Socially-driven persuasive health intervention design: Competition,social comparison,and cooperation

Abstract

Persuasive technologies are tools for motivating behaviour change using persuasive strategies. socially-driven persuasive technologies employ three common socially-oriented persuasive strategies in many health domains: competition, social comparison, and cooperation. Research has shown the possibilities for socially-driven persuasive interventions to backfire by demotivating behaviour, but we lack knowledge about how the interventions could motivate or demotivate behaviours. To close this gap, we studied 1898 participants, specifically Socially-oriented strategies and their comparative effectiveness in socially-driven persuasive health interventions that motivate healthy behaviour change. The results of a thematic analysis of 278 pages of qualitative data reveal important strengths and weaknesses of the individual socially-oriented strategies that could facilitate or hinder their effectiveness at motivating behaviour change. These include their tendency to simplify behaviours and make them fun, challenge people and make them accountable, give a sense of accomplishment and their tendency to jeopardize user’s privacy and relationships, creates unnecessary tension, and reduce self-confidence and self-esteem, and provoke a health disorder and body shaming, respectively. We contribute to the health informatics community by developing 15 design guidelines for operationalizing the strategies in persuasive health intervention to amplify their strengths and overcome their weaknesses.

Introduction

There is growing evidence that persuasive technologies (PTs) are effective tools for motivating behaviour change, influencing people, and promoting learning using various persuasive strategies.^1–3 PTs for health – which are designed as interventions with the primary purpose of changing a user’s behaviour or attitude without using coercion or deception^4,5 – have attracted the attention of researchers, physicians, and health practitioners as a novel approach for motivating desirable health behaviour using various persuasive strategies. Research has shown that PTs can be strategically designed to motivate desirable behaviour change, for example, to help people overcome addictive behaviours such as substance abuse,^6–8 to promote personal wellness, to manage diseases, to engage in preventive behaviours,^5,9,10 and to avoid risky behaviours.^6,7,11,12

A fundamental feature of PT intervention is persuasion, an attempt to influence or reinforce behaviours, attitudes, feelings, or thoughts.^4,13 Persuasion can be achieved using persuasive strategies. Socially-oriented persuasive strategies (competition, social comparison, and cooperation) are the most widely and frequently employed strategies both in persuasive health technologies and other online support interventions because of their ability to leverage social influence to motivate behaviour change. Socially-driven PTs are PTs that employ the socially-oriented strategies, competition, social comparison, and cooperation to motivate behaviour change. Studies have shown that these socially-driven PTs can be effective for motivating health behaviour change. As a result, researchers have applied them for motivating behaviour change across several health domains, including binge drinking prevention,^6–8 drug and substance use prevention, HIV and sexually transmitted disease (STD) prevention and treatment, ¹⁴ smoking cessation,^15,16 being physically active,^17,18 and healthy eating.^19–21 They have also been applied in the area of disease management, including in teaching skills for self-management of type 1 diabetes ²² and asthma. ²³

Despite the wide application of the socially-driven PTs across many persuasive health domains as an intervention, there have been mixed findings regarding their effectiveness at motivating the desired behaviour change. Although there are many stories of successful socially-driven persuasive interventions with respect to their effectiveness at motivating healthy behaviour change,^{19,20,24–26} research has also shown that using socially-driven persuasive intervention as a tool to motivate behaviour change could be counterproductive.^20,27–30 For example, Palinkas et al. ³¹ in their evaluation of a socially-driven intervention for primary and secondary prevention of drug and alcohol use among multiethnic female adolescents found that the intervention was largely ineffective and mainly counterproductive as the prevalence of alcohol and drug use increased significantly over the intervention period.

There is still a gap in knowledge on how and why the socially-oriented strategies (competition, social comparison, and cooperation which are the driving forces of the socially-driven persuasive interventions) could influence behaviour either positively or negatively and the mechanisms through which they motivate or demotivate behaviours. This is essential for effective operationalization of the strategies in intervention design and the success of socially-oriented persuasive health intervention in general.

To advance research in this area, we conducted two large-scale studies of 1108 and 790 (a total of 1898) participants to investigate the strengths and weaknesses of the three socially-oriented strategies (competition, comparison, and cooperation) that are widely used in persuasive health interventions design. We investigated these strategies in the context of PTs for promoting healthy eating behaviour (study 1) and PTs for motivating change in risky health behaviours such as binge drinking (study 2). Investigating two different health domains allows us to uncover a wide range of strengths and weaknesses that could be generalized across other domains. As a secondary objective, we validated the persuasiveness of the strategies and showed their comparative persuasiveness with respect to their ability to motivate healthy behaviour change.

We used prototype persuasive implementation of the individual strategies that has been validated in other studies.^13,32 The results of a thematic analysis of 278 pages of qualitative data reveal important strengths and weaknesses of individual strategies that could facilitate or hinder their effectiveness at motivating desirable behaviour changes. Specifically, we found that because each of the socially-oriented strategies harnesses the principle and the power of social influence to motivate behaviour change, they share some common strengths (such as their tendency to make behaviours fun, exciting, interesting , and appear easier to do than usual) and weaknesses (such as their tendency to be invasive and jeopardize an individual’s privacy and relationships ).

However, because each of the strategies differs in their operationalization of the social influence principle, some strengths and weaknesses are unique to the individual strategies or subsets of the strategies. Some of the strengths are as follows: Competition gives a sense of accomplishment; Comparison allows for subtle and empowering peer pressure ; and Cooperation provides opportunities for mutual support , group encouragement , and reinforcement and offers opportunities to collaborate, make and interact with friends. On the other hand, some of their weaknesses are as follows: Competition could trivialize the importance of healthy behaviour and annoy and discourage people; Comparison and Competition could encourage body shaming and health disorder (e.g. eating disorder) and reduce self-esteem ; Cooperation and Competition could cause unnecessary stress, tension, pressure and make people anxious . This knowledge of the strengths and weaknesses of the strategies will inform not only the choice of the appropriate strategies to employ in a particular PT design but also the manner in which the strategies will be operationalized in PT designs. The operationalization of the strategies can amplify their strengths or their weaknesses.

Our findings also reveal that the three socially-oriented strategies differ significantly with respect to their overall persuasiveness, with the social comparison being the most persuasive of the strategies.

Our findings advance existing knowledge in the area of persuasive health intervention design by offering five main contributions. First, we provide insights into the mechanism through which socially-driven persuasive health interventions could motivate or demotivate health behaviours by revealing the strengths and weaknesses of the individual strategies that should be taken into account by PT for health designers when employing each of the strategies. Second, we provide a comparative analysis of the mechanism through which the three strategies could influence behaviour positively and negatively by comparing and mapping the strengths and weaknesses of individual strategies. Third, based on our findings, we offer 15 design guidelines on how to operationalize/implement the strategies in persuasive health intervention design to amplify their strengths and overcome their weaknesses. Fourth, we validate and compare the perceived effectiveness of individual socially-oriented strategies and show that they differ significantly in their overall persuasiveness via a large-scale study. Finally, we provide an extensive review of existing socially-driven persuasive health interventions (classifying them into interventions for health promotion and prevention and interventions for disease management). We also deconstruct how existing interventions operationalized the three socially-oriented strategies.

These contributions build on and extend our previous work ³³ where we only reported a few of the strengths and weaknesses and six design recommendations based on a preliminary analysis. Besides, this study is based on a larger data set of 1898 participants and an in-depth analysis of 278 pages of qualitative data which allows us to uncover more details and provide more insights, 15 design guidelines, and extensive discussions of design implication for persuasive health intervention by situating them within the context of existing knowledge.

Related work

In this section, we present a brief overview of socially-oriented persuasive strategies and socially-driven persuasive health interventions employing the strategies.

Socially-oriented persuasive strategies

A fundamental feature of PT intervention is persuasion, an attempt to influence or reinforce behaviours, attitudes, feelings, or thoughts.^4,13 Persuasion is often achieved using various persuasive strategies. Persuasive strategies are techniques that can be used in PT intervention design to promote desirable behaviours or attitudes. ³² Over the past few decades, a number of persuasive strategies have been developed. For example, Fogg ⁴ developed seven persuasive strategies, and Oinas-Kukkonen and Harjumaa ³⁴ built on Fogg’s strategies to develop 28 persuasive system design strategies.

Among all the strategies, socially-oriented persuasive strategies (competition, social comparison, and cooperation adopted from Oinas-Kukkonen and Fogg^4,34) have been widely employed in PT intervention for health designs and other online health support systems.^3,32,35 The major distinction between socially-oriented strategies and other persuasive strategies is their ability to leverage the power of social influence to motivate behaviour change. ³⁴

Social influence is a term used to explain the effect that other people have on us – our behaviours, beliefs, and attitudes. ³⁶ Social influence occurs when an individual’s behaviour or attitude is affected by others. Almost all our behaviours can be shaped by the power of social influence. According to Berger, ³⁷ ‘without our realizing it, other people’s behaviours have a huge influence on everything we do at every moment of our lives, from the mundane to the momentous occasion. Even strangers have a startling impact on our judgments and decisions’. As a result, research has applied the principle of social impact to influence behaviours in many domains including marketing, ³⁸ education, ³⁹ transportation, ⁴⁰ environmental sustainability, ⁴¹ energy and water conservation,^42,43 and of course health.^17,18 For a typical example of an application of social influence principle in the marketing domain, see Amazon.com. ³⁸ Amazon.com employed the power of social influence in their e-commerce website to motivate customers to purchase products and hence increase sales using the customers who bought this also bought that concept and the product rating tactics. Similarly, in the area of energy conservation, Gustafsson and Svahn ⁴² described a mobile application called Power Explorer which allows teenagers to compete with their peers on who used the less energy as a way of saving energy. With respect to education, Christy and Fox ³⁹ investigated the impact of social influence on students’ educational performances using a leader board which allows the students to view and compare their performance with that of others. In the health domain, Toscos et al. ¹⁷ developed a mobile health application that leverages the power of social influence to motivate teenage girls to exercise by comparing their activity levels. This is in contrast with the Fish ‘n’ Step ¹⁸ which employed the self-monitoring strategy to motivate physical activity by allowing users to track their own behaviours.

