Past work has shown adolescents and young adults to be notoriously difficult to engage in health promotion initiatives, largely as a result of their low levels of perceived health risk. Therefore, innovative ways of communicating the relevance and importance of health behaviours are needed if we are to motivate young people towards action. One approach to attracting initial participation with this age group may be through the use of incentives (i.e., as a means of supporting attendance at the sessions aimed at developing initial volitional engagement in health behaviours). Past work has shown that incentives such as the provision of free groceries, cash payments, reduced-price healthy vending machine options, and food coupons are effective in promoting healthy eating in adults [
32]. With young people, direct financial incentives have also been found to be effective in promoting both research response rates [
33], and enrolment in health education counselling [
34]. Incentives are particularly powerful in engaging individuals with low economic resources [
35], which may suggest that they would have stronger effects in populations such as school leavers who are likely to be earning low wages. More work in this area is called for, as while empirical work has shown some promise in promoting positive outcomes, effect sizes have so far been small [
32]. Further, the efficacy of incentives in supporting or “priming” behaviour change specifically in young adults, and the efficacy of incentives beyond cash payments have received little research attention.
There is further tension between the use of incentives and recommendations for the promotion of autonomous motivation from the perspective of SDT [
36,
37]. Without an informational component, incentives can undermine intrinsic motivation for existing activities as a person’s attention shifts to the controlling external factors, and they no longer perceive themselves to be acting for the inherent qualities of the activity (e.g., for enjoyment, pleasure, and satisfaction). In this scenario, when incentives are removed it is likely that the behaviour will also cease [
38]. Nonetheless, extrinsic factors can be powerful motivators in the short-term, as many pro-social human behaviours are learned from a starting point of external prompts e.g., the adoption of societal values; [
17]. Thus, it is possible that incentives could represent a motivational prompt for the adoption of a new behaviour. In order for the behaviour to persist a person would need to develop more autonomous motivation over time, so that they become decreasingly prompted by the incentive, and increasingly prompted by appreciating other personally meaningful benefits of the activity though the process of internalization; [
39]. The aims of the present intervention would therefore be to use incentives to provide the initial impetus to prompt attendance at a health promotion programme, but once enrolled, focus on helping participants to develop more autonomous reasons for engagement [
39]. Such an approach is justified as it is unlikely that adolescents would be purely intrinsically motivated towards fitness-oriented physical activity and healthy dietary choices. To minimise the risks of the incentives undermining autonomous motivation, consistent with previous work with young people [
33,
34], the incentives were made contingent on attendance at leisure centre appointments and not on performance or achievement of healthy behaviours (i.e., not matched to key target behaviours). Given recent government attention on the use of incentives for promoting health behaviours e.g., as presented in; [
40], which departs from a theoretical perspective, formally testing the efficacy and outcomes of this approach in an applied setting is important.