A hand selects the one red apple among many green applesBias is a tendency to favor one explanation, opinion, or understanding over another perspective that is potentially equally valid.

What Is Bias?

Everyone operates with some degree of bias, and it can greatly color how we see the world. Several studies, for example, have documented that people are much more likely to accept information that comports with their worldview than information that undermines it.

There are numerous types of biases, a few of which include:

  • Confirmation bias: The tendency to notice information that supports one’s beliefs and ignore information that does not. For example, a researcher who believes women aren’t as strong as men might not use studies that highlight women’s strength or might explain information differently than a researcher who has no bias.
  • Political and religious biases: Biases in favor of political or religious beliefs. For example, a person who believes that God answers prayers is unlikely to abandon this belief even when their prayers are not answered.
  • Heuristics: Heuristics are cognitive shortcuts for understanding the world, and these can create bias. For example, a person might have a heuristic that creates a vision for a stereotypical woman and may then tend to see all women in light of this stereotype, even when they meet women that defy the stereotype.
  • Selection bias: A tendency in scientific research to select study subjects who are not part of the general population or who confirm a researcher’s biases. For example, a researcher who believes that men are less verbal than women might choose men who are less verbal than average.

Bias in Psychology

Bias in psychological research can undermine the progression of knowledge and alter treatment recommendations for mental health conditions. In a therapeutic setting, a therapist’s individual biases might alter the recommendations they make to clients or influence their understanding of a person’s problems. Recognizing one’s own biases is often the first step to eliminating them, because this allows a researcher the opportunity to actively correct for their own biases. Double-blind studies and peer review can also help to counteract the biases of individual researchers.

One example of bias in research is observer bias, which occurs when researchers alter the outcome of a study. This process is not typically deliberate and involves extremely subtle changes both in the way researchers interact with subjects in the study and in what observers choose to see.

When researchers with observer bias interact with subjects, they may subtly alter the outcome of their research. A teacher studying differences in math skills between boys and girls, for instance, might spend more time teaching boys because they believe boys are better at math. This, in turn, would make it more likely for the boys to learn math more effectively and could alter the outcome of the study. Subtle prejudices can also influence the conclusions the teacher draws. The teacher might, for example, notice girls studying very hard and outperforming boys. Rather than concluding that math skills are correlated with time spent studying, the teacher might argue girls are worse than boys at math because they have to spend more time studying.

The most effective way to avoid observer bias is to use double blind studies, where neither the researcher nor the subjects know what is being studied. This, however, is often impossible in psychological research. Researchers who are aware of their biases going into an experiment and who make efforts to correct these biases may avoid some of them. When researchers do not have a financial investment in a particular outcome, they are also less likely to be biased.

Many researchers have claimed observer bias has contributed to differences in behavior and performance between races and genders in scientific studies. Ape language studies have also been roundly criticized because the people teaching apes sign language are also typically the people testing performance, and therefore have a vested interest in the outcome of the research.

Cognitive Biases

A cognitive bias is a mode of thinking that distorts reality in some way, often with the result of clouding a person’s judgements, responses, and thought processes. A couple common cognitive biases include negativity bias and self-serving bias.

Negativity bias

A negativity bias is a cognitive bias that contributes to the tendency to notice and dwell on negative information while neglecting positive information.

Negativity bias can affect decisions, emotions, and even the ability to take in information. Several studies have shown people may attend more readily to negative information. Thus, a person is more likely to notice a car wreck on the side of the freeway than a person helping someone fix a flat tire on the other side of the road. Negativity bias also helps explain why people tend to be more bothered by criticism than they are flattered by compliments and why people tend to dwell more on mean gestures than they relish in kind ones.

Researchers have not identified conclusively why the negativity bias exists. While some researchers argue that the negativity bias is an innate mechanism, others emphasize the primacy of cultural norms in increasing the likelihood that people notice negative information. Some potential reasons for the negativity bias include:

  • Negative information tends to be more novel and jarring. A loud car wreck is much more likely to get your attention than, for example, the silent assistance one person provides to another.
  • Taking in negative information–particularly negative information about threatening scenarios–is critical for survival, health, and social interactions.
  • People tend to more readily remember negative information than positive information. Thus the negativity bias could be a product of memory processing rather than cognitive functions that occur at the moment a person takes in information.

