Dr Lauren Taylor BSc Psychology, Msc Health Psychology, current student in PhD Health Psychology

The aim of the present study was to explore perceptions of the Digital Twin (a three-dimensional digital representation of an anatomical body) on a mobile health application, and the potential mechanisms that are important for behaviour change, with a focus on health and weight management. An explorative and participant-led approach was taken using semi-structured online interviews to explore the experiences of people, in this case non-users and users wanting to independently manage their health. An opportunity sample of forty participants from the United Kingdom (20 who had not used digitally assistive technology and 20 who had) were recruited from social media platforms (22 females and 18 males; mean age was 30). The interviews were transcribed verbatim and analysed using Thematic Analysis. Two main themes were elicited: Initiators of behaviour change (i.e., autonomous choices, social influences, and personalisation) and Barriers to behaviour change (i.e., adverse reactions, weight management norms and negative attitudes). Overall, it was suggested that the Digital Twin should be representative of a user's personalised health information and BMI. These results can inform an intervention designed to use the Digital Twin to initiate and maintain lifestyle behaviour change. It can also develop our understanding of how such technology can be applied as a tool for health management.

Many mobile health (mHealth) application interventions include virtual representations of the self in varying forms, such as agents, or avatars to initiate health behaviour change. This review aimed to determine: (i) which virtual representations are effective in mHealth application interventions, and (ii) whether any studies implemented specific mechanisms (the psychological causes of change) and behaviour change techniques (BCTs) to influence positive behaviour change. Following PRISMA guidelines, a narrative systematic review of empirical studies was conducted from ten different databases (ranging from MEDLINE to Cochrane Library) from inception to December 2021. This included articles reporting a virtual representation of mHealth application intervention, published in English from any time point, which addressed and reported a variety of outcome health behaviours. Information on sample characteristics, study conditions, mechanisms and BCTs, results, and conclusions were extracted. Quality and risk of bias were assessed using the Mixed Methods Appraisal and Cochrane Risk of Bias Tools. Out of the 2,579 original search results, five eligible studies (total participants = 509), with low to moderate quality were included. It was found that customisable virtual representation mHealth interventions were most effective in encouraging behaviour change and app adherence. These interventions included mechanisms such as motivation, feedback, self-image, and BCTs such as goal setting, and self-monitoring. The current evidence suggests that virtual representations in mHealth app interventions may positively influence health behaviour change. However, there is limited evidence available to determine to which these influences are a result of the virtual representations, or the intervention design.