It has been suggested that egotistical attributions for success and failure are mediated by the affective reactions resulting from achievement outcomes. To establish the motivational impact of failure-related affect on subsequent ego-defensive attributions, an excitation transfer paradigm was used to manipulate the negative feelings elicited by failure. After working on a social skill test, 33 male subjects engaged in a physical exercise task. Failure feedback on the test performance was given either one, five, or nine minutes after exercise. Compared to the nine-minute control condition, more defensive attributions were found in the five-minute condition, and somewhat less defensive attributions were found in the one-minute condition. Excitation transfer theory implies that the displeasure elicited by the negative feedback is enhanced in the five-minute condition and underestimated in the one-minute condition. Results offer support for the notion that outcome-related affect motivates egotistical causal attributions. The individual, having a pervasive need to view himself positively, experiences success and failure as affectively significant events. (Author/NRB)