The implications of the negativity bias for mental health are clear and striking. Rumination–the process of lingering on information–over negative information can increase the likelihood that a person develops depression. People who do not notice positive stimuli or who tend to talk about negative occurrences more readily than positive ones are more likely to struggle with unhappiness, depression, and anxiety. A person’s negativity bias can partially be a product of personality and deliberate thought retraining, and people who do not have a strong negativity bias tend to be happier, better-adjusted, and more well-liked.

Self-serving bias

A self-serving bias is a cognitive bias that causes a person to view their own actions favorably or interpret events in a way that is beneficial to themselves. It typically occurs when a person attributes their successes to their own abilities, but any failures to external causes.

An example of self-serving bias can be found in a student who attributes a good grade on a test to their intelligence, but attributes a bad grade to an unfair test, to illness, or to insufficient preparation. In doing so, they are able to take credit for their successes while evading blame for failures.

At its extreme, a self-serving bias can make it nearly impossible for a person to take responsibility for their actions. The constant presence of a self-serving bias might indicate a personality disorder such as narcissism.

However, this bias is also a normal part of human thinking, and most people engage in a self-serving bias at one time or another. The self-serving bias serves several useful functions, including:

  • Preserving self-esteem and helping people maintain a sense of competence, independence, and efficacy
  • Enabling people to take career, educational, and interpersonal risks without bearing the entire brunt of failure

Researchers have long puzzled over apparent differences in mathematical ability between girls and boys. Despite outperforming boys for most of their school years, girls take fewer math classes and are less likely to believe they are good at math. An inversion of the self-serving bias may be to blame. Some studies have found that girls tend to attribute mathematical successes to hard work and mathematical failures to incompetence. Boys, conversely, may engage in a self-serving bias and attribute successes to intelligence and failures to external factors. Boys also tend to overestimate their mathematical competence. This real-life example of a self-serving bias demonstrates how the bias can actually improve performance by encouraging boys to remain in challenging math classes.

Implicit Association Test

The Implicit Attitudes Test aims to measure implicit negative attitudes toward minority groups. It has been used to measure racism, sexism, homophobia, and other forms of prejudice.

One of the most well-known versions of this test is the black-white race IAT. The test shows participants faces and words one at a time. They are asked to categorize the faces as black or white and the words as good or bad using the ‘e’ and ‘i’ keys on the keyboard. In some stages, participants are asked to “match” words and faces by identifying them with the same key. If a person is slow to match black faces with good words or quick to match them with bad words, the test indicates that person may have an implicit bias against black people.

Some critics of IAT say the test is ineffective for measuring prejudice because the results don’t always correlate with explicit bias. Between 2009 and 2015, four separate meta-analyses found IAT results to be a weak predictor of a person’s behavior. A 2017 meta-analysis found that while an individual’s implicit bias could be changed, the altered IAT scores rarely correlated with behavioral changes. In other words, acts of discrimination may involve more conscious thought than previously assumed.


  1. Cherry, K. (2019, May 7). How cognitive biases influence how you think and act. Retrieved from
  2. Colman, A. M. (2006). Oxford dictionary of psychology. New York, NY: Oxford University Press.
  3. Fine, C. (2010). Delusions of gender: How our minds, society, and neurosexism create difference. New York, NY: W. W. Norton.
  4. Goldhill, H. (2017, December 3). The world is relying on a flaws psychological test to fight racism. Quartz. Retrieved from
  5. Hanson, R. (2011, November 17). Confronting the negativity bias. The Huffington Post. Retrieved from
  6. Negativity bias. (n.d.). The Skeptic’s Dictionary. Retrieved from
  7. Nolen-Hoeksema, S. (2000). The role of rumination in depressive disorders and mixed anxiety/depressive symptoms. Journal of Abnormal Psychology, 109(3), 504-511. doi: 10.1037//0021-843X.109.3.504
  8. Panucci, C. J., & Wilkins, E. G. (2011, August 1). Identifying and avoiding bias in research. Plastic and Reconstructive Surgery, 126(2), 619-625. doi: 10.1097/PRS.0b013e3181de24bc
  9. STOP bias. (n.d.). Retrieved from
  10. United States Department of Justice. (n.d.). Understanding bias: A resource guide. Retrieved from

