to favor those similar to us is the basis of multiple cognitive biases which have likely shaped much of human interaction throughout history. However, it only established its academic roots in 1906, when political scientist William Sumner first identified that we tend to treat people that we identify as part of our in-group better than people that are outside our group. He believed ethnocentrism, a belief that our own culture is superior to others, was the root of in-group bias. Ethnocentrism and in-group bias were posited as reasons behind atrocious treatment of otherness, as evidenced during World War II and the Holocaust. 5

Later, Polish social psychologist Henri Tajfel developed social identity theory, which suggests that people’s sense of self is strongly formed by their group memberships. Social identity theory states that we show favoritism towards people that are similar to us because similar people help us construct our own sense of self. Those people that we use to construct our sense of self become our ‘in’ group and we tend to align ourselves to these people. Social identity theory explains why we group people into ‘them’ and ‘us’ categories, which can  lead to differential treatment. 4

Stereotypes are another reason behind the similar-to-me effect, which is especially prevalent when it comes to liking people that look similar to us. We tend to make assumptions about   wider personality traits based on our own preconceived ideas about what someone from a similar group might be like. In the 1970s, Two of the founding fathers of behavioral science, Daniel Kahneman and Amos Tversky made one of the biggest contributions to our ideas about stereotypes, with their discovery of the representative heuristic. It showed that we tend to compare people to an existing mental prototype.

When it comes to the similar-to-me effect, this prototype is often our perception of ourselves. For example, if you wear glasses and believe that you are intelligent, when you see someone wearing glasses, you will think that they seem intelligent. Kristy Wallace, CEO of Ellevate Network, a company dedicated to changing business culture and breaking glass ceilings, refers to this tendency as the “mini-me syndrome.” We connect to those similar to us more readily because you can “see yourself in that person, so it lends an aspect of trust,” which makes us think they will succeed in a given task.6

While there has been extensive research behind in-group favoritism and snap judgments, the similar-to-me effect provided another layer to preferential treatment by examining how it plays out in the workplace. In 2003, professor of human resource management and organizational behavior, Greg Sears, investigated whether the similar-to-me effect could impact hiring judgment. Sears questioned whether similarity between an interviewer and interviewee would influence the interviewer’s opinion in a group of 40 male undergraduate students. They found that those interviewers who identified an interviewee as similar to themselves believed that the interviewee was more suitable for the job and reported that they were likely to hire them.7

Other studies have demonstrated interviewer bias is a result of the similar-to-me effect, which can lead to detrimental hiring practices and workplace environments. In 2018, the Workplace Diversity Report found that both men and women praise colleagues of their own gender more often than those of a different gender. 6 If people only recognize the talent of those similar to themselves, offices might begin to look more like sororities and fraternities than inclusive, diverse environments.

One way to combat the similar-to-me effect in the workplace is to have a rotation of diverse managers. According to Debra Sqyres, Chief Client Officer at HR company Namely, in a manager rotation system “managers are intentionally moved to new teams to take on new responsibilities and bring more diversity to those teams.” She also suggests that supervisors check in when conducting performance reviews to ensure that all supervisors are evaluating people in the same way and that reviews aren’t being impacted by the similar-to-me effect.6


Researchers at Penn State University have conducted extensive research into the similar-to-me effect and found that the effect can be triggered by a variety of factors from values, habits, and ideas to demographic variables like age, race, and gender. 8

The similar-to-me effect reveals that we have unconscious biases that lead to differential treatment of others. We are quick to assess people based on stereotypes because we encounter so much information on a daily basis that we must rely on rules-of-thumb to quickly process it and make decisions. Unfortunately, these heuristics are not innocent: they are often the basis behind all forms of discrimination, especially racial and gender discrimination.

In isolated incidents, feeling more connected to people that are similar to us can be harmless. However, favoritism for people like us can make it difficult to understand our differences, which can quickly turn into prejudice. It is similar to the slippery slope from mere patriotism to nationalism. While patriotism refers to pride for your country, nationalism means we identify so much with our own nation that it causes us to exclude or dislike people from other nations.

