These results are consistent with the hypothesis that placebo effects in therapeutic contexts are mediated via the affective consequences of performing a motivated ritual.

Eighty participants took part in a 5-day intervention Qi Gong study to enhance well-being and were randomised to either positive or body focus and either high or low hand position. The high hand position improved negative affect and was reported more intrinsically motivating but was unrelated to perceived effort. Positive focus produced better positive affect. For all groups combined, intrinsic motivation and effort predicted all three outcomes. The association between expectancy and perceived benefit was mediated via intrinsic motivation and perceived effort. Results support motivational concordance and positive focus as mechanisms of benefit but not response expectancy.

Common factors play an important role in outcome. Intrinsic enjoyment of a therapeutic treatment is associated with better outcome. Active engagement with a therapeutic treatment improves outcome. Unrealistic expectations about a therapeutic treatment can have a negative impact on outcome.

General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. AbstractObjective: Non-specific factors play an important role in determining benefits from healthpromoting activities. Research findings suggest that individuals are motivated to engage in activities that they expect to be beneficial, which leads to enhanced beneficial outcomes.Previous studies have focussed on beneficial outcomes of motivation during engagement.We investigated whether motivational factors also influence people's decisions to engage with health-promoting activities in the first instance and then subsequently adhere to them. Method:In two studies, participants were informed about a health-promoting activity (Study 1: a breathing exercise for well-being, Study 2: a gratitude exercise for smoking cessation) and told either that it has a "known" or "unknown" effectiveness as a method of influencing their outcome expectancies. Participants were then given the opportunity to engage with the activity over the following days. Participants' intrinsic motivation was also assessed. Results: In both studies, intrinsic motivation positively predicted willingness to engage with the activities as well as subsequent adherence. Describing the gratitude exercise as having a known effectiveness in Study 2 enhanced motivation and adherence to the treatment. Conclusions: Non-specific factors play an important role both in people's willingness to engage with health-promoting activities as well as their subsequent adherence.Our results also show that simple statements about the potential benefits of a health promoting activity can motivate engagement and adherence.

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