Last Updated: 05-16-2019

  • Leave a Comment
  • patrick

    January 12th, 2017 at 5:40 PM

    I believe i am the victim of an unethical therapist. I, until recently lived with my fiance at her home for four years. Everything was fine, then just after Christmas, i was asked to leave immediately without any reason, which i did. Her daughter lives downstairs, a single mom with her two children, a boy 12, and a girl 14. we were always good to each other and there was never any serious issues, although i tended to joke around a lot, which is my personality, and sometimes got carried away to the point of an apology or two. The daughter is seeing a therapist once a week, and has been for a long time because of a molestation that occurred when she was approximately four, and the man was my fiance’s boyfriend. Her fourteen year old daughter has her own issues requiring some form of medication, however i always treated her with kindness and positive reinforcement. The boy is well adjusted enough, and we would play catch sometimes because he is so much into sports. I had some run ins with the 14 year old such as her presenting herself to me half naked, when no one was around, laying on the floor and spreading her legs, then closing them, calling it a “rug angel,” but i knew not to pay any obvious attention to it, and chocked it up to teens pushing their boundaries. My fiance and i were having some issues that we were working through, but it came as a complete surprise to me when she, her daughter and her new boyfriend, along with one of my fiance’s friends came in and told me i had to leave that night, so i did without question as the new boyfriend looked like he wanted a reason to belt me one. Later, i found that the daughter, under the suggestion of her therapist, record everything i said to her so that she, the therapist could inform her as to whether i was harmful or a threat to her family. I am docile, and never did i ever see this form of therapy where people around the patient were diagnosed simply by listening to brief excerpts from hand picked recordings! i am lost without my love, and we still will see each other, but the daughter forbids me on the property, and is denying her mother any happiness.

  • carefreebear

    April 22nd, 2017 at 1:11 PM

    Oh wow that sounds unthinkable. Like for one I don’t it was right for her to record you in the first place and it is even more surprising that her therapist would suggest such a thing. Do you think the daughter had any sort of resentment towards you at all before all this had happened?

  • Michael

    June 14th, 2017 at 9:30 AM

    I feel i am the victim of bias therapy me and my girlfriend of 9 years saw therapist we are an interacial couple with two kids and first the lady was seeing my girlfriend then she saw us together an the therapist seemligy was taking her side would not let me finish a statement and for the most part ignored what i said and defended my girlfriend and basically mocked me i feel i should report her what should i do and i found myself more defending myself then anything else

  • Jess

    December 18th, 2019 at 7:07 PM

    Self-serving bias is I think, unfortunately, a big problem in therapy. We’ve kind of built a system where if the client recovers, it’s because of the skill and intervention of the therapist. However if the client worsens or doesn’t improve, then often the client’s lack of effort or motivation is blamed for the failure. That way the therapist (and therapy as a whole) retains the idea that their treatment was effective, it’s just that the client wouldn’t accept it. Unfortunately it’s one that ultimately harms clients – not only harming individual clients, but blocking useful inquiry into why some people don’t benefit. If the therapist gets credit for success but the client blame for failure, therapy cannot help but be effective.

