How people come to trust computing technology is an important factor in the degree to which they come to accept the services that such technologies are able to provide. This is particularly important where the usage of a technology might risk compromising a person’s private information, making them vulnerable to technologically mediated attack. Research into interpersonal trust development between people has allowed designers of systems deployed using technologies such as the World Wide Web to successfully modulate a number of human interpersonal trust cues into the computer-mediated communication domain. Pervasive computing however, describes a significant shift in the ways in which people will come to encounter and use interactive technologies. No longer limited to the confines of the desktop, people can and will be able to perform many of the technological activities they would otherwise do at home in any place and at any time. However, while the services that a pervasive computing infrastructure will be able to provide may be similar to those that people are used to in the traditional world of the ‘desktop metaphor’, the novel characteristics of pervasive computing mean that many of the trust cues that were previously available to technology users may no longer offer an effective means of helping users to place their trust well. In this thesis, a mixed methods research plan, involving both laboratory-based and field-based experimental design, was developed to investigate the role of human-computer trust in respect of two novel characteristics of pervasive computing: service discovery and secure ad-hoc device association. Through leveraging various artefacts in the immediate physical world to support information presented by services in the digital world, this thesis posits that the provision of user-verifiable links between the physical and digital worlds might provide a means of increasing user trust in services whose source they can otherwise not perceive nor verify.

This thesis investigates the impact of the voice modality on user trust in conversational chatbot interfaces. The assumption is that trust can be increased by adding voice output to a chatbot and by a higher quality of a used text-to-speech synthesis. The thesis first introduces chatbots and the concept of conversational interfaces then defines trust in an online context. Based on this, a model for trust and perceiving factors for credibility, ease of use and risk is defined. An online experiment is conducted where participants run through conversational scenarios with a chatbot while varying the voice output. Followed by a survey to collect data about the perception of the trust factors for a scenario with no voice and two scenarios with different speech synthesis qualities. To analyse the ordinal data from the survey the ”Wilcoxon signed- rank test”, a nonparametric statistical test, is conducted to compare trust for the voice output types. Results show that adding the voice output modality to a conversational chatbot interface increases the user trust towards the service. Furthermore, the assumption that synthesis quality has an effect on trust could not hold true because the results are not statistically significant. On this basis, the limitations of the used methods are discussed and suggestions for further research are proposed. / Detta examensarbete undersöker den inverkan som röstmodaliteten har på användarförtroende i konversationsbaserade gränssnitt för chatbottar. Antagandet är att förtroendet kan ökas, dels genom att addera röstutmatning till chatbotten och dels genom att text-till-röst-syntesen ges hög kvalité. Först introduceras chatbottar och konceptet konversationsbaserade gränssnitt. Därefter definieras örtroende i en online-kontext. Baserat på detta definieras en modell för förtroende samt uppfattningsfaktorer för trovärdighet, lättanvändhet och risk. Ett onlineexperiment utfördes, där deltagare går igenom konversationscenarion med en chatbot medan röstutmatningen varieras. Därefter följde en undersökning ämnad att samla in data om uppfattningen om förtroendefaktorerna för ett scenario utan röst och två scenarion med olika talsyntes-kvalitéer. För att analysera den ordnade datan från undersökningen genomfördes Wilcoxon signedrank-testet, ett ickeparametriskt statistiskt test, för att jämföra förtroenden för de olika röstutmatningstyperna. Resultaten visar att addering av röstutmatningsmodalitet till ett konversationsbaserat chatbotsgränsnitt ökar användares förtroende för tjänsten. Vidare, antagandet att synteskvalitén har effekt på förtroendet kunde inte verifieras därför att resultaten inte är statistiskt signifikanta. Begränsningarna hos de använda metoderna diskuteras och förslag för framtida forskning läggs fram.

Trust is one of the attitudes that can affect the intentions and the behavior of a human using a system. Misusing a system can have safety- as well as economic consequences, this is why it is important that a user develops calibrated trust towards a system. In this report, the research question is: how much trust cross country skiers have towards a physical intelligent tutoring system (PITS)? Six biological males (age 24 to 50) roller skied on a mechanical treadmill and received feedback from the PITS on a TV-screen. Experience of using the PITS was evaluated with an instrument in a semi-structured interview. The instrument measured the participants overall perceived trust (OPT) for the system, and the participants were asked to further their thoughts about the statements. The data was transcribed, coded, and categorized in a thematic analysis. The result showed that a majority of the participants had low OPT for the PITS, and the thematic analysis showed that the minority with higher levels of OPT focused on the choice of an elite skier as the reference skier. One of the problems with the instrument was that it was developed for evaluation in long term usage, and not first time usage as in this study. The result of this report can be used for further development of the PITS and a reminder on why trust needs to be considered when creating user experiences.