Evaluating humanoid embodied conversational agents in mobile guide applications

Evolution in the area of mobile computing has been phenomenal in the last few years. The exploding increase in hardware power has enabled multimodal mobile interfaces to be developed. These interfaces differ from the traditional graphical user interface (GUI), in that they enable a more “natural” communication with mobile devices, through the use of multiple communication channels (e.g., multi-touch, speech recognition, etc.). As a result, a new generation of applications has emerged that provide human-like assistance in the user interface (e.g., the Siri conversational assistant (Siri Inc., visited 2010)). These conversational agents are currently designed to automate a number of tedious mobile tasks (e.g., to call a taxi), but the possible applications are endless. A domain of particular interest is that of Cultural Heritage, where conversational agents can act as personalized tour guides in, for example, archaeological attractions. The visitors to historical places have a diverse range of information needs. For example, casual visitors have different information needs from those with a deeper interest in an attraction (e.g., - holiday learners versus students). A personalized conversational agent can access a cultural heritage database, and effectively translate data into a natural language form that is adapted to the visitor’s personal needs and interests. The present research aims to investigate the information needs of a specific type of visitors, those for whom retention of cultural content is important (e.g., students of history, cultural experts, history hobbyists, educators, etc.). Embodying a conversational agent enables the agent to use additional modalities to communicate this content (e.g., through facial expressions, deictic gestures, etc.) to the user. Simulating the social norms that guide the real-world human-to-human interaction (e.g., adapting the story based on the reactions of the users), should at least theoretically optimize the cognitive accessibility of the content. Although a number of projects have attempted to build embodied conversational agents (ECAs) for cultural heritage, little is known about their impact on the users’ perceived cognitive accessibility of the cultural heritage content, and the usability of the interfaces they support. In particular, there is a general disagreement on the advantages of multimodal ECAs in terms of users’ task performance and satisfaction over nonanthropomorphised interfaces. Further, little is known about what features influence what aspects of the cognitive accessibility of the content and/or usability of the interface. To address these questions I studied the user experiences with ECA interfaces in six user studies across three countries (Greece, UK and USA). To support these studies, I introduced: a) a conceptual framework based on well-established theoretical models of human cognition, and previous frameworks from the literature. The framework offers a holistic view of the design space of ECA systems b) a research technique for evaluating the cognitive accessibility of ECA-based information presentation systems that combine data from eye tracking and facial expression recognition. In addition, I designed a toolkit, from which I partially developed its natural language processing component, to facilitate rapid development of mobile guide applications using ECAs. Results from these studies provide evidence that an ECA, capable of displaying some of the communication strategies (e.g., non-verbal behaviours to accompany linguistic information etc.) found in the real-world human guidance scenario, is not affecting and effective in enhancing the user’s ability to retain cultural content. The findings from the first two studies, suggest than an ECA has no negative/positive impact on users experiencing content that is similar (but not the same) across different locations (see experiment one, in Chapter 7), and content of variable difficulty (see experiment two, in Chapter 7). However, my results also suggest that improving the degree of content personalization and the quality of the modalities used by the ECA can result in both effective and affecting human-ECA interactions. Effectiveness is the degree to which an ECA facilitates a user in accomplishing the navigation and information tasks. Similarly, affecting is the degree to which the ECA changes the quality of the user’s experience while accomplishing the navigation and information tasks. By adhering to the above rules, I gradually improved my designs and built ECAs that are affecting. In particular, I found that an ECA can affect the quality of the user’s navigation experience (see experiment three in Chapter 7), as well as how a user experiences narrations of cultural value (see experiment five, in Chapter 8). In terms of navigation, I found sound evidence that the strongest impact of the ECAs nonverbal behaviours is on the ability of users to correctly disambiguate the navigation of an ECA instructions provided by a tour guide system. However, my ECAs failed to become effective, and to elicit enhanced navigation or retention performances. Given the positive impact of ECAs on the disambiguation of navigation instructions, the lack of ECA-effectiveness in navigation could be attributed to the simulated mobile conditions. In a real outdoor environment, where users would have to actually walk around the castle, an ECA could have elicited better navigation performance, than a system without it. With regards to retention performance, my results suggest that a designer should not solely consider the impact of an ECA, but also the style and effectiveness of the question-answering (Q&A) with the ECA, and the type of user interacting with the ECA (see experiments four and six, in Chapter 8). I found that that there is a correlation between how many questions participants asked per location for a tour, and the information they retained after the completion of the tour. When participants were requested to ask the systems a specific number of questions per location, they could retain more information than when they were allowed to freely ask questions. However, the constrained style of interaction decreased their overall satisfaction with the systems. Therefore, when enhanced retention performance is needed, a designer should consider strategies that should direct users to ask a specific number of questions per location for a tour. On the other hand, when maintaining the positive levels of user experiences is the desired outcome of an interaction, users should be allowed to freely ask questions. Then, the effectiveness of the Q&A session is of importance to the success/failure of the user’s interaction with the ECA. In a natural-language question-answering system, the system often fails to understand the user’s question and, by default, it asks the user to rephrase again. A problem arises when the system fails to understand a question repeatedly. I found that a repetitive request to rephrase the same question annoys participants and affects their retention performance. Therefore, in order to ensure effective human-ECA Q&A, the repeat messages should be built in a way to allow users to figure out how to ask the system questions to avoid improper responses. Then, I found strong evidence that an ECA may be effective for some type of users, while for some others it may be not. I found that an ECA with an attention-grabbing mechanism (see experiment six, in Chapter 8), had an inverse effect on the retention performance of participants with different gender. In particular, it enhanced the retention performance of the male participants, while it degraded the retention performance of the female participants. Finally, a series of tentative design recommendations for the design of both affecting and effective ECAs in mobile guide applications in derived from the work undertaken. These are aimed at ECA researchers and mobile guide designers

