Embodied agent features that maintain user attention The authors have identified four important embodied agent features that

are integral to maintaining users’ attention: the embodied agent’s rep-resentation, behaviour, voice and the interaction between the agent and application. These features are discussed in more detail below.

6.2.1 Embodied agent representation

Users’ first impressions of avatars, or embodied agents, usually depend on their ability to quickly ‘sum up’ the agent’s purpose or functionality.

Many lasting impressions are formed from the embodied agent’s visual appeal. Thus, the mission of these embodied agents is to show added value and retain the users’ attention quickly. In video games, for exam-ple, Gard (2000) indicates that the players’ first impression of an avatar often determines the way players will interact with the game. This first impression, then, is a matter of importance that has lasting effects for

the player and often even involves some subtle form of ‘seduction’ to win players’ acceptance and approval.

Fogg (2003) demonstrates how the recognizable names Disk Doctor and Win Doctor, associated with the Symantec Norton Utilities products, were not chosen by chance. In these examples, the use of the word ‘doc-tor’ calls to mind associations with intelligence, knowledge and expertise and therefore engenders user confidence. Disk Doctor and Win Doctor are more persuasive word choices than ‘Disk Helper’ or ‘Disk Assistant’

because a diagnosis made by an experienced doctor is more credible and comforting than the same one made by a junior doctor or assistant. When examples of expertise are represented visually in an embodied agent, these notions could be conveyed through the visible age of the charac-ter, accessories such as glasses, posture, gait and purposeful gestures.

Finally, the voice or name (or nickname) associated with the embodied agent also provides meaningful cues. The name ‘Living Actor^TM’ was chosen with the intended purpose of representing the embodied agent.

The use of the word ‘living’ suggests an entity that is real, intuitive and autonomous. The use of the word ‘actor’ suggests an ability to convey emotions, gestures, mood, voice and personality naturally and expertly.

Thus the name Living Actor^TMis meant to remind the user of genuine, human interaction. Therefore the representation of the agent will be the means by which designers initially capture users’ attention. Depend-ing on the audience, the embodied agent’s mission and the goal of the application or platform that will be the environment in which the avatar resides, embodied agents can take many forms. For example, they can be realistic or cartoonish, consist of a talking head, upper body or full body, be human, animal, take on an abstract form or be an object. Embodied agents don’t necessarily have to be human characters in order to capture one’s attention successfully. Even very early applications of embodied agents were concerned with these aspects of visual representation. For instance, Microsoft launched a genie character in 1996 which De Rosis, De Carolis and Pizzutilo (1999) defined as an extraverted agent with a dominant personality. Its physical appearance was intended to be pow-erful, and its blue colour was intended to be calming. As in the examples above, representative features are often chosen to encourage users to trust the interface functionality.

While modern embodied agents come in a variety of forms, as shown infigure 6.1(see plate), the authors have found that whether the embod-ied agents are realistic, anthropomorphized or cartoonish, users expect a high-quality human-like connection. Embodied agents build rapport and connect with users when their behaviours, gestures and interactions are genuine. Humans thrive on social interaction that is genuine and

often seek to identify or find commonalities with interlocutors on several different levels (Raybourn2004).

An embodied agent can also exhibit different personalities or call to mind visual representations that may be familiar from childhood, teenage years or any happy times in one’s life. An example is the embodied agent Numix which was developed by Cantoche in 2003 for the new intranet of the French national TV station, France 2. The purpose and mission of the Numix character was to assist France 2 employees with the transition from traditional work practices to the adoption of new processes and digital technologies. Maintaining attention was necessary not only to train users on new processes, but also to ease users’ anxieties about change. As this sort of change is often painful for established, older employees, Cantoche needed to address the following question: What is the best design for an embodied agent whose purpose is to help diverse users (of different ages, educations, genders, ethnicities, etc.) adapt to a new technology and accept cultural change more easily?

Cantoche solved the problem for France 2 by creating an embodied agent whose representation encouraged creativity, light-heartedness and openness. Numix was not too ‘high tech’ and unapproachable but rather resembled well-known characters that appeal to most French people of all ages and was reminiscent of the smart, funny and widely popular French cartoon series of the early 1970s,Shadoks(Rouxel 2006). The Shadoks, created by Jacques Rouxel, are drawn with simple lines and feature characters that are neither human nor animal, but an amalga-mation of interesting shapes. The Numix embodied agent is represented through round shapes and soft, natural colours that contrast with the technical images and content of intranet. The spiral body and anten-nae of Numix pulsate as if he were breathing, thus communicating that he is a living, organic entity that inhabits a technical environment. By purposefully controlling Numix’s breathing in idle and other states, the embodied agent communicated to the user that he was alive and that the user was not alone in his exploration of new technical content.

