Anton Nijholt

Eye gaze patterns in conversations: there is more to conversational agents than meets the eyes

In multi-agent, multi-user environments, users as well as agents should have a means of establishing who is talking to whom. In this paper, we present an experiment aimed at evaluating whether gaze directional cues of users could be used for this purpose. Using an eye tracker, we measured subject gaze at the faces of conversational partners during four-person conversations. Results indicate that when someone is listening or speaking to individuals, there is indeed a high probability that the person looked at is the person listened (p=88%) or spoken to (p=77%). We conclude that gaze is an excellent predictor of conversational attention in multiparty conversations. As such, it may form a reliable source of input for conversational systems that need to establish whom the user is speaking or listening to. We implemented our findings in FRED, a multi-agent conversational system that uses eye input to gauge which agent the user is listening or speaking to.

Turning shortcomings into challenges: Brain–computer interfaces for games

In recent years we have seen a rising interest in brain-computer interfacing for human-computer interaction and potential game applications. Until now, however, we have almost only seen attempts where BCI is used to measure the affective state of the user or in neurofeeedback games. There have hardly been any attempts to design BCI games where BCI is considered to be one of the possible input modalities that can be used to control the game. One reason may be that research still follows the paradigms of the traditional, medically oriented, BCI approaches. In this paper we discuss current BCI research from the viewpoint of games and game design. It is hoped that this survey will make clear that we need to design different games than we used to, but that such games can nevertheless be interesting and exciting.

Movement-based sports video games: Investigating motivation and gaming experience

Video game consoles that enable gamers to use active body movements are becoming increasingly popular. Yet, little is known about the influence of movement on how gamers experience such games. This study takes an exploratory approach, using different data collection methods. A theory about the relationship between body movement and gaming experience emerges through the systematic collection and analysis of data obtained from interviews, questionnaires, video observations and a motion capture system. A Grounded Theory analysis of the interviews reveals two distinct motivations (to achieve and to relax) with which gamers approach such games, together with two corresponding movement control strategies. Four movement-specific items are found to influence immersion in movement-based interaction: natural control, mimicry of movements, proprioceptive feedback, and physical challenge. These results are verified by exploiting the movement patterns of gamers playing the Nintendo Wii Boxing game. This theory others insights to game designers as to how to design future generations of movement-based games. Whilst a controller that leaves more space for appropriation can be appealing to a larger population, its design may fail to promote and motivate physical activity and emotional well-being.

Brain-Computer Interfacing and Games

Recently research into Brain-Computer Interfacing (BCI) applications for healthy users, such as games, has been initiated. But why would a healthy person use a still-unproven technology such as BCI for game interaction? BCI provides a combination of information and features that no other input modality can offer. But for general acceptance of this technology, usability and user experience will need to be taken into account when designing such systems. Therefore, this chapter gives an overview of the state of the art of BCI in games and discusses the consequences of applying knowledge from Human-Computer Interaction (HCI) to the design of BCI for games. The integration of HCI with BCI is illustrated by research examples and showcases, intended to take this promising technology out of the lab. Future research needs to move beyond feasibility tests, to prove that BCI is also applicable in realistic, real-world settings.

Human-Centred Intelligent Human Computer Interaction (HCI²): how far are we from attaining it?

A widely accepted prediction is that computing will move to the background, weaving itself into the fabric of our everyday living spaces and projecting the human user into the foreground. To realise this prediction, next-generation computing should develop anticipatory user interfaces that are human-centred, built for humans and based on naturally occurring multimodal human communication. These interfaces should transcend the traditional keyboard and mouse and have the capacity to understand and emulate human communicative intentions as expressed through behavioural cues, such as affective and social signals. This article discusses how far we are to the goal of human-centred computing and Human-Centred Intelligent Human-Computer Interaction (HCI2) that can understand and respond to multimodal human communication.

Emotional brain-computer interfaces

Research in Brain-Computer Interface (BCI) has significantly increased during the last few years. In addition to their initial role as assisting devices for the physically challenged, BCIs are now proposed for a wider range of applications. As in any HCI application, BCIs can also benefit from adapting their operation to the emotional state of the user. BCIs have the advantage of having access to brain activity which can provide significant insight into the users emotional state. This information can be utilized in two manners. 1) Knowledge of the influence of the emotional state on brain activity patterns can allow the BCI to adapt its recognition algorithms, so that the intention of the user is still correctly interpreted in spite of signal deviations induced by the subjects emotional state. 2) The ability to recognize emotions can be used in BCIs to provide the user with more natural ways of controlling the BCI through affective modulation. Thus, controlling a BCI by recollecting a pleasant memory can be possible and can potentially lead to higher information transfer rates. These two approaches of emotion utilization in BCI are elaborated in detail in this paper in the framework of non-invasive EEG based BCIs.

Multimodal Interactions with Agents in Virtual Worlds

In this chapter we discuss our research on multimodal interaction in a virtual environment. The environment we have developed can be considered as a ‘laboratory’ for research on multimodal interactions and multimedia presentation, where we have multiple users and various agents that help the users to obtain and communicate information. The environment represents a theatre. The theatre has been built using VRML (Virtual Reality Modeling Language) and it can be accessed through World Wide Web (WWW). This virtual theatre allows navigation input through keyboard function keys and mouse, but there is also a navigation agent which tries to understand keyboard natural language input and spoken commands. Feedback of the system is given using speech synthesis. We also have Karen, an information agent which allows a natural language dialogue with the user. In development are several talking faces for the different agents in the virtual world. We investigate how we can increase the user’s commitment to the environment and its agents by providing context and increasing the user’s feeling of ‘presence’ in the environment.

A survey of affective brain computer interfaces: principles, state-of-the-art, and challenges

Affective states, moods and emotions, are an integral part of human nature: they shape our thoughts, govern the behavior of the individual, and influence our interpersonal relationships. The last decades have seen a growing interest in the automatic detection of such states from voice, facial expression, and physiological signals, primarily with the goal of enhancing human-computer interaction with an affective component. With the advent of brain-computer interface research, the idea of affective brain-computer interfaces (aBCI), enabling affect detection from brain signals, arose. In this article, we set out to survey the field of neurophysiology-based affect detection. We outline possible applications of aBCI in a general taxonomy of brain-computer interface approaches and introduce the core concepts of affect and their neurophysiological fundamentals. We show that there is a growing body of literature that evidences the capabilities, but also the limitations and challenges of affect detection from neurophysiological activity.

Generation of Facial Expressions from Emotion Using a Fuzzy Rule Based System

We propose a fuzzy rule-based system to map representations of the emotional state of an animated agent onto muscle contraction values for the appropriate facial expressions. Our implementation pays special attention to the way in which continuous changes in the intensity of emotions can be displayed smoothly on the graphical face. The rule system we have defined implements the patterns described by psychologists and researchers dealing with facial expressions of humans, including rules for displaying blends of expressions.

Brain-computer interfaces for hci and games

In this workshop we study the research themes and the state-of-the-art of brain-computer interaction. Brain-computer interface research has seen much progress in the medical domain, for example for prosthesis control or as biofeedback therapy for the treatment of neurological disorders. Here, however, we look at brain-computer interaction especially as it applies to research in Human-Computer Interaction (HCI). Through this workshop and continuing discussions, we aim to define research approaches and applications that apply to disabled and able-bodied users across a variety of real-world usage scenarios. Entertainment and game design is one of the application areas that will be considered.