Self-Serving Bias: Meaning, Examples and What the Research Shows

By the IQ Revealed Team · Updated November 5, 2026

The self-serving bias is the habit of taking credit for our successes and blaming our failures on something outside us. A good result was down to skill and effort; a bad one was the referee, the economy, the unfair question or bad luck. It is one of the most reliable findings among the cognitive biases: a 2004 review of 266 studies found it in nearly every sample it examined.

Self-serving bias at a glance

What happens: success is explained by internal causes (ability, effort), failure by external ones (luck, the task, other people).
How big: an average effect size of 0.96 across 503 effects in 266 studies, which researchers class as large.
Where it varies: larger in US than in Asian samples, larger in children and older adults, smaller in samples with depression or anxiety.
Why it matters: it blocks learning from mistakes, inflates our share of group work and makes negotiations stall.
The counter: commit to your reasons before the result is known, and judge yourself as you would judge someone else.

What the research found

The idea is old, but the evidence took time to settle. In 1975 Dale Miller and Michael Ross reviewed the early experiments and were sceptical: they found some support for people taking credit for success, but only minimal evidence that people deflect blame for failure. They also argued that the pattern need not be about protecting self-esteem at all: people expect their efforts to succeed, so success feels caused by them and failure feels like an outside surprise.

Later work tipped the balance back towards motivation. Richard Lau and Dan Russell coded newspaper accounts of baseball and football games in 1980 and found that winners pointed to internal causes and losers to external ones in a way that supported a self-enhancement explanation, not the expectancy account. In 1999 W. Keith Campbell and Constantine Sedikides pooled the experiments in a meta-analysis and found that self-threat magnifies the bias: across 14 moderators, from task importance to self-esteem, the conditions that threatened people's self-image produced the larger bias.

The largest synthesis came in 2004, when Amy Mezulis, Lyn Abramson, Janet Hyde and Benjamin Hankin analysed 266 studies yielding 503 independent effect sizes. The average effect size was 0.96, the bias was present in nearly all samples, and its size varied in telling ways:

Culture: about 1.05 in US samples, 0.70 in other Western samples and 0.30 in Asian samples.
Age: children and older adults showed the largest biases.
Mental health: the bias was much weaker in samples with psychopathology (0.48) than in samples without it (1.28), and smallest in samples with depression (0.21), anxiety (0.46) and ADHD (0.55).

Examples of self-serving bias

Couples and teams. In five experiments with discussion groups, married couples, basketball teams and laboratory groups, Michael Ross and Fiore Sicoly found in 1979 that people recalled their own contributions more easily and accepted more responsibility for a joint result than the others gave them.
Negotiations and strikes. Linda Babcock and George Loewenstein reviewed experiments in which each side of a dispute judged what was fair in a way that favoured its own side. The bias caused impasses, came from selective evaluation of the evidence, and showed up in a field study of teachers' unions and school boards in Pennsylvania, where it was linked to strikes.
Company reports. Thomas Keusch, Laury Bollen and Harold Hassink compared the letters to shareholders of Europe's most highly capitalised companies in crisis and non-crisis years and found more self-serving explanations during a crisis, when bad external conditions were available to blame.
Leaders. Joris Lammers and Pascal Burgmer found in three studies that people who feel powerful show a stronger tendency to claim collective successes and to blame collective failures on outside causes.
Voters. Martin Vinæs Larsen found in election surveys and experiments that voters take personal credit when their own finances improve and hold the government responsible when they get worse, which weakens how well elections reward good policy.
Exams and job interviews. The everyday version: the passed exam proves you studied, the failed one proves the questions were unfair.

Self-serving bias vs. the fundamental attribution error

The two are easy to mix up because both are about how we explain outcomes. The fundamental attribution error is about other people: when someone else fails, we tend to blame their character and overlook their situation. The self-serving bias is about ourselves: our successes reflect who we are, our failures reflect the situation. Together they produce a familiar double standard, in which the colleague who missed a deadline is careless while we were overloaded. A related tendency, the Dunning–Kruger effect, describes how people with less skill in an area can overrate their performance, and cognitive dissonance explains why a failure that clashes with our self-image is so uncomfortable to own.

