In short:

• The literature on the effects of avatars in health care applications is still limited but results are promising.
• In the literature that found positive effects of avatar use on compliance, physical similarity, body size, self-image, customizability, body change and avatar behavior were found to be relevant variables.

Avatars, defined as graphical representations of users in mediated environments, can be applied to a broad range of media technologies. Previous research has shown that avatar has great potential to generate positive psychological and behavioral outcomes in health domains, and thus facilitate success in health interventions¹. There are several theories that can explain the effects of avatar use; social cognitive theory^2,3,4, self-discrepancy theory^5,6 and the general learning model^7,8. In the social cognitive theory the avatar serves as a role model. Learning will be primarily based on imitation. That may be by adopting qualities that are attributed to the avatar, or by behaving in accordance with the self-image that is activated by the avatar^9,10,11,12. In the self-discrepancy theory, the avatar is thought to trigger thoughts about the actual, ideal and ‘ought’ self, facilitating behavioral steps that help to move towards self-improvement¹³ . The general learning model states that learning is strongly dependent on the environment and views the avatar as a modifiable part of that environment. This brief review on the influence of avatars on compliance does not favor any theory and is meant as a broad representation of what is currently known about the effect of avatars on compliance.

Similarity

Compliance to healthier behavior seems to be higher when the avatar shows physical resemblance to the user^3,8. Physical resemblance is thought to generate a sense of connection. This connection can be in the form of identification, embodiment or ‘self-presence’^14,15,16,17. These different types of connection, influence the user experience and, as a consequence, the chosen behavior.

Body size

The physical appearance of the avatar also seems to play a role in compliance. Avatars that have unattainable physical appearances and look like action heroes, do not optimally stimulate compliance. The same results have been found for obese avatars. Studies that compared the effect of different sized avatars, found that avatars with normal physiques were more likely to trigger behavioral changes^18,9,19. These findings seem in accordance with the similarity principle; too big a difference compromises the ability to identify.

Self-domain

Dependent on the user’s self-image, the physical appearance of the avatar may trigger different levels of compliance. If a user has sufficient health cognition, a avatar that looks like the actual self can increase compliance⁶. If a user has a lower level of health cognition, then an avatar that represents the ideal or ‘ought’ self may be more successful^20,21,6,22. In choosing an avatar, it seems helpful to have an understanding of a user’s health cognitions. It’s also relevant to track these cognitions in time, to be able to change the avatar accordingly.

Customizability

Although customizability seems a logical factor in optimizing compliance, it’s hard to make practical assumptions on how and when to customize. Its relationship with compliance still needs to be unraveled in more detail. What has been found is that being able to customize the avatar increases the intention of healthier behavior⁵. This intention however did not lead to detectable behavioral changes. Another interesting and more applicable finding, is that if being healthy is a part of the ideal self, then having an avatar of the opposite sex seems to strengthen the intention to comply to healthy behavior²³.

Body change

Avatars that physically change with the user, are found to have a sex dependent effect on compliance. In men it seems to decrease compliance over time and in women compliance increases^4,24. This phenomenon may be explained by the fact that women are more sensitive to their surroundings than men and thus more motivated to keep up. Men are thought to be more indifferent to this type of stimulus, although that does not fully explain why their motivation seems to deflate. Perhaps it’s the sense of false competition that demotivates them.      

Avatar behavior

Several studies have focused on the influence of avatar behavior and compliance. Although most of them have found interaction effects between the behavior of the avatar and the user, the exact relationship seems complex and intertwined with other variables such as similarity and body size^15,19.

Practical implications

Given the early stages of research in the field of avatars, practical implications must be contoured with caution. Still the research findings so far, in congruence with theories from the field of psychology and sociology, support a few defendable guiding principles for the use of avatars pertaining to user compliance.

• The avatar should be similar to the user, not unfit, customizable and demonstrating health consequences.
• Dependent on the user’s health cognitions, the avatar should reflect the actual, or the ideal or ‘ought’ self.

