This paper reports on part of an investigation of the effect computers may have on student motivation. It compares two types of motivation feedback (bad luck and low effort) when they are delivered by two different sources (computer and human tutor). Students who received either type of motivation feedback persisted far more than students who received no feedback, and students whose failures were attributed to bad luck persisted more than those whose failures were attributed to low effort. Students' expectation of success with the next problem significantly predicted their persistence. The study suggests that deflecting the burden for failure away from the student and onto bad luck may be better at motivating students to persist when failures might threaten their sense of self-worth. This is equally true when humans and computers deliver the motivation feedback.