Considering this increasing application of social influence principle to affect individual’s behaviours in various domains, recent research efforts have focused on developing systematic approaches for operationalizing the principle in various application domains. In the field of PTs, Oinas-Kukkonen ⁴⁴ proposed three socially-oriented strategies – competition, social comparison, and cooperation:

• Competition strategy provides opportunities for users to compete with one another while performing the behaviour as a way of motivating the desired behaviour.

• Social Comparison strategy offers users the opportunity to view and compare their behaviour performance data with that of other user(s). However, comparison strategy does not involve winning or losing, and it does not involve an obvious and direct interaction with others (peer groups), differentiating it from the competition.

• Cooperation strategy offers an opportunity for people to collaborate (work together) to achieve a shared behaviour objective and applaud them for achieving their goals together.

For a detailed discussion of these strategies, see the work by Oinas-Kukkonen and Harjumaa. ³⁴

Among all the domains of applications, the use of socially-driven PTs (which employ these strategies) in the health domain has received special attention,^45,46 likely due to the importance of maintaining good health and wellness. Therefore, this study will focus on socially-driven PTs for health and wellness with special emphasis on socially-driven PTs for promoting healthy eating and socially-driven PTs for motivating change in risky health behaviour (risky alcohol behaviour change).

Socially-driven persuasive health interventions

PTs aim to bring about desirable change in attitude and/or behaviour without using coercion or deception. ⁴ Socially-driven PTs are PTs that employ the power of social influence (via the three socially-oriented strategies: competition, comparison, and cooperation) to motivate behaviour change. Studies have shown that these socially-driven PTs can be effective for motivating desirable behaviour change.^15–21,47 As a result, researchers have employed these strategies in persuasive health technologies for motivating behaviour change in many health domains, including binge drinking prevention,^6–8 drug and substance use prevention,^6,31,48 HIV and STD prevention and treatment, ¹⁴ smoking cessation,^15,16 being physically active,^17,18 and healthy eating.^19–21,49

In general, socially-driven persuasive health technologies can broadly be categorized into two main areas: socially-driven persuasive health technologies for health promotion and prevention and socially-driven persuasive health technologies for disease management.

Socially-driven persuasive health interventions for health promotion and prevention

Preventive health behaviours are behaviours that are undertaken to prevent sicknesses, detect early signs of sickness, and maintain general health and well-being. ⁵⁰ Examples include smoking cessation,^15,16 being physically active,^17,18 healthy eating,^19–21 and binge drinking prevention.^6–8 Several socially-driven PTs have been developed for health promotion and prevention.

For example, National Mindless Eating Challenge (NMEC) is a mobile phone–based persuasive health intervention aimed at promoting healthy eating behaviour. ²¹ NMEC employs the social comparison strategy to motivate behaviour change. NMEC users are required to care for virtual pets or plants and that entails them following some healthy eating recommendations. At the beginning of the application, users are assigned tasks that are relevant to their healthy eating goals and are given the opportunity to view and compare their performance with the performance of others (social comparison). Similarly, LunchTime is a persuasive application for motivating healthy eating. ¹⁹ LunchTime employs the competition and comparison strategies to motivate behaviour change. Users assume the roles of restaurant customers, and their goals are to choose the healthiest food from a list of food choices. Each user is allowed to compare his or her performance with that of other users (competition and comparison). Finally, RightWay Café is a game-based persuasive health intervention that employs competition to promote healthy eating and physical activity. ⁵¹ At the beginning of the game, the users create a personified avatar using their own personal characteristics, such as height, gender, body frame, name, physical activity, weight, and age. Users are tasked with managing the daily activity of their avatar (such as calorie consumption and physical activity) to enable them to reach a healthy weight. The user who is most successful at managing his or her avatar’s daily diet and physical activity in a healthy way wins (competition).

Typical examples of socially-driven persuasive intervention in the area of physical activity are NEAT-o-Games, ⁵² Phone Row, ⁵³ Fish ‘n’ Step, ⁵⁴ and Chick Clique. ¹⁷ NEAT-o-Games ⁵² is a persuasive game-based intervention that employed competition and comparison to promote physical activity. The virtual racing game requires users to race with other users in their mobile network. The user’s physical activity (monitored using wearable accelerometers) is used as input to control the speed of his or her avatar in the race. At the end of every day, players’ activity points are compared and winners are announced (competition and comparison). Similarly, NEAT-o-Games and Phone Row ⁵³ employed the competition and comparison to motivate moderate intensity physical activity by requiring users to control the movement of a smartphone racing boat using their body movement. Users compete and compare their performance with the performance of other users (competition and comparison). Fish ‘n’ Step, ⁵⁴ employs competition and cooperation to promote physical activity. A user’s daily step count is associated with the growth and flourishing of a virtual fish in a tank. A user’s fish tank includes other users’ fish, thereby fostering both cooperation and competition. Users could compete with one another (competition) as an individual or as part of a team (cooperation) and are provided feedback regarding their calories burned, personal progress, and ranking. Chick Clique ¹⁷ is a persuasive mobile health application that leverages competition and comparison strategies to motivate teenage girls to exercise. Chick Clique allows up to four friends to engage in a friendly competition where the group’s walking statistics are tracked, ranked (competition), and compared with the other members (comparison).

Several PTs have also employed the socially-oriented strategies highlighted above to motivate risky health behaviour change. For example, N-Squad Web Adventure ⁸ is a socially-driven PT which employed the cooperation to impart knowledge about the consequences of alcohol consumption and hence discourage risky drinking behaviours. The application simulated the impact of unhealthy alcohol intake on an individual’s body including the circulatory, digestive, and nervous systems. It requires that users work as part of a group to resolve some challenges about risky drinking behaviours embedded in the application (cooperation). Similarly, Thinking Not Drinking: A SODAS City Adventure ⁴⁸ is a game-based persuasive intervention for preventing unhealthy alcohol use. Thinking Not Drinking employs the social comparison to motivate behaviour change. Each game session begins with skill-specific goals that a user must accomplish. The game trains players on how to overcome peer pressure (social comparison) and avoid alcohol abuse. For a review of applications of persuasive strategies to motivate changes in alcohol and other risky health behaviours, see the work by Lehto and Oinas-Kukkonen. ³⁵

Socially-driven persuasive health interventions for disease management

PTs have also been employed to impart disease-specific knowledge and self-management skills on patients. These include educating patients on how to manage certain illnesses, helping them conform to treatment directives by providing relevant health information, providing timely reminders to the patients, simulating health behaviour, and providing opportunities for users to rehearse health behaviours that are related to their specific illness.^32,55 Persuasive interventions for disease management are mainly targeted at people who identified themselves ill and the overarching objective is to help them manage their illness or get well with the aid of the PTs.

For example, Packy and Marlon is a persuasive health intervention that helps children and teenagers self-manage their type 1 diabetes. ²² Users are tasked with keeping their virtual characters’ diabetes under control by monitoring the avatar’s vital body signs, administering insulin, and other drugs as may be necessary. ²² Packy and Marlon simulates various real-life diabetes challenges. To win, each one of the two users, Packy and Marlon, must effectively manage their characters’ diabetes and insulin intake; therefore, they must support each other (cooperation). Similarly, Bronkie the Bronchiasaurus is a persuasive health intervention aimed at imparting asthmatic children with asthma self-management skills. ²³ The persuasive application simulates good and bad real-world asthma self-management skills to impart self-monitoring skills to kids with asthma. The application presents two virtual characters (Bronkie and Trakie), and users are required to help the characters control their asthma. To achieve this, users have to avoid triggers such as dust and smoke that have the tendency of impacting their asthma negatively while they go on their mission. They also need to measure and monitor breath strength, take medications, and use the inhaler as required. The user’s health decisions are determined by the character’s health outcome and a good health outcome is required to win (competition). This review is by no means exhaustive; however, it is a good representation of common practice in the area of socially-driven persuasive health technologies design.

This review shows that the socially-oriented strategies have been widely employed in PTs to motivate behaviour change across various health domains. The evaluated persuasive health interventions reported varying degrees of success at achieving the intended health objectives and mixed findings with respect to the effectiveness of the socially-oriented strategies.^18,21,30,32 However, there is a lack of research into the mechanism through which the strategies could motivate or demotivate behaviours; why they may work in one context and fail in another. Revealing the strengths and weaknesses of the individual strategies would shed light on the mechanism through which these socially-oriented strategies could motivate or demotivate behaviours and suggest ways of operationalizing them to reduce their weaknesses and amplify their strengths. It will also shed light on why many persuasive interventions record varying degrees of success, mixed findings, and even failures. ²⁸ Again, because the socially-oriented persuasive strategies are often employed en masse, there is little knowledge on their comparative efficacy.

Study design and method

In this section, we focus on the purpose of our study, the study instruments, and data collection method which were presented in a previous study. ³³

Purpose

In our study, we set out to address two important issues in persuasive health intervention research: (1) investigation of the perceived persuasiveness of three socially-oriented persuasive strategies (competition, comparison, and cooperation) with respect to their ability to motivate changes in healthy behaviours and (2) investigation of the mechanism through which these three strategies could motivate or demotivate the adoption of healthy behaviours by examining their strengths and weaknesses. Specifically, we focus on two common application domains of persuasive health interventions to ensure uniformity and generalizability. They include (1) PTs for encouraging healthy eating behaviour and (2) PTs for motivating change of risky healthy behaviour (risky alcohol behaviour change).

