Gian-Luca Savino

Research in HCI has shown a growing interest in unethical design practices across numerous domains, often referred to as "dark patterns". There is, however, a gap in related literature regarding social networking services (SNSs). In this context, studies emphasise a lack of users' self-determination regarding control over personal data and time spent on SNSs. We collected over 16 hours of screen recordings from Facebook's, Instagram's, TikTok's, and Twitter's mobile applications to understand how dark patterns manifest in these SNSs. For this task, we turned towards HCI experts to mitigate possible difculties of non-expert participants in recognising dark patterns, as prior studies have noticed. Supported by the recordings, two authors of this paper conducted a thematic analysis based on previously described taxonomies, manually classifying the recorded material while delivering two key fndings: We observed which instances occur in SNSs and identifed two strategies-engaging and governing-with fve dark patterns undiscovered before. CCS CONCEPTS • Human-centered computing → Empirical studies in HCI; HCI theory, concepts and models; Empirical studies in interaction design; Interaction design theory, concepts and paradigms; • Security and privacy → Usability in security and privacy.

Cycling is on the rise as a relevant alternative to car-based mobility and even though there are mobile applications specifically designed for cyclists to support this development, many still face unresolved challenges in terms of safe user interaction with complex data while riding. We present the design, development, and evaluation of VeloCity - an application for reporting traffic incidents and structures relevant to cyclists. In a case study, we compared its’ three input methods (touch, in-app speech recognition, the voice assistant of the operating system) to evaluate which attributes make for safe interaction while cycling. We found that participants prefer to use the voice assistant over the other modalities as it was the least distracting due to its hands- and eyes-free interaction design. Furthermore, they chose short commands over conversational phrases. Based on our results, we present five guidelines for designing voice user interfaces for cyclists and argue for moving away from touch-based interfaces in this domain, which still make up most of the applied interaction techniques today.

In the last two decades, digital mobile navigation technologies have been replacing physical tools (i.e. physical maps), revolutionizing how people navigate familiar and unfamiliar spaces. Initially designed for in-car use, mobile navigation systems are being continuously adapted for other modes of transportation and novel user groups. However, the underlying system architecture is not being adapted to its new users. We have seen rapid technological evolution in each of the individual modules of the system architecture of turn-by-turn (TBT) based mobile navigation systems. Still, the overall architecture has remained the same. From a Human-Computer Interaction (HCI) perspective, this rigidity is rather unusual. However, in recent years we have seen the design space for mobile navigation technologies decouple from the prototypical architecture of TBT-based mobile navigation systems. People are combining existing and new modules to design and develop completely different and novel mobile navigation systems. This thesis systematically explores this decoupling. To assess the mobile navigation systems that result from this decoupling, Chapter 2 of this thesis presents a novel method which gives us a better understanding of usage patterns and peoples intentions when they are using mobile navigation applications. Chapter 3 shows that cyclists benefit from orientation-based navigation systems. In Chapter 4 we show that the environment (i.e. the street network) influences how successfully certain mobile navigation systems can be used. Chapter 5 explores how we can improve the user experience of orientation-based navigation methods by simulating human navigation behavior. Finally, Chapter 6 presents a study on avoiding the risks of decoupling the design space for mobile navigation technologies by the designing and introduction voice assistant-based input modalities for cyclists. In summary, mobile navigation technologies are undergoing a transformation. Decoupling the design space from its former system architecture results in novel mobile navigation systems and use-cases. Presenting a systematic approach for assessing these novel mobile navigation systems and still ensuring that interactions are safely designed, this thesis, based on an HCI perspective, contributes to the understanding, evaluation, and improvement of mobile navigation systems for specific user groups.