  • Lisa

    May 27th, 2020 at 6:53 PM

    Being with positive people can make us feel high

  • janet

    May 14th, 2021 at 12:09 PM

    As a child my wife has been subject to parental abuse and neglect. she was made to carry drugs into state penitentiaries by her mother as a child. We both grew up by the coast. I am from seaside, CA. and she is from Marina, CA. I would say maybe ten to fifteen blocks from the beaches and within distance to Monterey and Carmel area California Vanessa was working and doing ok had A RELIABLE VEHICLE AND HER OWN APARTMENT. just graduated the police academy.
    She got re acquainted with a guy from high school and they became close. He asked her to a party and she agreed. She was drugged taken from a house party sold into a sex trafficking She slowly tells me things but its going to kill her if she can’t find the right treatment. She cuts herself and has made attempts on her life. She cant sleep for longer then about an hour she wakes up scared or in tears fighting for her life.
    I suggest she seek counselling and took her the Monterey Community Hospital Mental Health facility. . I took her there three hours away because I knew that she would get the best of the best care there. They even said they weren’t qualified to deal with this kind of trauma, and they have some of the best doctors and psychiatrists there are. So we came Back to Merced and their behavior health program, as a temporary solution until some one there would help find her the inpatient help she desperately needs. The facility here should be sued in my opinion they allowed my wife to be poached and pair her up with a NAACP, African American rights ,BLM, Christian counselor, family therapist with no trauma experience at all in treating her issues, person from seaside. The person that agreed to counsel her in my opinion is not qualified. we are two hours from our home town and two counties away ( Monterey to Merced) yet the person this county of Merced behavioral service has allowed to jump in, at her own request, has strong ties to the families that did this this to her. This therapist, R. has worked in seaside and Marina as an outreach worker. Was raised in seaside, attended seaside high. The same HS as my wife. She works in an office that is run by an old member of the Black Panther Party. She is a Christian counselor and is active in the churches. My self I was born and raised in seaside and I know all to well what its like growing up in a predominately black town. I was harassed assaulted all kinds of things. I also know every one knows each other. Or one of their family members. So to say R. didn’t know what she was doing would be a lie. This woman should have never been allowed to even talk to my wife. She didn’t do any real therapeutic things, or what I would call therapeutic. Like writing or reading or calling other people or places. There was no reaching out or networking of any kind. Yet this woman had my girl on the line three days a week wanting her to talk about it. V was going thru her trauma with nowhere to put what she was opening. She was hospitalized because it was all too much too fast long story short i have to been thru mental health because of aa rape. so i was trying to ease her pain by suggesting things i was told to do. like write a letter to the people that hurt you read it and burn it. if a variety of other expression and release techniques. well she wrote the letter then sent it. that wasn’t the plan but she felt like she needed to be hears. so the police from the town came to interview her. as soon as she started talking to the police her counselor stopped her and said she could no longer work with her conflict of interest. that she knew the people involved. i knew that was the case from the beginning. she was just using my wife to see what she knew. come to find out she is a fraud in my opinion, i did a little research on this woman and she has multiple address in multiple stated and in some of her paperwork and advertising herself she claims to be Caucasian woman. both of her brother have pages of felonies and were down south around the time my girl was taken. this f#%^&#@ B!tC4 knows the people directly involved. needless to say my girl tripped out started hurting herself I called the medics R. told them where to take her. i called and called for three-day just asking that lady to just let me know where they took her. she never even answered not only me but my wife tried it call her from the hospital, she just cut her off but a week before my wife signed the papers to let ne talk with her about her care, because R. called me a couple time’s to let me know my wife was on the way home. because of the way things happened . the medics just taking my wife and I had no idea where i was sent into a tailspin and sat here crying for three days contemplating taking my own lif. i have been hospitalized for multiple suicide attempts already. i was so close to giving up. this bitch did this to us, and she did it intentionally. she knows we are a lesbian couple, that’s not the Christian way. and we are white , that’s not her practice, why did she even bother , because she had motive,

  • thea

    October 31st, 2022 at 3:01 PM

    You should have reported the counselor to the board of ethics and they would of decided if it was ethical or not. you should of really reported that.

  • Linda

    May 7th, 2023 at 2:21 AM

    I have a friend in marriage counseling and the therapists always side with her (abusive) husband! He somehow cons them into sympathizing with him! This seems to me to be unprofessionalism at its worst! Should I encourage my friend to report any therapist who shows bias in spite of being conned??

  • Anna

    July 6th, 2023 at 12:37 PM

    This same thing happened to me. I did not know who to call back then, but yes, I would call the Board of Ethics on this counselor. They will at least look into it.

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