In emotion regulation (ER) research, participants are often trained to use specific strategies in response to emotionally evocative stimuli. Yet theoretical models suggest that people vary significantly in strategy use in everyday life. Which specific strategies people choose to use, and how many, may partially depend on contextual factors like the emotional intensity of the situation. It is thus possible – even likely – that participants spontaneously use uninstructed ER strategies in the laboratory, and that these uninstructed choices may depend on contextual factors like emotional intensity. We report data from four studies in which participants were instructed to use cognitive reappraisal to regulate their emotions in response to pictures, the emotional intensity of which varied across studies. After the picture trials, participants described which and how many strategies they used by way of open-ended responses. Results indicated that while a substantial proportion of participants in all studies described strategies consistent with cognitive reappraisal, a substantial proportion also endorsed uninstructed strategies. Importantly, they did so more often in the context of studies in which they viewed higher-intensity pictures. These findings underscore the importance of considering uninstructed ER choice in instructed paradigms and situational context in all studies of ER.