The augmenting principle is also known as the augmentation principle. According to psychologydictionary.org, "The augmentation principle refers to whichever is stronger - the will to act with consequences or the will not to act because of the consequences."
The augmenting principle refers to the attributional nature for assigning more importance to a specific behavior or rationale or cause if other factors are available that naturally can generate a different result. Internal attributions are altered (augmented) when unexpected factors are available and can normally become a constraint. The motive of an individual must be stronger than the constraints or limits when the action or behavior has constraints or limits on it.
For instance, you only know that a person ran a marathon. Running a marathon is already an important achievement but you then came to know that s/he had a stroke previously and had been fully paralyzed the year before. According to the augmenting principle, your internal attributions can shift and your idea or perception about the marathon runner will increase from getting normally impressed to extreme awe or admiration.