It isn’t just how we treat others that is impacted by the similar-to-me effect; our own wellbeing is equally affected. If we only surround ourselves with people that have similar opinions to our own, we are much more likely to fall victim to confirmation bias. Confirmation bias describes our tendency to give more weight to evidence that supports our preexisting beliefs. If we rely on this bias, it can lead to a very narrow view of the world. Research has shown that socially diverse groups are more innovative than homogenous groups, as they tend to approach problems with more unique solutions. Interacting with different people forces us to anticipate alternative viewpoints and better prepare our own arguments, which further suggests the similar-to-me effect could be a hindrance to progress and innovation.9


There are few, if any, academic studies which disprove the similar-to-me effect. However, some argue that this cognitive bias is not problematic, but useful. A common positive example of the similar-to-me effect is women helping to empower other women. Women continue to face various inequalities in society, one of which is workplace representation. Therefore, a female manager might purposefully decide to hire another woman to try and right this wrong. They could even become their mentor and help them navigate a male-dominated industry. Since the two women share the same gender and the unjust societal treatment that comes along with it, they can better understand and support one another. It can sometimes be necessary to protect our own, suggesting the similar-to-me effect can have positive connotations depending on the situation.

While the similar-to-me effect sometimes leads to unfair hiring practices, it can also be beneficial to hire someone with a similar personality to you. If you thrive in your work environment, it is likely someone similar to you will as well. Similarities can increase trust, which can be highly beneficial to building an effective workplace environment. Various studies have shown that the greater level of trust between superiors and subordinates, the more productive and satisfied employees are. According to the Leader-Member Exchange theory, managers will give employees in their in-group greater responsibility and set high expectations of them, which leads to personal and professional growth.

The similar-to-me effect can be used to our advantage. Knowing that people show favoritism to those similar to them, relating to people’s interests can help us build trust. For example, if you want to build trust during an interview, try to discuss a shared hobby. According to famous negotiator Chris Voss, mirroring – the art of insinuating similarity – can help create a bond that can be beneficial during negotiations.

Associating with a familiar group has also been shown to lead to greater life satisfaction thanks to increased solidarity. Extensive research shows that we receive the greatest support from people who belong to groups we identify with, which suggests we should return the favor by helping those that are similar to us.10 We might think of various minorities banding together to support each other against racial discrimination.

It is clear that the similar-to-me effect leads to a mixed bag of results. On the one hand, it can lead to solidarity, on the other, it can lead to discrimination. Research shows that the advantages and disadvantages of the similar-to-me effect largely depend on whether it solely leads to positive attitudes towards an in-group, or if it extends beyond that and begins to impact the way that we treat people in an out-group.

Job Satisfaction & The Similar-To-Me Effect

Extensive research has shown that employee satisfaction affects the efficiency and performance of an organization. Happy employees lead to a happy boss because productivity levels increase in a positive work environment.

One factor which can contribute to job satisfaction is whether managers experience the similar-to-me effect with their employees. Typically, managers tend to hire people who exhibit similar biographical and attitudinal characteristics to themselves. However, once a manager leaves, those similarities may not be shared between employees and the new manager. Although hiring similar people has advantages, it can also lead to managers overlooking important factors like experience, hard work, and diversity, which all positively contribute to productivity. As there seem to be both advantages and disadvantages to the similar-to-me effect in the workplace, researchers Ardashir Zahed and Farzad Ardabili examined how it impacted job satisfaction.11

To do this, the researchers gave out surveys to 88 employees in a public organization in Iran. The goal of the surveys was to examine how the similar-to-me effect influenced job satisfaction and organizational trust. Zahed and Ardabili found that employees felt pressured to demonstrate similarities to their superiors, which caused stress, tension, and perceived inequality, all of which led to job dissatisfaction. They found that managers tended to promote employees they have the most in common with, which led to organizational mistrust amongst the other employees who felt that their managers weren’t capable of making the most optimal decision. 11

Shared Knowledge and the Similar-To-Me Effect

We often assume, due to the similar-to-me effect, a manager gives an employee a high evaluation because they feel more comfortable with them and trust them more. While liking an individual because they are similar is one potential reason for unfair employee treatment or evaluation, it could also be because managers have greater knowledge about people who excel in the same areas that they do.

