Do well on a test and you may think:
“I studied hard.”
Do poorly and suddenly the questions were unfair, the room was noisy, and the teacher clearly had a personal grudge against chapter seven.
This tendency is called self-serving bias.
Success fits nicely with a positive self-image
Most people like believing they are capable, competent, and sensible.
When something goes well, connecting the result to your own skill or effort supports that story.
You worked hard.
You made a good choice.
You handled it well.
Sometimes all of that is completely true.
Failure creates a less comfortable problem
A poor result threatens the positive story.
One way to protect it is to emphasize outside causes.
The instructions were unclear.
The timing was bad.
The economy changed.
The other person did not cooperate.
Again, those explanations may be true.
The bias appears when the pattern consistently moves in only one direction.
Why would the brain protect self-esteem?
Confidence is useful.
People who believe they can improve or succeed are often more willing to keep trying.
A little self-protection can prevent one bad result from becoming a complete collapse in confidence.
What is the downside?
Learning requires accurate feedback.
If every success proves you are talented and every failure belongs to somebody else, there is very little room to identify what you personally should change.
The bias can protect self-esteem at the cost of improvement.
Does self-serving bias affect groups too?
Yes.
Teams, companies, and even entire communities can take credit for good outcomes while blaming outsiders for bad ones.
The basic pattern scales surprisingly well.
How can you check yourself?
Use the same standards in both directions.
If effort deserves credit for success, ask whether effort also contributed to failure.
If circumstances explain failure, ask whether favorable circumstances helped success too.
Confidence is useful.
So is occasionally admitting that chapter seven was not the problem.
A related piece of human behavior appears in Why do we blame personality instead of the situation?, where the brain handles another everyday judgment or response.
And that’s the short explanation.
Related explanations: Why do we blame personality instead of the situation?, Why do people think they are better than average?, and Why do we notice evidence that agrees with what we believe?