Psychological targeting tries to influence and manipulate users' behaviour. We investigated whether users can protect themselves from being profiled by a chatbot, which automatically assesses users' personality. Participants interacted twice with the chatbot: (1) They chatted for 45 minutes in customer service scenarios and received their actual profile (baseline). (2) They then were asked to repeat the interaction and to disguise their personality by strategically tricking the chatbot into calculating a falsified profile. In interviews, participants mentioned 41 different strategies but could only apply a subset of them in the interaction. They were able to manipulate all Big Five personality dimensions by nearly 10%. Participants regarded personality as very sensitive data. As they found tricking the AI too exhaustive for everyday use, we reflect on opportunities for privacy protective designs in the context of personality-aware systems.

Mindfulness is a term seen with increasing frequency in HCI literature, and yet the term itself is used almost as variously as the number of papers in which it appears. This diversity makes comparing or evaluating HCI approaches around mindfulness or understanding the design space itself a challenging task. We conducted a structured ACM literature search based on the term mindfulness. Our selection process yielded 38 relevant papers, which we analyzed for their definition, motivation, practice, evaluation and technology use around mindfulness. We identify similarities, divergences and areas of interest for each aspect, resulting in a framework composed of four perspectives and seven lines of research. We highlight challenges and opportunities for future HCI research and design.

In this paper we investigate whether a helmet-mounted display for motorcyclists can provide similar benefits as the established head-up display (HUD) in cars. HUDs can increase driving safety by efficiently informing the driver. Given their high safety risks, such a technology seems overdue for motorcyclists. Only recently, several crowdfunding projects have raised substantial funding for helmet-mounted displays, however, none of them has released a commercial product yet. In order to investigate display concepts, we developed an easy-to-reproduce and low-cost helmet-mounted display prototype and compared it to a conventional display setup. The helmet-mounted display was rated more attractive and induced a lower workload. Those motorcyclists who generally exceeded the speed limit before also rode significantly slower when using the head-mounted display. We argue that an intelligent HUD application that adapts to the rider»s behavior and preferences could further enhance safety and improve user experience for motorcyclists. We encourage other researchers to replicate our setup and to investigate the impact of HUDs on motorcyclists' behavior and road safety.

The ever-increasing amount of information in cars demands novel and safer displays, such as head-up or windshield displays. We present two studies that investigate the recognition of stimuli presented on a windshield display. Using a divided attention task and a driving simulator, we first compared four types of stimuli which are common in traffic signs: text, circles, triangles, and squares. We measured the response times at 17 positions within an extended field of regard of 35°x15°. The follow-up study validated our results by replicating the first study with two changes: We investigated the influence of peripheral workload with a more diverse simulated environment and tested for training effects by converting the setup to a left-hand drive car. We contribute response times and sizing recommendations for a field of regard of 35°x15°. These recommendations will help designers of large head-up displays to create interfaces which are well-legible and avoid both cluttering the driver's view and occluding the road scene.

Autonomous cars will likely hit the market soon, but trust into such a technology is one of the big discussion points in the public debate. Drivers who have always been in complete control of their car are expected to willingly hand over control and blindly trust a technology that could kill them. We argue that trust in autonomous driving can be increased by means of a driver interface that visualizes the car's interpretation of the current situation and its corresponding actions. To verify this, we compared different visualizations in a user study, overlaid to a driving scene: (1) a chauffeur avatar, (2) a world in miniature, and (3) a display of the car's indicators as the baseline. The world in miniature visualization increased trust the most. The human-like chauffeur avatar can also increase trust, however, we did not find a significant difference between the chauffeur and the baseline.

Windshield displays (WSDs) are the big siblings of Head-up displays (HUDs). They are assumed to cover the entire windshield and to allow displaying content at continuous depth, eventually. This creates a large and unstructured 3D space for information display -- raising the question what to display where. To address this question, we developed a view management concept for WSDs in left hand drive cars which proposes zones and areas for specific information. As driving is a safety-critical task, we designed the initial concept with the driver's perceptual abilities in mind. Subsequently, we gathered insights into the driver's needs and desires from a formative study. We asked participants where they would place different types of information after inspiring their imagination by a 3D driving scene and WSD information on a Google Cardboard. The improved concept respects both the drivers' needs and desires and their perceptual abilities and can serve as a basis for view management concepts of future WSD.

In this paper we present a design space for interactive windshield displays in vehicles and discuss how this design space can support designers in creating windshield applications for drivers, passengers, and pedestrians. Our work is motivated by numerous examples in other HCI-related areas where seminal design space papers served as a valuable basis to evolve the respective field -- most notably mobile devices, automotive user interfaces, and interactive public displays. The presented design space is based on a comprehensive literature review. Furthermore we present a classification of 211 windshield applications, derived from a survey of research projects and commercial products as well as from focus groups. We showcase the utility of our work for designers of windshield applications through two scenarios. Overall, our design space can help building applications for diverse use cases. This includes apps inside and outside the car as well as applications for specific areas (fire fighters, police, ambulance).

Drivers attend to a lot of information at various locations inside and outside the car as well as on external devices (e.g. smart phones). Head-Up Displays (HUDs) support keeping drivers' visual focus directed towards the street; as they present virtual information in the windshield area on top of the physical world within the field of view of the driver. Displayed information, however, is often spatially dissociated with its cause in the physical world: for example a warning is displayed, yet drivers still require time searching for the hazard causing it. Windshield displays (WSDs) allow virtual warnings being displayed at the position of the hazard. We compared HUD and WSD with the baseline no-display and found that drivers demonstrate a calm gaze behavior with WSDs; they keep their visual attention in average 1.5 s longer focused on the leading car. However, we also found no significant faster reaction time compared to HUDs. We discuss our findings comparing HUDs to WSDs, present potential limitations of our study and point out future steps in order to further investigate the advantages of WSDs.

Windshield displays (WSDs) are information displays covering the entire windshield. Current WSD test setups place information at different distances, but always within the driver's foveal field of view. We built two WSD test setups, which present information not only at various distances within the driver's visual focus, but also in the peripheral field of view. Then we evaluated the display of information in the periphery on both WSD setups in a user study. While making sure the participants would look at the peripheral information, we measured the display's impact on driving performance. Subjects were also asked about their driving experience with the windshield displays and their preference among the two setups.

Currently, the processes used by many car manufacturers to adapt information from the head unit to the intended display platform are outdated and extremely cumbersome. The individual graphic elements are not designed for use in different contexts and many steps must be done manually to achieve a proper in-vehicle information visualization. Additionally, the amount of data that must be maintained is extremely large, resulting in strong restrictions in the variability of appearance and displayed information. An additional challenge is that multiple car brands belong to the same main company with each brand having a separate identity. Therefore, the graphical user interface (GUI) elements require resizing and recomposition which then reflects the brand's heterogeneous characteristics. To overcome these drawbacks we present a software solution to create and edit flexible, in-vehicle GUIs through reusable elements or widgets that adjust their size and composition to their environmental context in a dynamic and automatic manner. We have examined the quality of the tool through validation rules for each step and proposed calculation algorithms as a possible approach for a largely automated evaluation.