AI Tutor
Imagine a classmate slams their locker door shut, kicks their backpack, and storms down the hall without saying a word. Do you immediately think, "What a mean person," or do you wonder, "Did they just get terrible news?"
Whenever you ask why someone acted a certain way, you are making an attribution — a mental judgment about the cause of a person's behavior.
How do our brains decide whether to blame someone's personality or the situation around them?

Heider's Two Buckets

In 1958, Austrian psychologist Fritz Heider observed that everyday people act like "naive scientists," constantly piecing together clues to predict and explain human behavior.
Heider discovered that we sort every explanation into one of two categories: an internal attribution (also called a dispositional attribution) or an external attribution (a situational attribution).
An internal attribution points to something inside the person, like their personality traits, intelligence, mood, or effort. An external attribution points to factors outside the person, like peer pressure, luck, task difficulty, or the physical environment.
Sorting causes into internal or external sounds simple enough, but how does your brain collect evidence to pick the right one?

Kelley's Covariation Model

In 1967, social psychologist Harold Kelley formalized Heider's idea into a logical framework known as the covariation model. He noted that for something to cause a behavior, that factor must be present when the behavior happens and absent when it doesn't.
Kelley showed that observers evaluate three specific types of information before arriving at an attribution: consensus, distinctiveness, and consistency.
Consensus asks: do other people act the same way in this exact situation? If everyone laughs at the comedian, consensus is high; if only one person laughs, consensus is low.