Professor of economics Manuel Bagues and his colleague Maria J. Perez-Villadoniga found that superiors tend to give higher valuations to candidates who excel in the same areas as they do. Being knowledgeable about their own skills and areas of expertise, the superior has more readily available information to assess the candidate. For example, consider if a chemical engineer is evaluating two subordinates’ performance in their specialized field: one whose speciality is also chemical engineering and another whose speciality is mechanical engineering. The supervisor would know far more about chemical engineering, and would therefore be able to easily identify if the chemical engineering subordinate is performing well, but they would be less knowledgeable about how well the mechanical engineer is performing.12

Related TDL Content

One Unconscious Bias Is Keeping Women Out Of Senior Roles 

Historically, men have occupied a greater number of managerial and director positions. According to the similar-to-me effect, people tend to hire those that are similar to them, which leads to male executives tending to promote other men to senior roles. As our writers Melissa Wheeler and Victor Sojo analyze, this phenomenon makes it incredibly difficult for women to gain access into executive and CEO positions. Wheeler and Sojo provide various strategies for combating this bias, as well as methods for ensuring equal treatment in the promotion process.

The Role of Thought Confidence in Persuasion

Although confirmation bias suggests that surrounding ourselves with people who think like us could result in a narrow-minded worldview, finding people who share our opinions could also allow us to feel more confident about our ideas. In this article, TDL contributor Zoe Adams explores the benefits of learning that people have similar thoughts to our own, which can validate our good ideas.  Furthermore, Adams explains how this support can build our confidence, and how feeling credible is so important to persuasion.


  1. Similar Quotes. (n.d.). Goodreads. Retrieved June 28, 2021, from
  2. Ethnocentrism. (2016, February 1). Psychology.
  3. The Egocentric Bias: Why It’s Hard to See Things from a Different Perspective. (n.d.). Effectiviology.
  4. Mcleod, S. (2019). Social Identity Theory
  5. In-group bias. (2020, November 24). The Decision Lab.
  6. Grant, G. (2017, August 7). Similar-To-Me Bias: How Gender Affects Workplace Recognition. Forbes.
  7. Similar-To-Me Effect in Employment. (2015, April 17). Penn State Blogg.
  8. Suzuno, M. (2019, April 10). 4 Types of Bias That Can Affect Your Hiring Process. Plum
  9. Phillips, K. W. (2014, October 1). How Diversity Makes Us Smarter. Scientific American.
  10. Group Identification Acts as a Protective Measure. (2021, May 19). The Decision Lab.
  11. Zahed, A., & Sattari Ardabili, F. (2017). Effect of similar-to-me effect on job satisfaction and organizational trust. Problems and Perspectives in Management15(4), 254-262.
  12. Bagues, M. F., & Pérez Villadóniga, M. J. (2008). Why do I like people like me? SSRN Electronic Journal148, 1292-1299.

About the Authors

Dan Pilat's portrait

Dan Pilat

Dan is a Co-Founder and Managing Director at The Decision Lab. He is a bestselling author of Intention - a book he wrote with Wiley on the mindful application of behavioral science in organizations. Dan has a background in organizational decision making, with a BComm in Decision & Information Systems from McGill University. He has worked on enterprise-level behavioral architecture at TD Securities and BMO Capital Markets, where he advised management on the implementation of systems processing billions of dollars per week. Driven by an appetite for the latest in technology, Dan created a course on business intelligence and lectured at McGill University, and has applied behavioral science to topics such as augmented and virtual reality.

Sekoul Krastev's portrait

Dr. Sekoul Krastev

Sekoul is a Co-Founder and Managing Director at The Decision Lab. He is a bestselling author of Intention - a book he wrote with Wiley on the mindful application of behavioral science in organizations. A decision scientist with a PhD in Decision Neuroscience from McGill University, Sekoul's work has been featured in peer-reviewed journals and has been presented at conferences around the world. Sekoul previously advised management on innovation and engagement strategy at The Boston Consulting Group as well as on online media strategy at Google. He has a deep interest in the applications of behavioral science to new technology and has published on these topics in places such as the Huffington Post and Strategy & Business.

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