Self-serving bias
Success is my doing; failure is bad luck or someone else's fault.
What it means
The self-serving bias is the tendency to attribute one's successes to internal, stable causes such as skill or effort while attributing one's failures to external causes such as bad luck or unfair circumstances. Its function is largely protective — it shields self-esteem and sustains a positive self-image — and it can also serve self-presentation, helping people look good to others. The bias distorts learning, because crediting only good outcomes to oneself blocks the honest after-action review that improvement requires. It also fuels conflict: when each party in a dispute or partnership claims credit for joint successes and disowns blame for joint failures, perceived fairness collapses. A notable boundary condition is that the pattern can weaken or invert in depression and in cultures with more interdependent self-construals, suggesting it is not a fixed feature of cognition. It matters because it quietly corrupts performance reviews, post-mortems, and the allocation of responsibility on teams.
Examples
After a good quarter the team takes full credit; after a bad one they blame the market — and never update their strategy.
After a near-miss, drivers say the other car came from nowhere; after a clean motorway run, they credit their own anticipation. The road was the same both times.
A teacher explains strong results by his teaching and weak ones by a difficult intake — so the lesson plan survives every year, learning nothing from either outcome.
First described in Miller & Ross (1975).