Evaluating an intelligent Q&A system for mobile cultural learning

The paper presents a user study designed to evaluate the impact of an intelligent Q&A system for mobile cultural learning on the user’s subjective impressions and retention performance. We have chosen a recent pedagogical framework for mobile learning as a theoretical foundation for this work and designed our system accordingly. In particular, our Q&A system enables individual learners to interact with unknown cultural content under simulated mobile conditions in a well-organised and structured manner using natural language. To investigate the impact of the Q&A system on the participants’ retention of cultural content, we compared two variations of the Q&A system in the lab under simulated mobile conditions. The systems differed both in terms of the approach for processing natural language and style of a Q&A session. Below, we present the results of the study and a series of design recommendations that should aid in the development of more robust Q&A models for mobile cultural systems

Evaluating the impact of multimodal Collaborative Virtual Environments on user’s spatial knowledge and experience of gamified educational tasks

Several research projects in spatial cognition have suggested Virtual Environments (VEs) as an effective way of facilitating mental map development of a physical space. In the study reported in this paper, we evaluated the effectiveness of multimodal real-time interaction in distilling understanding of the VE after completing gamified educational tasks. We also measure the impact of these design elements on the user’s experience of educational tasks. The VE used reassembles an art gallery and it was built using REVERIE (Real and Virtual Engagement In Realistic Immersive Environment) a framework designed to enable multimodal communication on the Web. We compared the impact of REVERIE VG with an educational platform called Edu-Simulation for the same gamified educational tasks. We found that the multimodal VE had no impact on the ability of students to retain a mental model of the virtual space. However, we also found that students thought that it was easier to build a mental map of the virtual space in REVERIE VG. This means that using a multimodal CVE in a gamified educational experience does not benefit spatial performance, but also it does not cause distraction. The paper ends with future work and conclusions and suggestions for improving mental map construction and user experience in multimodal CVEs

Evaluating the impact of embodied conversational agents (ECAs) attentional behaviors on user retention of cultural content in a simulated mobile environment

The paper presents an evaluation study of the impact of an ECA’s attentional behaviors using a custom research method that combines facial expression analysis, eye-tracking and a retention test. The method provides additional channels to EEG-based methods for the study of user attention and emotions. In order to validate the proposed approach, two tour guide applications were created with an embodied conversational agent(ECA) that presents cultural content about a real-tourist attraction. The agent simulates two attention-grabbing mechanisms - humorous and serious to attract the users’ attention. A formal study was conducted to compare two tour guide applications in the lab. The data collected from the facial expression analysis and eye-tracking helped to explain particularly good and bad performances in retention tests. In terms of the study results, strong quantitative and qualitative evidence was found that an ECA should not attract more attention to itself than necessary, to avoid becoming a distraction from the flow of the content. It was also found that the ECA had an inverse effect on the retention performance of participants with different gender and their use on computer interfaces is not a good idea for elderly users

