The augmentation principle is the attributional tendency to assign greater influence to a particular cause or rationale of behavior if there are other factors present that normally would produce a different outcome. Internal attributions are augmented (altered) when there are factors that are unexpected and would normally be a constraint. When an action or behavior has limits or constraint on it the individual's motive must be stronger than the constraints or inhibitions present.
For example, you learn that a person just ran a marathon. That in itself is a great feat but you then learn the person had previously had a stroke and had been completely paralyzed the year before. The augmentation principle would present itself and your internal attributions may shift and your perception of the marathon runner would increase from being generally impressed to extreme admiration and awe.