Measurement instrument

To achieve the aims of our study, we conducted two separate empirical studies. The first study focuses on PTs for motivating healthy eating behaviours, while the second study focuses on PTs for motivating a change of risky alcohol behaviours. To gather the required data for both empirical studies, we used prototype PT implementation of each of the socially-oriented strategies. The study instruments have been validated in previous studies.^13,32 Specifically, in each study, we represented each of the three socially-oriented strategies in different storyboards. In study 1, the storyboards focus on PTs for encouraging healthy eating, while, in study 2, the storyboards focus on PTs for promoting change of risky alcohol behaviours. All of the storyboards were designed by an artist following the recommended storyboard design guidelines proposed by Truong et al. ⁵⁶ Storyboards, in general, provide a common visual language, which individuals from different socio-cultural backgrounds can easily read and understand. ⁵⁷ Moreover, in previous research works,^32,58,59 they have been found to be an effective way of evaluating and depicting persuasive strategies to users of a persuasive intervention to elicit the right responses, which will eventually inform the intervention design. In our studies, the storyboards portray a character, which represents the user (or a study participant), and his or her interactions with simulated PTs for motivating the respective health behaviour change – illustrating the individual socially-oriented strategies. For example, in Figure 1, the user is the character (in blue dress and red hair) interacting with the computer.

Figure 1.

Storyboard illustrating the Competition persuasive strategies in the context of persuasive technology for motivating healthy eating behaviour – adapted from Orji et al. ³²

In designing the study instruments for both of our studies, a number of steps were followed.

First, we evaluated and iteratively refined the storyboards by taking into consideration recommendations from domain experts, with whom we interacted. Upon completing the expert evaluations, we proceeded to carry out the initial online user evaluations with the sole purpose of ensuring that our storyboards accurately depicted the respective strategies. Figure 1 shows an example of a storyboard which illustrates the competition strategy in the context of PT for motivating healthy eating, while Figure 2 shows competition in the context of risky alcohol behaviour change.

Figure 2.

Storyboard illustrating the Competition persuasive strategies in the context of persuasive technology for motivating risky alcohol behaviour change – adapted from Orji et al. ¹³

Second, following each storyboard, we presented to participants a validated scale for assessing the perceived persuasiveness of each socially-oriented persuasive strategy to elicit quantitative feedback on its effectiveness. The scale was adapted from Orji et al. ³² and has been used by a number of studies.^13,60,61 Specifically, we asked participants the following questions:

“Imagine that you are using the system presented in the storyboard above to track your daily eating (or alcohol intake in study 2), on a scale of 1 to 7 (1-Strongly disagree to 7-Strongly agree), to what extent do you agree with the following statements: a) The system would influence me. b) The system would be convincing. c) The system would be personally relevant for me. d) The system would make me reconsider my eating (or alcohol drinking) habits.”

Third, each strategy was followed with an open-ended question. The open-ended questions allow participants to provide qualitative feedback (comments) on the strategy represented in each storyboard and how they would use the persuasive system. Furthermore, the comments allowed them to justify their ratings of each strategy with respect to its effectiveness (i.e. strengths and weaknesses). Prior to assessing the persuasiveness of each strategy, we ensured that the participants understood the strategy illustrated in the storyboard. We achieved this by asking them two comprehension questions. In the first question, we asked the participants to identify the illustrated strategy on the storyboard from a list of strategies (‘What strategy does this storyboard represent?’). In the second question, we asked them to describe what is happening in the storyboard in their own words (‘In your own words, please describe what is happening in this storyboard’). Responses from participants who answered both comprehension questions incorrectly were discarded. Together with the responses from participants who gave correct answers to the two comprehension questions, we also retained responses from participants who answered one of the comprehension questions correctly. Moreover, we asked them questions about their eating and drinking behaviours as well as demographic information.

Data collection

Study 1 was approved by the University of Saskatchewan’s ethics board, while study 2 was approved by the University of Waterloo. Afterwards, we recruited participants for the studies using Amazon Mechanical Turk (AMT): an online recruitment platform, which allows access to a global audience at a relatively low cost and ensures efficient survey distribution and reliable results.^62,63

We used SurveyMonkey to design our questionnaires. To eliminate possible bias due to a fixed ordering of the storyboards, we used the page randomization functionality provided by SurveyMonkey. This randomized the positions of the storyboards (and their associated questions) by varying their ordering for each participant.

Prior to conducting the main study, we carried out two pilot studies. The first pilot study (which focused on healthy eating) consisted of 30 participants (15 were recruited from AMT and 15 from a university in Canada). The second pilot study (which focused on binge drinking behaviour change) comprised 20 participants (10 were recruited from AMT and 10 from a university in Canada). The preliminary evaluation of the pilot studies confirmed the suitability and understandability of our study instruments.

Participants’ demographic information

A total of 1898 valid responses were included in our analysis after filtering out incomplete and incorrect responses to comprehension and attention-determining questions. In all, 1108 of these responses came from study 1 and 790 responses from study 2. In appreciation of their time, participants received US$2 as compensation. Moreover, our participants were at least 18 years of age at the time of data collection; they also read and understood English well. Finally, specifically for study 2, participants were those who consumed alcohol often or had consumed alcohol at least once. In general, we have a relatively diverse population in terms of gender, age, and education level attained (see Table 1). Our sample in each study was relatively diverse, as there were participants from different continents and countries, such as the United States, India, Canada, Mexico, and other countries of the world.

Table 1.

Participants’ demographic information.

Total participants = 1898
Gender	Females (48%), males (52%)
Age	18–25 (31%), 26–35 (39%), 36–45 (18%), over 45 (12%)
Education	Less than high school (1%), high school (30%), college diploma (13%), bachelor’s degree (38%), master’s degree (16%), doctorate degree (1%), others (1%)

Data analysis

The two main aims of this article are as follows: (1) to examine the persuasiveness of the three socially-oriented strategies that are commonly employed in persuasive health intervention design and (2) to investigate the mechanism through which these strategies could motivate or demotivate healthy behaviour by investigating the strengths and weaknesses of the individual strategies. To achieve this, we used several well-known analytical tools and procedures. We summarize the various steps taken to analyse our data in this section:

1. We validated that our storyboards accurately depicted the intended socially-oriented strategy by running the chi-square test. ⁵⁹

2. We ascertained the appropriateness of our data for analysis using the Kaiser–Meyer–Olkin (KMO) sampling adequacies and the Bartlett test of sphericity. ⁶⁴

3. To evaluate and compare the persuasiveness of the socially-oriented strategies, we calculated the average score for each strategy and conducted a repeated measures analysis of variance (RM-ANOVA) followed by pairwise comparison. The analysis was conducted after validating for the ANOVA assumptions.

4. We also used notched box plot to visualize the persuasiveness of the strategies (see Figure 3).

5. To tease out the strengths and weaknesses of the individual socially-oriented persuasive strategies, we conducted a thematic analysis ⁶⁵ of 278 pages of qualitative participants’ comments from our participants about the individual strategies.

Figure 3.

A box plot showing the overall persuasiveness (y-axis) of the strategies on a scale ranging from 1 to 7. The thick horizontal line indicates a neutral rating of 4. The notches represent the 95 per cent confidence interval for each median. The non-overlapping notches (as shown by the dotted red line) give 95 per cent confidence that Comparison differs from Competition and Cooperation.

Storyboard validation

To ensure that participants understood the socially-oriented strategy illustrated in each of the storyboards, we ran chi-square tests on the participants’ responses to the multiple choice questions that asked them to identify the strategy represented in each of the storyboards. The results for all of the three socially-oriented strategies were significant at p < 0.01. This shows that our participants understood the storyboards and that the storyboards effectively illustrated the intended socially-oriented persuasive strategies. ³²

Measurement validation

We determined the suitability of our data for further analysis using the KMO sampling adequacies and the Bartlett’s test of sphericity. Our results showed that the KMO was 0.733, well above the recommended value of 0.6. The Bartlett test of sphericity was statistically significant (χ²(3) = 3148.392, p < 0.0001). These results demonstrate that our data were appropriate for more advanced analysis.^28,32,66

Results

In this section, first, we show and compare the results of the overall persuasiveness of the socially-oriented strategies, which is followed by the results of the thematic analysis of the qualitative data that shows, maps, and compares the strengths and weaknesses of the three strategies.

Comparing the persuasiveness of the strategies overall

The results of the ANOVA show significant main effects of strategy type (F(1.93, 3667.470) = 10.325, p = 0.000) on persuasiveness. This means that overall there are significant differences between the three socially-oriented strategies with respect to their persuasiveness. Generally, social comparison emerged as the most persuasive of all the three strategies (significantly different from Competition and Cooperation as shown by the Bonferroni-corrected pairwise comparisons). Figure 3 shows the notch box plots of the strategies. The notch represents the 95 percent confidence interval of the median. The non-overlapping notches (as shown by the dotted red line) give 95 percent confidence that social comparison differs from competition and cooperation. In general, our participants perceive the three socially-oriented strategies as persuasive, with persuasiveness scores significantly higher than the neutral median rating of 4 (p < 0.0001), indicated by the thick horizontal red line in Figure 3.

Thematic analysis

To tease out the strengths and weaknesses of individual socially-oriented persuasive strategies, we conducted a thematic analysis ⁶⁵ of 278 pages of qualitative comments about the strategies from our participants. Iteratively, we analysed the comments to identify the central themes within them and their relationship until it seemed that no further ideas were emerging from them. We classify the themes into strengths and weaknesses. We report here the themes that transpire from the analysis.

