This study examined within-group shifts in the motivation beliefs and regulatory processes of second-year medical students as they engaged in a diagnostic reasoning activity. Using a contextualized assessment methodology called self-regulated learning microanalysis, the authors found that the 71 medical student participants showed statistically significant and relatively robust declines in their self-efficacy beliefs and strategic regulatory processes following negative feedback about their performance on the diagnostic reasoning task. Descriptive statistics revealed that changes in strategic thinking following negative corrective feedback were most characterized by shifts away from task-specific processes (e.g., integration, differentiating diagnoses) to non-task related factors. Implications and areas for future research are presented and discussed.