Sharon is smiling. According to Harold Kelley, you are likely to attribute her smiling to an external cause (instead of an internal cause) if

A) Sharon smiles the same amount in all situations.
B) you know that you would not smile in the same situation yourself.
C) Sharon smiles more than most other people you know.
D) Sharon smiles at some people but not at others.

External Cause

Factors that originate from outside an individual that can influence or trigger a particular outcome or effect.

Harold Kelley

A psychologist best known for his contributions to social psychology, particularly in the areas of attribution theory and interpersonal relations.

Internal Cause

An explanation of behavior as stemming from personal dispositions, traits, abilities, or feelings.