The strengths and weaknesses of socially-oriented strategies

The result of the analysis uncovered 10 major strengths and 8 weaknesses of the socially-oriented strategies. One of the strengths is common to the three strategies: They make health behaviours fun, exciting, interesting , and appear easier to do than usual. The three strategies also share two weaknesses in common: They have the tendency to be invasive and jeopardize an individual’s privacy and relationships and they could backfire and demotivate behaviour by encouraging unhealthy behaviour . Some strengths and weaknesses are unique to the individual strategies or subsets of the strategies. Some unique strengths are as follows: Competition gives a sense of accomplishment; Comparison allows for subtle and empowering peer pressure ; and Cooperation provides opportunities for mutual support , group encouragement , and reinforcement and that it offers opportunities for collaboration, make and interact with friends. On the other hand, some of their weaknesses are as follows: Competition could trivialize the importance of healthy behaviour and annoy and discourage people; Comparison and Competition could encourage body shaming and health disorder (e.g. eating disorder) and reduce self-esteem ; Cooperation and Competition could cause unnecessary stress, tension, pressure and make people anxious .

In this section, we present and compare the strengths and weaknesses of the socially-oriented strategies and their corresponding supporting participants’ comments. We also map each of the strengths and weaknesses and their corresponding comments to the individual socially-oriented strategies – competition, comparison, and cooperation (Table 2 and 3).

Table 2.

The mapping of the strengths of the socially-oriented persuasive strategies with some sample participants’ comments.

Strengths of the socially-oriented strategies (competition, comparison, and cooperation) with sample participants’ comments	CMPT	CMPR	COOP
1. It makes people committed to and focused on the behaviour by giving them more reasons to push towards their health behaviour goals:  - ‘I am highly competitive; this is a good strategy to motivate me and keep me committed’ a . (P51) – CMPT  - ‘Competition is necessary to keep most people interested, focused and pushing towards their goals’. (P1108) – CMPT  - ‘Competition gives people more reason to strive towards a goal they already have’. (P285) – CMPT  - ‘Competition is really helpful when it comes to healthy behaviour like healthy eating and exercising. As odd as it sounds, knowing you have to beat someone helps to keep you working towards a goal. Very motivating!’. (P957) – CMPT  - ‘Wanting to out-do my peers would be great motivation to improve my results’. (P624) – CMPR	✓	✓	X
2. It gives users a sense of accomplishment and achievement:  - ‘Winning gives a great feeling of accomplishment!’. (P80) – CMPT  - ‘Competition gives a sense of accomplishment that motivates most people to continue to do good in their behaviour’. (P115) – CMPT	✓	X	X
3. It engages and challenges people to be better:  - ‘… I could imagine it being a challenge type thing for people like me, … like staying sober for the entire month of October and see who wins’. (P471) – CMPT  - ‘Competition always makes games more engaging’. (P989) – CMPT  - ‘I think this strategy is very powerful. I think it is well known the effects of peer pressure, in this case, in a positive way. Also, it’s been shown that people often learn best in social contexts, and if you have friends who are sharing the same struggles as you are, the motivation provided by comparing with the group and knowing that you are not alone would, I think, be very reinforcing’. (P591) – CMPR	✓	✓	X
4. It makes health behaviours fun, exciting, interesting, and appear easier to do than usual:  - ‘The competition aspect is fun’. (P16) – CMPT  - ‘The competition aspect makes supposed to be boring activity of healthy living exciting’. (P957) – CMPT  - ‘Competition is necessary to keep most people interested, focused and pushing for their goals’. (P511) – CMPT  - ‘The work being put in towards something seems easier when you compete for it’. (P1028) – CMPT  - ‘I like this one even better! Along with comparing myself to my friends, there should be an added incentive of getting bonus points not because I won my friends but because I performed the behaviour. It’s really fun’. (P1269) – CMPR  - ‘When you are working with someone else for a common goal it might be easier to achieve this goal’. (P704) – COOP  - ‘Working together it makes it seem easier or increases the motivation to eat less’. (P307) – COOP	✓	✓	✓
5. It allows for subtle and empowering peer pressure to promote healthy behaviours:  - ‘I would really prefer a subtle comparison with my friends than making it a competition’. (P235) – CMPR  - ‘Strangely enough when the app is indirectly competitive instead of intentionally competitive I’d be much more inclined to use it’. (P758) – CMPR  - ‘There’s a bit of competition, but not a head-to-head kind of competition, will be motivating’. (P1028) – CMPR  - ‘Subtle comparison may override my anxiety for competition’. (P17) – CMPR  - ‘The fact that you would be able to compare your drinking habits with your friends is really impactful’. (P1671) – CMPR	X	✓	X
6. It offers users opportunities to serve as positive role models:  - ‘I like the fact that my friends and I can act as good role models for each other by drinking less and that will trigger a positive response’. (P600) – CMPR  - ‘Up until this point, the most effective option because it allows for positive encouragement’. (P741) – COOP  - ‘I would feel more inclined to work harder if I knew someone else is looking unto me’. (P1548) – COOP	X	✓	✓
7. It provides opportunities for mutual support, group encouragement, and reinforcement:  - ‘This system is good and will get users to encourage each other to meet their goals because they will both benefit’. (P654) – COOP  - ‘This’s most effective option because it allows for positive encouragement’. (P1) – COOP  - ‘Working together with my friends to achieve my goals would motivate me and help me motivate my friend’. (P1204) – COOP  - ‘I like this system more than the others, because I think it could make people support and encourage each other, in order to reach a goal that takes effort on both their parts’. (P957) – COOP  - ‘Friend support is far better than friend competition or comparison when seeking out lifestyle changes’. (P389) – COOP  - ‘I would feel more encouraged because others would depend on me and I wouldn’t want to disappoint them’. (P631) – COOP  - ‘This system is good and will get users to encourage each other to meet their goals because they will both benefit’. (P1514) – COOP  - ‘This is the best strategy! I do not like the idea of competing with friends on an activity such as weight loss. It is something that people should support each other on, not try to better each other’. (P1475) – COOP  - ‘Working with another would make me think I’m not the only one doing it and would be encouraging’. (P13) – COOP  - ‘This is much more psychologically healthful – and helpful – than the other strategies. Friends should celebrate their goals together and encourage each other, not be smug or feel superior’. (P100) – COOP  - ‘This system has the benefit of solidarity’. (P297) – COOP	X	X	✓
8. It provides opportunities for people to stay responsible and accountable to others which propel them to meet their behaviour goals:  - ‘It’s easier to meet goals when you’re held accountable by others or you know others are checking your progress’. (P9) – COOP  - ‘If I could work together with someone I would work harder to control my drinking because I am accountable to someone else, who’s depending on me to achieve a goal’. (P5) – COOP  - ‘I believe that the influence and obligation to a friend would be a very effective and healthy motivator’. (P1608) – COOP  - ‘I like this much better than the competition route. this allows each user to be accountable for not only themselves, but for another. It’s easier to lose weight when you have someone on your team keeping you on track’. (P691) – COOP  - ‘This would make me go all the way to live healthily because I wouldn’t like the other person to think that I am not being responsible with my health’. (P975) – CMPR  - ‘It is easier to meet a goal when you know others are checking your progress’. (P215) – CMPR  - ‘Yes, they will hold you accountable! if you have friends who are sharing the same struggles as you are, the motivation provided by the group would, I think, be very reinforcing’. (P1115) – CMPR	X	✓	✓
9. It raises users’ sensitivity to disappointment and makes them work harder to avoid disappointing other people and themselves:  - ‘It is good; I won’t want others to be disappointed by me. So, it would work well’. (P1661) – COOP  - ‘I wouldn’t want to let the other player down, so I think this sort of game would work well for me’. (P870) – COOP  - ‘You would be more inclined to do well so that you don’t let your partner down’. (P16) – COOP  - ‘By cooperating to meet a common goal the players are less inclined to fail since they are less inclined to let their partner down than they would be to let themselves down’. (P1116) – COOP	X	X	✓
10. It offers users opportunities to collaborate, make, and interact with friends:  - ‘It is very convincing and provides for healthy collaboration and opportunity to interact with friends more often’. (P918) – COOP  - ‘… Instead of inspiring rivalry, this method inspires companionship. Awesome!!’ (P908) –COOP  - ‘The buddying idea is much more powerful than the competition idea’. (P69) – COOP  - ‘This would be good for building and strengthening relationships, too’. (P528) – COOP  - ‘The best of the three systems in my opinion because the more people with the same goal, the more power there is available for achieving that goal in many ways including support and morale boosting for one another the better’. (P651) – COOP  - ‘I like this idea of working with friends rather than working against them’. (P823) – COOP  - ‘Provide an avenue to be happier together by winning together’. (P423) – COOP	X	X	✓

‘✓’ indicates themes belonging to each strategy, ‘X’ shows themes that do not apply to a strategy. CMPT, CMPR, and COOP denote the strategy that a particular comment belongs to the Competition, Comparison, and Cooperation, respectively.

a

Quotes from participants are included verbatim throughout the article, including spelling and grammatical mistakes.

Discussion

In this section, we discuss the design implications of our findings and highlight design opportunities for employing our results to inform the design of socially-driven persuasive health interventions.

Design implications of the findings: socially-oriented strategies

Socially-oriented persuasive strategies (competition, social comparison, and cooperation), which tap into the power of social influence to motivate behaviour change, have been widely employed in PTs designs. So far, research has shown some mixed findings with regard to their effectiveness at motivating behaviour change.^{18,20,27–29,31} Hence, there is a need for researchers and designers to understand their persuasive mechanisms, including their possible strengths and weaknesses, to ensure a more effective operationalization in future PT health interventions.

The common strengths of the socially-oriented strategies

Our findings reveal that the socially-oriented strategies share some common strengths and weaknesses (as a group) as well as some unique strengths and weaknesses (that are specific to the individual strategies). These strengths and weaknesses could facilitate or hinder their effectiveness, respectively.

