The Person and the Situation

by Lee Ross

To be sure, we would be able to predict very accurately the average level of shyness, aggression, or the like, that each child would manifest over a great many new observations. Indeed, we would be able to predict accurately each child’s entire distribution of responses. That is, we could predict confidently that each child’s distribution of future responses would closely resemble that child’s distribution of past responses. But we still would not be able to reduce by much our uncertainty about individual children’s behavior in individual situations. Specifically, knowing each child’s long-term mean or “true score” for aggression, and making individual predictions accordingly, would allow us to reduce the average discrepancy between what we predicted and what we observed by only about 8 percent. That is, our average error would be 8 percent smaller than if we simply guessed that each child’s behavior in each situation would correspond to the class average.

Contra peronalisism in a nutshell.