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

A two-step approach for interest estimation from gaze behavior in digital catalog browsing

While eye gaze data contain promising clues for inferring the interests of viewers of digital catalog content, viewers often dynamically switch their focus of attention. As a result, a direct application of conventional behavior analysis techniques, such as topic models, tends to be affected by items or attributes of little or no interest to the viewer. To overcome this limitation, we need to identify “when” the user compares items and to detect “which attribute types/values” reflect the user’s interest. This paper proposes a novel two-step approach to addressing these needs. Specifically, we introduce a likelihood-based short-term analysis method as the first step of the approach to simultaneously determine comparison phases of browsing and detect the attributes on which the viewer focuses, even when the attributes cannot be directly obtained from gaze points. Using probabilistic latent semantic analysis, we show that this short-term analysis step greatly improves the results of the subsequent step. The effectiveness of the framework is demonstrated in terms of the capability to extract combinations of attributes relevant to the viewer’s interest, which we call aspects, and also to estimate the interest described by these aspects

Is ‘Second Life’ taking over ‘Real Life’? Sociability and social interaction within the ‘Second Life’ environment: An electronic ethnographic study

Is it too early to make deductions about the impacts of Second Life (SL) (a virtual online environment) in Real Life (RL)? Should there be any concern of SL taking over RL or maybe not? In order to address these questions this study aims to examine ‘sociability’ within the SL virtual environment in order to determine the circumstances and the length that social interaction is encouraged within this virtual world; where ‘sociability’ should lie within the SL; and how the virtual residents facilitate the social interaction. Virtual Ethnography was employed over a period of 1.5 years in order to investigate social interaction of SL users. The findings of the research indicate people’s opinion differs since some perceive SL as an instrument that promotes sociability and others as a deterrent to social life. ‘In SL I have made such great friends, fell in love but have also been very badly hurt […]. People you love suddenly disappear’ said one of the respondents. Meaning that perceptions and experiences within the SL environment might resemble that of R

Gaze behavior during interaction with a virtual character in interactive storytelling

Y a-t-il une spécificité de l’archéologie des pays du Nord de l’Europe ? C’est à un archéologue danois, conservateur de l’Oldnordisk Museum de Copenhague, Christian Jürgensen Thomsen, que nous devons depuis 1836 le « système des trois âges », c’est-à-dire la distinction, fondatrice de la préhistoire européenne et au-delà, entre un âge de la pierre, un âge du bronze et un âge du fer. Dès le xviie siècle, le royaume de Suède avait institué un service archéologique national – il faut attendre le..

The Turning, Stretching and Boxing Technique: a Direction Worth Looking Towards

3D avatar user interfaces (UI) are now used for many applications, a growing area for their use is serving location sensitive information to users as they need it while visiting or touring a building. Users communicate directly with an avatar rendered to a display in order to ask a question, get directions or partake in a guided tour and as a result of this kind of interaction with avatar UI, they have become a familiar part of modern human-computer interaction (HCI). However, if the viewer is not in the sweet spot (defined by Raskar et al. (1999) as a stationary viewing position at the optimal 90° angle to a 2D display) of the 2D display, the 3D illusion of the avatar deteriorates, which becomes evident as the user’s ability to interpret the avatar’s gaze direction towards points of interests (PoI) in the user’s real-world surroundings deteriorates also. This thesis combats the above problem by allowing the user to view the 3D avatar UI from outside the sweet spot, without any deterioration in the 3D illusion. The user does not lose their ability to interpret the avatar’s gaze direction and thus, the user experiences no loss in the perceived corporeal presence (Holz et al., 2011) for the avatar. This is facilitated by a three pronged graphical process called the Turning, Stretching and Boxing (TSB) technique, which maintains the avatar’s 3D illusion regardless of the user’s viewing angle and is achieved by using head-tracking data from the user captured by a Microsoft Kinect. The TSB technique is a contribution of this thesis because of how it is used with an avatar UI, where the user is free to move outside of the sweet spot without losing the 3D illusion of the rendered avatar. Then each consecutive empirical study evaluates the claims of the TSB Technique are also contributions of this thesis, those claims are as follows: (1) increase interpretability of the avatar’s gaze direction and (2) increase perception of corporeal presence for the avatar. The last of the empirical studies evaluates the use of 3D display technology in conjunction with the TSB technique. The results of Study 1 and Study 2 indicate that there is a significant increase in the participants’ abilities to interpret the avatar’s gaze direction when the TSB technique is switched on. The survey from Study 1 shows a significant increase in the perceived corporeal presence of the avatar when the TSB technique is switched on. The results from Study 3 indicate that there is no significant benefit for participants’ when interpreting the avatar’s gaze direction with 3D display technology turned on or off when the TSB technique is switched on

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