Specifically, because each of the strategies explores the principle and the power of social influence to motivate behaviour, they share one strength of making behaviours fun, exciting, interesting , and appear easier to perform than usual in common. In addition to the strength shared by the three strategies, the competition and comparison share two other strengths in common:

1. They have the tendency of making people committed to and focused on the behaviour by giving them more reasons to push towards their goals .

2. They engage and challenge one to be better.

These findings suggest that PT health intervention designers could employ either the competition or the comparison strategy in their design to challenge people, keep them committed, engaged, and focused on the task required to achieve a healthy lifestyle. Therefore, we recommend that PT interventions targeting audience who are hindered from adopting healthy behaviour by their lack of commitment, focus, and adequate challenge should employ the competition or comparison to motivate and promote desired health behaviour change .

Similarly, the cooperation and comparison strategies share two additional strengths in common:

1. They offer users opportunities to serve as positive role models .

2. They provide opportunities for people to stay responsible and accountable to others, which propel them to meet their behaviour goals.

These findings suggest that, apart from their tendency to make the process of adopting healthy behaviours fun, exciting, and interesting, the cooperation and comparison strategies also leverage the principle of social consistency. Social consistency builds on people’s tendency to act to create and maintain a positive and consistent public image, to impress and avoid disappointing others. This is a major distinguishing factor between the cooperation and comparison strategies and the competition strategy which tend to emphasize individual win and not accountability to others. Therefore, we recommend that to design for people who are concerned about maintaining a positive public image and serving as positive role models to others by staying responsible and accountable, designers should employ either the cooperation or the comparison strategy . There are several tools available to determine individual’s consciousness towards public image. For example, PT health intervention designers can use the public self-consciousness scale ⁶⁷ to assess individuals’ concern with public image and therefore choose the appropriate persuasive strategies to motivate behaviour in line with their concern with public image.

On the other hand, the cooperation and competition strategies are very distinct with respect to the mechanism through which they motivate behaviour change. They share no additional strengths in common apart from that shared by the three socially-oriented strategies.

The unique strengths of the socially-oriented strategies

With respect to their unique strengths, although each of the strategies explores the principle and the power of social influence to promote healthy behaviour change, they differ in their operationalization of the principle. As a result, there are some unique strengths that are specific to each of the strategies that designers need to take into consideration when employing the individual strategies.

• Competition . The competition strategy has one unique strength that differentiates it from the comparison and cooperation strategies:

This unique strength of the competition strategy could be harnessed in many ways to motivate healthy behaviour change. For example, because of the intangible and long-term oriented nature of the benefit of accomplishing healthy behaviours, many people may not derive a sense of personal accomplishment and immediate gratification directly from performing the health behaviour. According to Hartney, ⁶⁸ lack of the feeling of personal accomplishment could lead people to make negative judgements of their competence and achievements and promote the feeling of insufficiency and low self-esteem and hence easily discouraged.

Adopting healthy behaviour lacks the immediate feeling of what we call healthy behaviour performance accomplishment (coined from Bandura ⁶⁹ ), which could be a major motivator for many people. Employing the competition strategy in PT health interventions has the tendency of filling this gap by providing individuals a sense of accomplishment derived from being able to win (by performing the desired health behaviours). Therefore, we recommend that PT health interventions targeting audience who are discouraged from adopting healthy behaviour by the lack of immediate sense of accomplishment associated with many healthy behaviours, should employ the competition strategy to give the users a sense of accomplishment and motivate behaviour change . As shown by the sample comment, ‘Competition gives a sense of accomplishment that motivates most people to continue to do good in their behaviour’. (P115)

Participatory design approach could be adopted to understand the target audience and what is hindering them from adopting healthy behaviour and hence uncover important behavioural determinants. This would inform PT health intervention designers on the right persuasive strategies to employ to target the identified determinants and motivate behaviour change.

• Social Comparison . The comparison strategy has one unique strength that differentiates it from the competition and cooperation strategies:

The major difference between the comparison and the other two socially-oriented strategies (competition and cooperation) is that comparison often does not involve an obvious and direct interaction with the others (peer group), which often introduces some levels of anxiety, stress, and tension among the users. This is supported by the fact that comparison is the only strategy which does not share in the weakness of causing unnecessary stress, tension, pressure and making people anxious that is inherent in the competition and cooperation strategies as shown in Table 3. This unique strength of the comparison strategy is further supported by the sample participants’ comment in favour of comparison strategy (CMPR) and against competition (CMPT) and cooperation (COOP) strategies:

“Strangely enough, when the app is indirectly competitive instead of intentionally competitive I’d be much more inclined to use it.” (P758) – CMPR

“There’s a bit of competition, but not a head-to-head kind of competition, will be motivating.” (P1028) – CMPR

“This would also embarrass me. I’d be nervous that my friends would think of me as a fatty if I ate more than them often.” (P89) – CMPT

“It can create tension between people and create opportunities for negative criticism.” (P56) – COOP

Table 3.

The mapping of the weaknesses of the socially-oriented persuasive strategies with some sample participants’ comments.

Weaknesses of the socially-oriented strategies (competition, comparison, and cooperation) with sample participants’ comments	CMPT	CMPR	COOP
1. It reduces self-esteem, causes depression, makes people lose confidence in themselves and their ability and feel alienated:  - ‘This could kill someone’s self-esteem if they are struggling with a diet and see all their friends are doing better’. (P911) – CMPT  - ‘Some people like me are not strongly motivated by competition with others since that will affect my self-esteem, therefore I’ll not enjoy any application using this strategy’. (P72) – CMPT  - ‘This application would make me feel not as good as my friends. I would lose my confidence’. (P259) – CMPR  - ‘I think this application would make me feel not as good as my friends. I would lose my confidence’. (P998) – CMPR  - ‘Due to prior addiction, I think shame and depression would kick in more’. (P68) – CMPR  - ‘I think it can be bad for self-esteem in some people’. (P64) – CMPT  - ‘One could alienate heavy drinking partners’. (P18) – CMPR  - ‘When I’m interested in self-improvement, I am not really interested in comparing myself to others or “winning” over them – this would probably just make me feel bad about either myself or for the other person’. (P523) – CMPR	✓	✓	X
2. It causes unnecessary stress, tension, pressure and makes people anxious:  - ‘This would also embarrass me. I’d be nervous that my friends would think of me as a fatty if I ate more than them often’. (P89) – CMPT  - ‘Interesting idea for competitive people, though I think that this would be stressful for me’. (P12) – CMPT  - ‘This strategy would also not be great for me because I would be anxious about other people seeing my score and then feeling better for having beaten me’ (P98) – CMPT.  - ‘It can create tension between people and create opportunities for negative criticism’. (P56) – COOP  - ‘You could fall into the habit of worrying more about what other people are doing. On its face, it doesn’t look like a good model’. (P815) – COOP  - ‘If I did go in with a friend, I would feel more pressure to perform to not let them down. It creates unnecessary tension. Better to pace myself’. (P57) – COOP  - ‘It would be tedious for me to convince someone; I would rather work on my own personal goals’. (P357)–COOP	✓	X	✓
3. It could be invasive and jeopardize an individual’s privacy and relationships:  - ‘People need a supportive, encouraging environment to grow and change within. Competition drives people apart’. (P1056) – CMPT  - ‘Living healthy as a competition is dangerous for a relationship’. (P19) – CMPT  - ‘It seems like my privacy would be compromised’. (P6) – CMPT  - ‘I would be influenced by this system but I don’t like the idea of competing with friends. I think it could create problems with relationships’. (P419) – CMPT
‘Seems a bit invasive to have your performance displayed for all your friends to see. As a comparison method, I would prefer to compare my average overall daily performance, not my friends – keep it private’. (P471) – CMPR - ‘I do not really like the idea of having other people see your personal activity’. (P589) – CMPR - ‘Comparing your own food intake to that of strangers seems like an invasion of privacy’. (P1726) – CMPR - ‘It would not work for me; I’d get upset with my friend if he fails! I may not want to risk my relationship with him’. (P19)–COOP - ‘This may lead to strained relationships. if you feel the other person does not always make a full effort to reach the daily goal, things could get tense’. (P702) – COOP - ‘I like this better, although I may not use it because it seems like an invasion of privacy’. (P78) – COOP - ‘This works for me only if you make all participants anonymous’. (P301) – CMPR - ‘I would not use this app because it is not private. If it does not indicate how many calories your friend ate, but just tells you that you did better or worse than your friend, I think I would like this app better’. (P171)	✓	✓	✓
4. It could backfire and demotivate behaviour by encouraging unhealthy behaviour: - ‘… Points could end up being rewarded for risky behaviours, just because they were better than their friends. That’s wrong. It could backfire’. (P1590) – CMPT - ‘This type of game could go both ways … if I drink less than my friends, it may make me drink more. So, it basically comes down to what type of friends one is comparing with and if they promote drinking or not’. (P394) – CMPR - ‘I believe it may be positive or potentially negatively influencing based on the actions of the other users’. (P754) – CMPR - ‘Comparing is not always that great. What if everyone is behaving in an unhealthy way?’. (P800) – CMPR - ‘I wouldn’t like to have something as personal as this tied to someone else’s performance, it could backfire if team members are not motivated’. (P698) – COOP - ‘It could also turn the other side. If you won’t get the rewards because someone else isn’t performing well, you might as well give up and join them in drinking anyway. Will you convince the other drinkers to stop, or will they convince you to join?’. (P861) – COOP	✓	✓	✓
5. It could annoy users and discourage them from using the persuasive health intervention: - ‘I do not like the competition aspect of this system, I think it could be very discouraging if you are constantly on the losing end’. (P519) – CMPT
‘… I like competition but I think in healthy living, it might turn to jealousy and cause people to stop altogether’. (P698) – CMPT - ‘It could be very discouraging if you are constantly on the losing end’. (P226) – CMPT	✓	X	X
6. It trivializes the importance of healthy behaviour: - ‘This is infantile’. (P16) – CMPT - ‘It’s very juvenile’. (P1013) – CMPT - ‘I don’t like competition in something as important as reducing alcohol intake. Too frivolous’. (P517) – CMPT	✓	X	X
7. It does not often take individual unique health conditions into account and may lead to falsification of health behaviours: - ‘I think adding competition to the app would lower the likelihood of people being truthful about their behaviour as the attention would be shifted to winning by all means even without altering behaviour’. (P999) – CMPT - ‘Living a healthy life is a personal goal. One’s personal use of alcohol cannot be in competition with another person’s. It is a competition against oneself. Competing to improve to be better than my previous self should be the strategy’. (P6) – CMPT - ‘It’s not about beating someone else. I have Type 1 Diabetes. My eating habits are completely different than someone else. I have to decide, with each meal, if it’s worth the pain of needles just to eat it. There’s no fair competition for that!’ (P692) – CMPT - ‘We are all unique and on our own journey. I would probably not use this app as a comparison’ (P356) – CMPR.	✓	✓	X
8. It encourages body shaming and health disorder (e.g. eating disorder): - ‘This kind of system institutes a belief that a person is better than another because of their lifestyle. I personally think it’s a terrible idea, and instead of people helping one another stay healthy it would turn into a competition that encourages shaming and poor attitudes about diet and personal value’. (P1001) – CMPT - ‘It might make someone have some weird eating disorder, whereby they try to beat their friends by eating less and not better’. (P508) – CMPT - ‘Could make the intentions of the program – having people eat healthier – be worse, by influencing anorexia and fighting between friends to see who could eat less’. (P864) – CMPT - ‘I can’t stand comparison like this where the users can feel smug or shameful when comparing their efforts to others, especially friends’. (P1702) – CMPR	✓	✓	X

