Gratitude interventions are known to increase subjective wellbeing. However, it has also been suggested that not everyone experiences equivalent benefits of engaging with gratitude activities, and there have been calls to better understand the moderators of such effects. In Study 1, we explored the effects of writing a gratitude letter, relative to a neutral letter, on changes in positive and negative affect, and observed that the effect of gratitude writing on positive affect was exacerbated in participants with elevated life satisfaction. Study 2 sought to replicate the findings of Study 1 whilst minimising demand characteristics, but failed to observe the moderating effect of life satisfaction. In Study 3, we sought to investigate whether these mixed findings could be explained by demand characteristics. We observed that priming participants with information about the benefits of expressing gratitude ameliorated the effect of gratitude writing on positive affect, but life satisfaction did not moderate this priming effect. On the basis of the findings from these three studies, we conclude that life satisfaction does not moderate the effect of gratitude writing on positive affect, but further work should be undertaken to better understand the conditions under which gratitude writing is most effective. Further, we suggest that demand characteristics are an important consideration for both researchers and interventionists delivering gratitude interventions.
Smith et al. (2026) studied this question.