Literature

1. Fox JA. Avatars for health behavior change. In: Noar SM, Harrington NG, eds. eHealth Applications: Promising Strategies for Behavior Change. New York, NY: Routledge; 2011: pp. 96–109.
2. Ruiz JG, Andrade AD, Anam R, et al. Using anthropomorphic avatars resembling sedentary older individuals as models to enhance self-efficacy and adherence to physical activity: Psychophysiological correlates. Stud Health Technol Inform 2012; 173:405–411. 16.
3. Bandura A. Social cognitive theory. In: Vasta R, ed. Annals of Child Development: Six Theories of Child Development. Greenwich, CT: JAI Press; 1989: pp. 1–60. 17.
4. Fox J, Bailenson JN. Virtual self-modeling: The effects of vicarious reinforcement and identification on exercise behaviors. Media Psychol 2009; 12:1–25
5. Kim Y, Sundar SS. Visualizing ideal self vs. actual self through avatars: Impact on preventive health outcomes. Comput Hum Behav 2012; 28:1356–1364. 27.
6. Jin SA. Self-discrepancy and regulatory fit in avatar-based exergames. Psychol Rep 2012; 111:697–710. 28.
7. Buckley KE, Anderson CA. A theoretical model of the effects and consequences of playing video games. In: Vorderer P, Bryant J, eds. Playing Video Games: Motives, responses, and Consequences. Mahwah, NJ: Lawrence Erlbaum Associates; 2006: pp. 363–378. 30.
8. Kastenmuller A, Greitemeyer T, Fairclough S, et al. Playing exergames and sporting activity: The impact of identification with one’s game character. Soc Psychol 2013; 44: 264–270.
9. Pena J, Kim E. Increasing exergame physical activity through self and opponent avatar appearance. Comput Hum Behav 2014; 41:262–267. 22.
10. Bem DJ. Self-perception theory. Adv Exp Soc Psychol 1972; 6:1–62. 24.
11. Yee N, Bailenson JN, Ducheneaut N. The Proteus effect implications of transformed digital self-representation on online. Commun Res 2009; 36:285–312. 25.
12. Bargh JA, Chartrand TL. The unbearable automaticity of being. Am Psychol 1999; 54:462–479.
13. Higgins ET. Self-discrepancy theory. Psychol Rev 1987; 94:120–121.
14. Looy J, Courtois C, De Vocht M, et al. Player identification in online games: Validation of a scale for measuring identification in MMOGs. Media Psychol 2012; 15: 197–221
15. Fox JA, Bailenson JN, Tricase L. The embodiment of sexualized virtual selves: The Proteus effect and experiences of self-objectification via avatars. Comput Hum Behav 2013; 29:930–938
16. Biocca F. The cyborg’s dilemma: Progressive embodiment in virtual environments. J Comput Mediat Commun 1997; 3:JCMC324.
17. Ratan R. Self-presence, explicated: Body, emotion, and identity extension into the virtual self. In: Lupicini R, ed. Handbook of Research on Technoself: Identity in a Technological Society. Hershey, PA: IGI Global; 2012: pp. 322–33
18. Pena J, Khan S, Alexopoulos C. I am what I see: How avatar and opponent agent body size affects physical activity among men playing exergames: Physical activity in exergames. J Comput Mediat Commun 2016; 21:195–209.
19. Joo YK, Kim K. When you exercise your avatar in a virtual game: The role of avatars’ body shape and behavior in users’ health behavior. Interact Comput 2017; 29:455–466
20. Sah YJ, Ratan R, Sandy Tsai HY, et al. Are you what your avatar eats? health-behavior effects of avatar-manifested self-concept. Media Psychol 2016; 1
21. Kim Y, Sundar SS. Visualizing ideal self vs. actual self through avatars: Impact on preventive health outcomes. Comput Hum Behav 2012; 28:1356–1364.
22. Kuo HC, Lee CC, Chiou WB. The power of the virtual ideal self in weight control: Weight-reduced avatars can enhance the tendency to delay gratification and regulate dietary practices. Cyberpsychol Behav Soc Netw 2016; 19: 80–85.
23. Waddell TF, Sundar SS, Auriemma J. Can customizing an avatar motivate exercise intentions and health behaviors among those with low health ideals? Cyberpsychol Behav Soc Netw 2015; 18:687–690.
24. Fox J, Bailenson J, Binney J. Virtual experiences, physical behaviors: The effect of presence on imitation of an eating avatar. Presence: Teleoperators and Virtual Environments 2009; 18:294–303.

There hasn’t been extensive research on the influence of avatars on therapy adherence yet, but some insights are available. If the avatar resembles an action hero or takes a form that seems unattainable to the user, interest tends to wane. In other words, we are most motivated to engage when our avatar bears some resemblance to us, allowing for a sense of recognition. For some, having an avatar that mirrors their current appearance is helpful, while others prefer an avatar representing their achievable future ‘self.’ To achieve this, the ability to choose and customize the avatar is crucial. Even as our own fitness improves over time, having the avatar reflect similar progress appears to be more impactful for women than men.

From a commercial perspective, scientific research indicates that an avatar can aid in maintaining healthy behaviors, emphasizing the importance of avatar resemblance to the user. Many applications fall short in this aspect, but at Rehablab, we have chosen real-life avatars, ensuring everyone can find one that resonates with them. This identification fosters prolonged adherence to healthy behaviors. Initiating healthy habits might not be the most challenging part, but sustaining them is. Rehablab is here to assist in that journey.