‘✓’ indicates themes belonging to each strategy, ‘X’ shows themes that do not apply to a strategy. CMPT, CMPR, and COOP denote the strategy that a particular comment belongs to, the Competition, Comparison, and Cooperation, respectively.

Therefore, we recommend that to design PT interventions for people who react negatively to the direct and head-to-head interaction that is inherent in the competition and cooperation strategies but enjoy some indirect and subtle peer pressure, designers should employ the comparison strategy.

• Cooperation . The cooperation strategy has three unique strengths that differentiate it from the competition and the comparison strategies:

1. It offers opportunities to collaborate , make friends and interact with them.

2. It raises users’ sensitivity to disappointment and makes them work harder to avoid disappointing others.

3. It provides opportunities for mutual support and group encouragement .

The main distinguishing factor between cooperation and the other two socially-oriented strategies (competition and comparison) is that cooperation motivates people to change together and win together by offering opportunities for collaboration, mutual support, and group reinforcement. This distinguishes it from the competition and comparison strategies which tend to focus on individual achievement. For certain behaviours, such as the health behaviours, the healthier we are as a community, the better. It is not a mutually exclusive achievement. This is supported by the participants’ comments:

This is much more psychologically healthful–and helpful–than the other strategies. “Friends should celebrate their goals together and encourage each other, not be smug or feel superior.” (P100) – COOP.

“Friend support is far better than friend competition or comparison when seeking out lifestyle changes.” (P389) – COOP

Therefore, we recommend that designers who are interested in motivating people to change together should provide opportunities for people to collaborate and offer mutual support to each other using the cooperation strategy. Many health intervention initiatives are already geared towards promoting changing together by developing health interventions targeted at motivating groups of people such as families or an entire community to change together. For example, the ACT! Actively Changing Together ⁷⁰ by the YMCA Health and Well-Being Team is a nutrition, physical activity, and self-improvement intervention for helping teens and their families to change together.

Again, the unique strengths of the cooperation strategy also suggest that it may be more appropriate for designing PT health interventions targeted at people who are high in extraversion. Extraversion personality types are known for their love for making and interacting with friends.^13,71 The cooperation strategy provides a unique opportunity for them to achieve that. Therefore, to design PT interventions targeted at individuals who are high in extraversion, designers should employ the cooperation strategy which offers them the opportunity to satisfy their inherent needs of making and interacting with friends while motivating desirable behaviour change .

Similarly, the unique strength of raising users’ sensitivity to disappointment and making them work harder to avoid disappointing others suggests that cooperation may be more appropriate for people who are disappointment averse in line with the Theory of Disappointment Aversion. ⁷² Research has shown that overconfident and individualistic people are disappointment averse. ⁷³ Therefore, we recommend that to design for people from individualist cultural group or people with high individualist tendencies , ⁷⁴ designers could provide an opportunity for them to work together using the cooperation strategy . Although, this may seem contrary to the individualistic tendencies, they tend to be more inclined to an individual than group achievements. However, it makes sense considering the fact that individualists are driven by achievement ⁷⁴ and many have a low tolerance for failure. In cooperation, achievement is tied to group performance; therefore, an individualist could work harder to achieve success and avoid failure by not only performing the behaviour but also motivating others as long as the achievement is meaningful to him or her personally.

Summary of the strengths of the socially-oriented persuasive strategies

In summary, the socially-oriented strategies possess 10 major strengths that shed light on the mechanisms through which they motivate behaviour change in general. Individually speaking, the competition strategy has four major strengths. They include its tendency to make

1. people committed to and focused on the behaviour;

2. give a sense of accomplishment ;

3. engage and challenge people;

4. make behaviours fun, exciting, interesting , and appear easier to do than usual.

Similarly, the comparison strategy possesses six major strengths that provide insight into the mechanism through which it can motivate health behaviour change. They include its tendency to make

1. people committed to and focused on the behaviour;

2. allow for subtle and e mpowering peer pressure;

3. engage and challenge people;

4. make behaviours fun, exciting, interesting , and appear easier to do than usual;

5. offer opportunity to serve as a positive role model ;

6. provide opportunities for people to stay responsible and accountable to others.

Finally, the cooperation strategy possesses six major strengths, which include its tendency to

1. make behaviours fun, exciting, interesting , and appear easier to do than usual;

2. offer an opportunity for users to serve as positive role models ;

3. provide opportunities for mutual support, group encouragement, and reinforcement;

4. provide opportunities for people to stay responsible and accountable to others;

5. raise users’ sensitivity to disappointment and make them work harder to avoid disappointing others;

6. offer opportunities to collaborate , make , and interact with friends.

With respect to the relation between the three socially-oriented strategies, the competition and the cooperation strategies are the most distinct of all. They share only one strength of making behaviours fun, exciting, interesting , and appear easier to perform than usual in common. This suggests that competition and cooperation may work well together as complementary strategies in PT health interventions. There are many ways that PT health interventions can apply a hybrid strategy we call cooperative–competition strategy. For example, a PT health intervention can employ the cooperation strategy to allow for intra-group collaboration and at the same time the competition strategy to allow for inter-group competition. The cooperative–competition strategy would harness the strengths of both the cooperation and competition strategies to motivate the desired health behaviour change while overcoming some of their weaknesses. For example, the ACT! Actively Changing Together ⁷⁰ by the YMCA Health and Well-Being Team described above could implement the cooperative–competition strategy to motivate not only a family but also an entire community. Each family member could collaborate and help each other to perform the desired behaviour (cooperation) to outperform the other families within the community that are involved in the intervention (competition). This approach allows the individual family to participate in both the competition and the cooperation.

On the other hand, competition and comparison and cooperation and comparison strategies seem equally related. Each of the pairs shares two strengths in common.

Finally, if a PT health intervention aims to promote the adoption of healthy behaviour by making the behaviour fun and exciting to do, any of the socially-oriented strategies (competition, comparison, and cooperation) could do the job. They all have the potential to make healthy behaviour performance fun and exciting.

The common weaknesses of the socially-oriented strategies

Our findings reveal that the socially-oriented strategies share some common weaknesses as well as some unique weaknesses (that are specific to the individual strategies). The weaknesses shed light on the mechanism through which the strategies could hinder the effectiveness of any PT health intervention at motivating the desired behaviour change.

The three socially-oriented strategies share two main weaknesses in common:

1. They could be invasive and jeopardize an individual’s privacy and relationships .

2. They could backfire and encourage unhealthy behaviour.

This means that PT health intervention designers should plan adequate mechanisms to deal with these weaknesses and we propose some mechanisms in Table 4.

Table 4.

Summary of the design guidelines for socially-driven persuasive health intervention design, not in any particular order.

