Explaining Why People Act
Every day we act as amateur scientists of behavior, asking why someone did what they did. Attribution theory studies how we assign causes. Broadly, we attribute a behavior either to something about the person (a dispositional or internal cause — their personality, character, ability) or to something about the situation (a situational or external cause — circumstances, pressure, luck).
The trouble is that we do this with a systematic slant. The fundamental attribution error (FAE) is our tendency, when explaining other people's behavior, to overestimate dispositional causes and underestimate situational ones. The driver who cut you off is "a reckless jerk" (disposition) — rarely "someone rushing a sick child to hospital" (situation).
Strikingly, the bias flips when we explain ourselves. The actor–observer bias is that we attribute our own behavior more to the situation ("I was late because traffic was terrible") but others' behavior to disposition ("they were late because they're irresponsible"). And a further twist, the self-serving bias, leads us to claim credit for our successes (disposition: "I'm skilled") while blaming failures on circumstances (situation: "the exam was unfair").
| Bias | We explain... | ...by favoring |
|---|---|---|
| Fundamental attribution error | others' behavior | disposition |
| Actor–observer bias | our own behavior | situation |
| Self-serving bias | our own outcomes | success = us, failure = circumstance |
Common pitfall: thinking the fundamental attribution error means we always favor dispositional explanations for everyone. It specifically describes how we explain others' behavior. For our own behavior the tendency reverses (the actor–observer bias) — we grant ourselves the situational excuses we deny to others.
A split panel: the SAME late-arrival event explained twice — for "them," an arrow points to a disposition label ("irresponsible"); for "me," an arrow points to a situation label ("traffic").