A stranger walking in front of you trips. You assume this is because he is clumsy, rather than considering the fact that the sidewalk might be uneven. You have just committed .

Fundamental Attribution error

Explanation: The Fundamental Attribution Error can be explained as the tendency to overemphasize or overestimate an observed behavior in a person while underestimating or under emphasizing situational, conditional or environmental conditions or circumstances which might have led or triggered such observed behavior in the individual.

In the scenario above, once the stranger trips and the assumption is that he is clumsy, that is overestimating the observed behavior while underestimating situational condition such as understandingeven sidewalk which might have caused the stranger to trip.