The use of smartphones has become an integral part of everyone's lives. Due to the ubiquitous nature and multiple functionalities of smartphones, the data handled by these devices are sensitive in nature. Despite the measures companies take to protect users’ data, research has shown that people do not take the necessary actions to stay safe from security and privacy threats. Persuasive games have been implemented across various domains to motivate people towards a positive behaviour change. Even though persuasive games could be effective, research has shown that the one-size-fits-all approach to designing persuasive games might not be as effective as the tailored versions of the game. This paper presents the design and evaluation of a persuasive game to improve user awareness about smartphone security and privacy tailored to the user's motivational orientation using Regulatory Focus Theory. From the results of our mixed-methods in-the-wild study of 102 people followed by a one-on-one interview of 25 people, it is evident that the tailored version of the persuasive game performed better than the non-tailored version of the game towards improving users’ secure smartphone behaviour. We contribute to the broader HCI community by offering design suggestions and the benefits of tailoring persuasive games.

Increased physical activity has been shown to reduce morbidity and mortality among adults. Over the years, mobile apps have been developed to encourage people to engage in physical activity, such as walking or running, by employing various persuasive strategies. However, the choice of these strategies is often based on designers' intuition without knowing if the strategies will be effective for target audience and the target behaviour. To address this gap, we conduct a study with 103 adults to assess the perceived effectiveness of 12 widely used strategies in health games design. The strategies are based on the Persuasive Systems Design (PSD) framework. Our results reveal that the strategies are effective for promoting physical activity at varying degrees. These results inform the development of the game, called TreeCare. Next, we conduct a 3-week field study involving 23 target users to evaluate the game in terms of effectiveness and usability. Our results show that TreeCare significantly improved users' physical activity levels. In addition, the game is found to be easy to use, engaging, aesthetically pleasing, and enjoyable. We reflect on our findings and offer practical guidelines to inform the design of effective and usable persuasive applications.