Guideline 1: Design to preserve users’ privacy. Preserve user’s privacy when using any socially-oriented persuasive strategies in health intervention design. Our findings show that three socially-oriented strategies competition, social comparison, and cooperation have a high likelihood of being intrusive, less privacy-preserving, and a high tendency of hurting relationships. This may make people reluctant to adopt and use any socially-driven health intervention employing them or their efficacy in general. Some participants highlighted that they would not use any persuasive health intervention that involves disclosing their personal data. ‘This works for me only if you make all participants anonymous’ (P301). ‘I would not use this app because it is not private. If it does not indicate how many calories your friend ate, but just tells you that you did better or worse than your friend, I think I would like this app better’ (P171). Therefore, we recommend that to overcome the privacy issues often inherent in the socially-oriented strategies, persuasive health intervention designers should implement mechanisms that let users conceal their identity or use nicknames. Designers could also make it possible for users to work with strangers who do not know them. Although it is possible that anonymizing persuasive health intervention users’ identity may reduce the persuasive influence of the intervention and their efficacy in general, we think that it is a good compromise for achieving privacy-preserving persuasive interventions that users would be happy to adopt and use. Alternatively, persuasive health intervention designers should abstract user’s behaviour performance data as a way of preserving privacy. For example, displaying behaviour performance data as a percentage of an individual’s behaviour goal may be a good abstraction and less privacy invasion option to showing an actual behaviour performance data as shown by the sample participant’s comment: ‘Learning specific information about another user’s calorie intake would be a huge invasion of privacy to me. If it were a simple percentage reported, then I would enjoy using the system’. (P1590)

Guideline 2: Avoid counterproductive design. Ensure that employing socially-oriented strategies in persuasive health intervention will not be counterproductive (backfire); there is the possibility of positive and negative social influence. Our study shows that employing the three socially-oriented strategies (competition, social comparison, and cooperation) in persuasive health intervention designs could be counterproductive by demotivating healthy behaviours or encouraging unhealthy behaviours if not carefully implemented. As highlighted by the comments, ‘This type of game could go both ways … if I drink less than my friends, it may make me drink more. So, it basically comes down to what type of friends one is comparing with and if they promote drinking or not’ (P394). ‘… Points could end up being rewarded for risky behaviour, just because they were better than their friends. That’s wrong. It could backfire’ (P1590). ‘Comparing is not always that great. What if everyone is behaving in an unhealthy way?’ (P800). Therefore, designers should take extra care when employing socially-oriented strategies in persuasive health intervention designs to reduce the likelihood of downwards comparison and negative social influence. Designers can pre-screen and redistribute users across groups to ensure effective social circle for comparison and social influence. Designers can also include mechanisms that allow for both within-group and between-group comparisons to reduce the possibility of downwards comparison.

Guideline 3: Design to reduce cheating. Implement mechanisms to deter cheating and build trust among the persuasive health intervention users . A lack of trust among persuasive health interventions users that none of the users in their social group is cheating is a common weakness of the competition and comparison strategies. As highlighted by the comment, ‘This will work only if I really trust that the people I’m playing with will not cheat’ (P957). ‘Competition is the best motivation, there would need to be system so that people couldn’t cheat’ (P980). ‘This works only if there’s no cheating’ (P907). Therefore, for competition and comparison-oriented persuasive health interventions to be really effective, designers should implement mechanisms that deter users from cheating and hence win participants’ trust in the persuasive health intervention.

One way to reduce cheating is to automatically monitor users’ behaviours using various sensors (that are capable of monitoring health behaviours in real time) and avoid self-reporting of behaviours. For example, various activity tracking sensors exist that can be used to automatically track an individual’s daily physical activity. However, there are many health behaviours that cannot be automatically monitored to date; for such behaviours, we recommend that persuasive health intervention designers should emphasize the intrinsic benefit of behaviours to an individual’s self. That may help reduce the urge to cheat to outperform others and effectively promote healthy behaviours.

Guideline 4: Design to allow for self-competition and self-comparison in persuasive health interventions. Allow for self-competition and self-comparison in persuasive health intervention design. Their inherent tendency to cause tension and jeopardize privacy and friendship is a major drawback of the competition and comparison strategies (as discussed above). Most of our participants fear that competition and comparison may be inappropriate for motivating healthy behaviour. They highlighted the need for competition and comparison to be with and against oneself. As shown by the comment, ‘Living a healthy life is a personal goal. One’s personal use of alcohol cannot be in competition with another person’s. It is a competition against oneself. Competing to improve to be better than my previous self should be the strategy’ (P6). ‘… As a comparison method, I would prefer to compare my average overall daily performance, not my friends – keep it private’ (P471). This is in line with previous research that found that users complained about using competition to motivate healthy behaviour17,54,77 and may even become discouraged if they lose. 27 Therefore, to overcome these shortcomings, we recommend that designers should provide a mechanism for persuasive health intervention users to compare their health behaviour performance data and compete to break their own record and reward them accordingly. This could complement conventional competition strategy and can also replace it for users who react negatively or are not receptive to competing with other people to improve their behaviours.

Guideline 5: Allow multiple winners and winning conditions in persuasive health intervention design. Reduce the likelihood of unhealthy competition and body shaming by allowing for multiple winners and winning categories in persuasive health intervention. A major strength of the cooperation strategy as highlighted by our participants is that it provides an opportunity for people to collaborate, change together, and win together as shown by the comment, ‘This is the best of the systems in my opinion because the more people with the same goal, the more power there is available for achieving that goal in many ways, including support and morale boosting for one another’ (P651). On the other hand, one of the drawbacks of the competition and comparison strategies is that winning often entails the other users losing – mutually exclusive achievement. This mutually exclusive achievement tendency inherent in the competition and the comparison strategies is well captured by Kohn’s 78 statement, ‘to say that an activity is structurally competitive is to say that it is characterized by what I will call mutually exclusive goal attainment. This means, very simply, that my success requires your failure’. However, for many behaviours, especially healthy behaviours, the healthier we are as a community, the better for everyone. Therefore, to overcome this weakness, we recommend that persuasive health intervention designers should design to avoid (or at least reduce the tendency of) unhealthy competition and encourage changing together by allowing for multiple winners at a time and winning conditions in their systems. This is supported by participants’ comment such as ‘It is very motivational; it should be possible for more than one person to win by staying healthy’ (P759). Again, to reduce the tendency of provoking body shaming and health disorder using socially-driven persuasive health intervention, we recommend that designers implement multiple health behaviour performance measures that are not necessarily focused on only easily observable health index (such as weight) but on holistic health and wellness.

Guideline 6: Ensure fair comparison and competition in design. Ensure fair comparison and competition in persuasive health intervention design. Our participants highlighted the need to ensure fair competition and comparison when using socially-driven persuasive health interventions by avoiding matching and comparing dissimilar people and by comparing only realistic and representative behaviour measures. A particular participant who was 65 years old narrated how it would be unfair to compare her physical activity level with that of a youth in his 20s. This, she said, would obviously discourage her since it is an unfair comparison. Similarly, another participant pointed out that blood alcohol content (BAC) may not be a reliable behaviour measure for comparison since it depends on many individual characteristics that may vary from one user to another as can be seen in the sample participant’s comment, ‘Amount of alcohol doesn’t affect BAC in the same way for everyone. Some people would have an inherent advantage in this game, and that would remove the little motivation I’d feel for winning “points”’ (P928). Therefore, we recommend that designers should ensure fair competition and comparison by not comparing dissimilar people and by measuring and comparing only realistic behaviour measures.

Guideline 7: Supplement competition and comparison with other compatible strategies in design. Supplement competition and comparison in design with strategies to build and maintain self-efficacy . The competition and comparison strategies have the tendency to make people lose their self-esteem and self-confidence especially when they are constantly being outperformed. Therefore, we recommend that PT health interventions employing the competition or the comparison strategy should employ alongside, strategies to build self-efficacy in its users and reaffirm their individual abilities (irrespective of the outcome of the competition and the comparison).

Guideline 8: Employ the competition, comparison, or cooperation in designs to make behaviours fun and exciting. Make behaviour fun and exciting using the competition, comparison, or cooperation . Many people are demotivated from adopting healthy behaviour because they perceive it as boring. The three socially-oriented strategies share a common strength of making behaviours fun, exciting, interesting, and appear easier to do than usual. Therefore, we recommend that to make healthy behaviours fun and exciting, designer should employ the competition, comparison, or the cooperation strategy in designs.

Guideline 9. Employ competition or comparison strategy to make people committed. Make people focused and committed to the behaviour using the competition or the comparison. The competition and comparison strategies share common strengths of making people committed, engaged, focused, and challenged enough to push towards their health behaviour goals. Therefore, we recommend that PT interventions targeted at audience who are hindered from adopting healthy behaviour by their lack of commitment, focus, and adequate challenge should employ the competition or comparison to motivate and promote desired health behaviour change.

Guideline 10: Employ cooperation or comparison to design for people who care about their public image. Employ cooperation or comparison to design for people who are interested in maintaining a positive public image . The cooperation and comparison strategies share common strengths of providing opportunities for individuals to serve as role models, be accountable to others, and stay responsible. Therefore, we recommend that to design for people who are concerned about maintaining a positive public image and serving as positive role models to others by staying responsible and accountable, designers should employ either the cooperation or the comparison strategy.

Guideline 11: Employ competition to give a sense of accomplishment. Employ the competition strategy to give users a sense of accomplishment and motivate behaviour change . Adopting healthy behaviour lacks the immediate feeling of what we call health behaviour performance accomplishment which could be a major motivator for many people. The one unique strength that differentiates the competition strategy from the comparison and cooperation strategies is its tendency to gives users an immediate sense of accomplishment. Therefore, we recommend that PT health interventions targeted at audience who are discouraged from adopting healthy behaviour by the lack of immediate sense of accomplishment associated with many healthy behaviours should employ the competition strategy to give the users an immediate sense of accomplishment and motivate behaviour change.

Guideline 12: Employ comparison to provide some subtle and empowering peer pressure. Employ the comparison strategy to provide some indirect and subtle peer pressure and motivate behaviour change. The comparison strategy has a unique strength of allowing for subtle and empowering peer pressure that differentiates it from the competition and cooperation strategies. Therefore, we recommend that to design PT interventions for people who react negatively to the direct and head-to-head interaction that is inherent in the competition and cooperation strategies but enjoy some indirect and subtle peer pressure, designers should employ the comparison strategy.

Guideline 13: Employ cooperation to motivate people to ‘change together’. Employ the cooperation strategy to motivate people collaborate and ‘change together ’. The cooperation strategy has unique strengths of offering opportunities for people to collaborate, interact, and make friends while offering mutual support and group encouragements. Therefore, we recommend that designers who are interested in motivating people to change together should provide opportunities for people to collaborate and offer mutual support to each other using the cooperation strategy.