Self-serving bias and intelligence tests

Test results invite the bias. A high score feels like a fair measure of ability; a low one invites explanations about tiredness, noise or a badly written question. Some of those explanations may be true, which is why it is worth knowing how accurate IQ tests are and what can move a score, before the result arrives rather than after. Deciding in advance what would count as a fair test is the same habit that protects against confirmation bias.

How to reduce the self-serving bias

Write your reasons down first. Note why you expect a decision to work before the outcome is known; it is harder to rewrite the story afterwards.
Swap the person. Ask how you would explain the same result if a colleague or rival had produced it.
Split every outcome. For a failure, list what was in your control; for a success, list what was luck or other people's work.
Argue the other side. Babcock and Loewenstein report that impasses can be reduced by debiasing the people bargaining; making the other side's case yourself is one simple way to try.
Ask for a second reading. Someone with no stake in the outcome will usually split credit and blame differently.

Trust and scope notes

This page summarises published research for general information. It is not psychological, medical or legal advice, and the research findings on depression and anxiety describe groups of people, not a way to assess yourself or anyone else. The IQ Revealed test is an online reasoning test of 40 original items for adults aged 18 and over; it does not measure the self-serving bias or any other thinking bias. Our guide to how IQ tests work explains what an online test can and cannot tell you.

IQ Revealed is not affiliated with, endorsed by or connected to the researchers, universities, journals or publishers named on this page. Names are used only to identify the work being described.

Frequently asked questions

What is the self-serving bias?＋

The self-serving bias is the tendency to credit our successes to ourselves, to our ability, effort or judgement, and to blame our failures on things outside us, such as bad luck, a hard task or other people. It is one of the most studied biases in social psychology: a 2004 meta-analysis of 266 studies found it in nearly every sample examined.

What is an example of self-serving bias?＋

A student who passes an exam says it was because they studied hard, but after failing the next one says the questions were unfair. A manager credits a good year to strategy and a bad year to the economy. Researchers have found the same pattern in sports reporting, in married couples' accounts of arguments, in company letters to shareholders and in how voters judge governments.

Why do people have a self-serving bias?＋

There are two main explanations. The motivational one says the bias protects self-esteem, and a 1999 meta-analysis by W. Keith Campbell and Constantine Sedikides found that it grows when people feel their self-image is threatened. The cognitive one, set out by Dale Miller and Michael Ross in 1975, says people expect to succeed, so success feels caused by them while failure feels like a surprise from outside. Both seem to play a part.

Is self-serving bias the same as the fundamental attribution error?＋

No. The fundamental attribution error is about how we explain other people's behaviour: we tend to blame their character and overlook their situation. The self-serving bias is about our own outcomes: we take credit for good ones and look outside ourselves for bad ones. Put together, they can mean judging others harshly and ourselves generously for the same result.

Is the self-serving bias good or bad?＋

Both. A modest positive tilt can help people keep going after setbacks, and Amy Mezulis and colleagues found the bias was weaker in samples with depression or anxiety. But it also makes it harder to learn from mistakes, inflates our share of joint work and, as Linda Babcock and George Loewenstein showed, makes negotiations break down because each side sees its own position as the fair one.

Is the self-serving bias universal?＋

It appears almost everywhere, but its size varies. In the 2004 meta-analysis it was largest in US samples (an effect size of about 1.05), smaller in other Western samples (about 0.70) and much smaller in Asian samples (about 0.30). It was also larger in children and older adults than in other age groups.

How can you reduce self-serving bias?＋

Write down what you expect before an outcome is known, so you cannot rewrite your reasons afterwards. Ask what you would say if someone else had the same result. Look for the part of a failure that was in your control, and the part of a success that was not. Babcock and Loewenstein report that debiasing bargainers made impasses less likely.