An empirical study on the effects of embodied conversational agents on user retention performance and perception in a simulated mobile environment

The paper presents a user study designed to examine the impact of the presence of a multimodal ECA on the user’s ability to retain content of cultural value with variable degree of difficulty (i.e., technical and simple content). The study was conducted in the lab, using a high resolution panorama representing four locations in an archaeological attraction. The content participants perceived differed both in terms of complexity and length. Participants interacted with an ECA-based system and then with a non-ECA system that provided content about popular locations in the attraction. Results indicate that participants who used the system with the ECA retained content of variable difficulty more consistently, than those who used the system without the ECA. However, we also found that if text is added as an additional output modality to an ECA-based information system it can positively impact the perception of the technical content, which can potentially lead to enhanced retention of technical content

A Framework for Research in Gamified Mobile Guide Applications using Embodied Conversational Agents (ECAs)

Mobile Guides are mobile applications that provide players with local and location-based services (LBS), such as navigation assistance, where and when they need them most. Advances in mobile technologies in recent years have enabled the gamification of these applications, opening up new opportunities to transfer education and culture through game play. However, adding traditional game elements such as PBLs (points, badges, and leaderboards) alone cannot ensure that the intended learning outcomes will be met, as the player’s cognitive resources are shared between the application and the surrounding environment. This distribution of resources prevents players from easily immersing themselves into the educational scenario. Adding artificial conversational characters (ECAs) that simulate the social norms found in real-life human-to-human guide scenarios has the potential to address this problem and improve the player’s experience and learning of cultural narratives [1]. Although significant progress has been made towards creating game-like mobile guides with ECAs ([2], [3]), there is still a lack of a unified framework that enables researchers and practitioners to investigate the potential effects of such applications to players and how to approach the concepts of player experience, cognitive accessibility and usability in this context. This paper presents a theoretically-well supported research framework consisted of four key components: differences in players, different features of the gamified task, aspects of how the ECA looks, sound or behaves and different mobile environments. Furthermore, it provides based on this framework a working definition of what player experience, cognitive accessibility and usability are in the context of game-like mobile guide applications. Finally, a synthesis of the results of six empirical studies conducted within this research framework is discussed and a series of design guidelines for the effective gamification of mobile guide applications using ECAs are presented. Results show that an ECA can positively affect the quality of the player’s experience, but it did not elicit better player retention of cultural narratives and navigation of routes

The impact of multimodal collaborative virtual environments on learning: A gamified online debate

Online learning platforms are integrated systems designed to provide students and teachers with information, tools and resources to facilitate and enhance the delivery and management of learning. In recent years platform designers have introduced gamification and multimodal interaction as ways to make online courses more engaging and immersive. Current Web-based platforms provide a limited degree of immersion in learning experiences, thereby diminishing potential learning impact. To improve immersion, it is necessary to stimulate some or all the human senses by engaging users in an environment that perceptually surrounds them and allows intuitive and rich interaction with other users and its content. Learning in these collaborative virtual environments (CVEs) can be aided by increasing motivation and engagement through the gamification of the educational task. This rich interaction that combines multimodal stimulation and gamification of the learning experience has the potential to draw students into the learning experience and improve learning outcomes. This paper presents the results of an experimental study designed to evaluate the impact of multimodal real-time interaction on user experience and learning of gamified educational tasks completed in a CVE. Secondary school teachers and students participated in the study. The multimodal CVE is an accurate reconstruction of the European Parliament in Brussels, developed using the REVERIE (Real and Virtual Engagement In Realistic Immersive Environment) framework. In the study, we compared the impact of the VR parliament to a non-multimodal control (an educational platform called Edu-Simulation) for the same educational tasks. Our results show that the multimodal CVE improves student learning performance and aspects of subjective experience when compared to the non-multimodal control. More specifically it resulted in a more positive effect on the ability of the students to generate ideas compared to a non-multimodal control. It also facilitated a sense of presence (strong emotional and a degree of spatial) for students in the VE. The paper concludes with a discussion of future work that focusses on combining the best features of both systems in a hybrid system to increase its educational impact and evaluate the prototype in real-world educational scenarios