Introduction Medical training is consistently described as emotionally challenging. Students commonly encounter situations that are likely to trigger emotional reactions, but the influence of emotional reactions to these situations on learning is unclear. This experiment examined the effects of negative emotions on medical residents’ learning of scientific information.

Methods Sixty first-year internal medicine residents (i.e. physicians in training to become specialists) at the São Paulo University Medical School were randomly assigned to watching a video clip either presenting an emotional (experimental group) or a neutral (control group) version of the same situation. Subsequently, all residents studied the same scientific text. Main outcome measurements were learning processes (inferred through study time and cognitive engagement) and outcomes (recall accuracy). Data were analyzed using chi-square and independent t‑tests.

Results The experimental group spent significantly less time (p < 0.001) studying the text and performed significantly worse on the free recall test (p < 0.001) than the control group.

Discussion Negative emotions decreased time invested in a learning task and the amount of knowledge gained from it, possibly because they automatically activated avoidance attitudes or captured part of the residents’ cognitive resources, hindering processing of the learning material. Future studies should further explore the underlying mechanisms of this effect and how it can be diminished.