Guideline 14: Employ cooperation to motivate extraversion. Employ the cooperation strategy to motivate people who are high in extraversion personality trait. As discussed above, the cooperation strategy has unique strengths of offering opportunities for people to collaborate, interact, and make friends while offering mutual support and group encouragements. Extraversion personality types are known for their love for making and interacting with friends.13,71. The cooperation strategy provides a unique opportunity for them to achieve that. Therefore, to design PT interventions targeted at individuals who are high in extraversion, designers should employ the cooperation strategy which offers them the opportunity to satisfy their inherent needs of making and interacting with friends while motivating desirable behaviour change.

Guideline 15: Employ cooperation to motivate individualist-oriented people. Employ the cooperation strategy to motivate individualistic people. The cooperation strategy has a unique strength of raising users’ sensitivity to disappointment and making them work harder to avoid disappointing others. Research has shown that individualistic people are disappointment averse. 73 Therefore, we recommend that to design for people from individualist cultural group or people with high individualist tendencies, 74 designers could provide an opportunity for them to work together using the cooperation strategy. Although this may seem contrary to the individualist tendencies, they tend to be more inclined to individual than group achievements.79,80 However, it makes sense considering the fact that individualists are driven by achievement 74 and many have a low tolerance for failure. In cooperation, achievement is tied to group performance; therefore, an individualist could work harder to achieve success and avoid failure by not only performing the behaviour but also motivating others as long as the achievement is meaningful to him or her personally.

In addition to the weaknesses shared by the three strategies, the competition and comparison share three weaknesses in common:

1. They could reduce self-esteem , cause depression , make people lose confidence in themselves and their ability and feel alienated .

2. They do not often take individual unique conditions into account and may lead to falsification of behaviour.

3. They encourage body shaming and health disorder (e.g. eating disorder).

The findings suggest that designers employing the competition or the comparison strategies in PT health intervention design should devise approaches to overcome the loss of self-confidence and self-esteem often associated with these strategies. Therefore, we recommend that a PT health intervention employing the competition or the comparison strategy should employ, alongside, strategies to build self-efficacy in its users and reaffirm their individual abilities (irrespective of the outcome of the competition and the comparison strategies) . Self-efficacy according to the Health Belief Model ⁷⁵ is an individual’s belief in his or her ability to perform the desired behaviour. There are several established strategies for building self-efficacy including performance accomplishment. ⁶⁹ Offering individuals/personal rewards that are not tied to others people’s behaviours (such as giving achievement badges and points ²⁰ ) can give a sense of performance accomplishment ⁷⁶ and reaffirm an individual’s abilities.

To avoid creating opportunities for body shaming when employing the competition and comparison strategies, we recommend that PT health intervention designers should implement multiple performance measures that are not focused on only easily observable health index . For example, a healthy eating intervention, as opposed to focusing on the amount of calorie consumed or pounds lost, could also focus on how many servings of fruits and vegetables an individual consumed and their overall daily physical activity.

Similarly, the competition and cooperation strategies share only one additional weakness in common:

• They could cause unnecessary stress, tension, pressure and make people anxious .

This finding suggests that the direct involvement and engagement with other people, inherent in the operationalization of the competition and cooperation strategies, is probably what causes anxiety and stress since that is the major difference between the competition and cooperation strategies and the comparison strategy. Comparison strategy tends to involve indirect peer pressure. This is supported by the following participants’ comments about the cooperation strategy:

“If I did go in with a friend, I would feel more pressure to perform to not let them down. It creates unnecessary tension. Better to pace myself.” (P57)

“It can create tension between people and create opportunities for negative criticism.” (P56)

Therefore, we recommend that to reduce the tendency of stressing people who respond negatively to the direct peer pressure the competition and cooperation strategies may generate, PT health intervention designers should provide options that allow individuals to disable any competition and cooperation features and work alone and reward them based on their individual achievements. PT health intervention designers could implement the competition and cooperation strategies as a customizable feature.

On the other hand, the cooperation and comparison strategies are very distinct with respect to their weaknesses. They share no additional weaknesses in common apart from that shared by the three socially-oriented strategies.

The unique weaknesses of the socially-oriented strategies

There are some weaknesses that are specific to some of the strategies that designers need to take into consideration when employing the strategies:

• Competition . The competition strategy has two unique weaknesses that differentiate it from the comparison and cooperation strategies:

• It could annoy users and discourage them from using the PT health intervention.

• It trivializes the importance of healthy behaviour.

Some of our participants reported that the competition strategy could trivialize the importance of health behaviour and discourage them. This is captured in the following sample comments:

“I do not like the competition aspect of this system, I think it could be very discouraging if you are constantly on the losing end.” (P519)

“Living a healthy life is a personal goal. One’s personal use of alcohol cannot be in competition with another person’s. It is a competition against oneself. Competing to improve to be better than my previous self should be the strategy.” (P6)

“I don’t like competition in something as important as reducing alcohol intake. Too frivolous.” (P517)

The first comment suggests that people get discouraged when they are constantly losing in a competition not necessarily because of their inability to perform the desired behaviour but their inability to outperform the other party and win the competition. This is mostly because competition allows only one winner at a time in most cases irrespective of each individual’s performance. Therefore, we recommend that PT health intervention designers employing the competition strategy should accommodate multiple winners and multiple performance measures . Again, care should be taken when employing the competition strategy and rewarding winners to avoid creating the impression that the benefit of adopting healthy behaviours can be reduced to the reward, fun, and joy of winning, thereby trivializing the actual benefit .

• Comparison and Cooperation . Finally, social comparison and the cooperation strategy have no unique weaknesses apart from that shared with the other strategies.

Summary of the weaknesses of the socially-oriented persuasive strategies

In summary, the socially-oriented strategies possess eight major weaknesses that shed light on the reasons they may not work as expected in some PT health interventions in general. Individually, the competition strategy is associated with all of the eight weaknesses listed in Table 3.

On the other hand, the comparison strategy possesses five major weaknesses, which include its tendency to

1. reduce self-esteem, cause depression, makes people lose confidence in themselves and their ability and feel alienated;

2. be invasive and jeopardize an individual’s privacy and relationships;

3. backfire and encourage unhealthy behaviour;

4. encourages body shaming and health disorder (e.g. eating disorder);

5. not often take individual unique conditions into account and may lead to falsification of behaviour.

Finally, the cooperation strategy possesses only three major weaknesses including its tendency to

1. be invasive and jeopardize an individual’s privacy and relationships;

2. backfire and encourage unhealthy behaviour;

3. cause unnecessary stress, tension, pressure and make people anxious.

Summary of design guidelines

Although each of the socially-oriented strategies harnesses the principle and the power of social influence to motivate behaviour, they differ in their operationalization of the principle. As a result, there are some common strengths and weaknesses that are shared by the strategies and, at the same time, some unique strengths and weaknesses that are specific to each of the strategies. Designers need to take these strengths and weaknesses into consideration when employing the strategies as they would impact the success of the socially-driven persuasive health interventions. Therefore, we have developed some design guidelines based on our findings to guide the design of socially-driven persuasive health interventions employing the competition, social comparison, and the cooperation strategies. Since most of the design recommendations are already discussed in the ‘Discussion’ section, Table 4 presents only a summary of some guidelines. The guidelines are by no means comprehensive or exhaustive; many other guidelines can be generated from the mapping of the strengths and weaknesses of the strategies presented in Tables 2 and 3, respectively.

Limitations

First, we report the perceived persuasiveness of the socially-oriented strategies implemented in storyboards; the actual persuasiveness may differ when implemented in a specific socially-driven persuasive health intervention and evaluated in real-world. Therefore, in future work, we plan to examine the persuasiveness of the strategies along with their strengths and weaknesses in an actual PT health intervention. Second, our work has benefitted from the large-scale exploratory studies of the strategies with respect to unhealthy alcohol behaviour change and healthy eating behaviour and we can claim applicability in other health behaviour domains (because of the high-level nature of the storyboard depicting the strategies); however, our results may not generalize to other behaviour domains. Therefore, the results should be applied with caution to other health behaviour domains. Finally, it is possible that the study population distribution may differ across the two studies.

Summary and conclusion

Socially-driven persuasive health interventions have recorded some mixed findings regarding their effectiveness at motivating health behaviours. The socially-oriented persuasive strategies (competition, social comparison, and cooperation) are the major components of socially-driven persuasive health interventions and have been widely employed. In this study, we investigated the mechanism through which the three socially-oriented strategies could influence health behaviours either positively or negatively by exploring their strengths and weaknesses via a large-scale study of 1898 participants. The findings show that because each of the strategies harnesses the principle and the power of social influence to motivate behaviour change, they share some common strengths (such as their tendency to make health behaviours fun, exciting, interesting , and appear easier to do than usual) and weaknesses (such as their tendency to be invasive and jeopardize an individual’s privacy and relationships ).

However, because of the differences in the operationalization of the social influence principle across the three strategies, some strengths and weaknesses are unique to the individual strategies or subsets of the strategies. Some of the strengths are as follows: competition makes one committed and gives a sense of accomplishment ; comparison allows for subtle and empowering peer pressure and provides an opportunity for individuals to serve as role models , and cooperation provides opportunities for mutual support and encouragement . On the other hand, some of their weaknesses are as follows: competition could trivialize the importance of healthy behaviour; comparison could encourage body shaming and health disorder (e.g. eating disorder); and cooperation could cause unnecessary stress, tension, pressure and make people anxious .

As a secondary objective, we validated the persuasiveness of the strategies and showed their comparative persuasiveness with respect to their ability to motivate the desired healthy behaviour change. Our findings show that, in general, the socially-oriented strategies are perceived as persuasive with the social comparison strategy being the most persuasive of all.

Based on the findings, we developed 15 design guidelines for implementing the socially-oriented persuasive strategies in health interventions to overcome their weaknesses and amplify their strengths.