By choosing to create a countercultural embodied agent that would be familiar to all users and a welcomed contrast to the very unfamiliar con-tent of the intranet, Cantoche brought the user closer to foreign materials and processes (Raybourn2004). Numix served as the interactional glue needed to ease the cultural change that the organization was undergoing.

As discussed above, the ability of the embodied agent to capture and sustain users’ attention is a result of a number of interaction strategies, such as the graphical aesthetic, technical quality, relevant behaviour and overall perceived added value. When executed correctly, a caricature of a dog can even be perceived as more intelligent than a caricature of a

human (Koda and Maes 1996). Numix is a real-world example of an embodied agent that captured the attention of users as a result of these interaction strategies.

6.2.2 Behaviour

Albert Mehrabian (1971) demonstrated that body movement comprises 55 per cent of nonverbal communication. Body gestures are especially important when helping users navigate complex content and contexts.

Living Actor^TMembodied agents are most often full-body avatars that leverage the full range of human capabilities for interpreting nonverbal communication by providing movement with purposeful intent, while the reinforcement of verbal communication improves retention. As shown in figure 6.2 (see plate), the full body can engage users by demonstrating posture, movement, emotion and personality.

Living Actor^TM avatar behaviours represent a complete departure from existing solutions due to a significant and unique innovation. Liv-ing Actor^TM uses a behavioural intelligence engine which endows the avatar with an autonomous existence, thereby allowing it to adjust its interaction to each user. This technology provides the intelligent vir-tual agent with unsurpassed automatic behaviours and expressiveness that enables it to engage in high-quality nonverbal communication that is essential to effective communication. The resulting automation also makes it possible to reduce the cost and production time of developing the embodied agent’s behaviours and interactions significantly.

As a Living Actor^TMavatar can be embedded directly in the applica-tion, the agent can gesture and point to specific content, as shown in figure 6.2. The avatar also orients the attention of the user to specific points and can keep users engaged throughout the dialogue process.

Now let us distinguish between two physical parts of the embodied agent, the face and the body. Humans feel an innate, genuine connection to other human faces. The embodied agent’s face is no exception to facilitating a genuine connection. The avatars use expressions to convey emotions, produce emotions within the user, draw attention to something or retain users’ attention. The avatar’s body actions, behaviours and gestures strongly contribute to the agent’s ability to be understood and correctly contextualized. The full-body actions complement the speech and create a holistic experience.

A person’s behaviours are as important in conveying language as his verbal communication. Embodied agents are understood by reading their body language or behaviour which gives them the characteristics needed to perform a mission credibly. Hogan (1996) discusses two strategies for

becoming a more convincing and persuasive interlocutor: make people like you, and make people believe you. He says the best way to be believed is to have coherent or congruent verbal and nonverbal communication.

Therefore, many researchers consider behaviour to be very important in all types of communication. Attention, for example, significantly benefits from nonverbal communication.

Years of research pertaining to eye movements has produced an abundance of literature on this subject. Early research was carried out by Dr Ernest Hildegard in the fifties. Gaze is a very important part of attention in terms of retaining one’s focus on a specific graphical area, but eye movements are also meaningful when observed in waiting phases. Research results indicate that people are likely to move their eyes temporarily to specific positions when remembering events, answering questions, talking to themselves, feeling something or visualizing future events. Eye motion is therefore the basis of various interpretations, and we must be careful when making use of it. Hogan is very precise in his research and defines six key positions or movements of the human eyes. For instance, he shows that looking at an upper right location is a sign of image visualization of a previously unknown situation. Hogan concludes that the knowledge we gain from the information provided by eye movements is a powerful communication tool. It is so powerful, in fact, that eye movements alone can contribute to and influence other people’s decisions. Appropriate eye movement signals confidence and attentiveness. A sustained look from the agent shows the user that an action is expected (Hogan1996).

With their experiment,The solar system, Cassell and Thorisson (1999) show that an embodied agent’s nonverbal behaviour, while improving the structure of conversation, can also make the actions of the system better understood. The study demonstrates that an embodied agent’s active or passive behaviours, without dialogue, allow people to understand that the system is waiting for an action.

However, embodied agent behaviours executed without purposeful intent might also hamper user understanding and appropriate attention allocation. For instance, distracting movements may unintentionally let users think that the system expects something from them. In addition, users may wonder what they have done right or wrong when they see an embodied agent blinking at them or performing automatic actions that cannot be understood. Consequently, programmers must ensure that embodied agents’ behaviours correspond to their purpose and the context of the situation. As Picard (2001) indicates, an animated paper clip which blinks any time you click on it is perceived as a person who protests by blinking when asked to leave your desktop.

Body language also provides rich information for human communi-cation. Human beings have an unlimited range of emotions that are easily understood through body language. In her book,Reading People, Dimitrius (1998) describes many human states and traits that can be easily identified through body language.

Body motion also allows an embodied agent to occupy the space or environment completely and draw in users’ attention. Embodied agents can point to elements using their hands, move, disappear and reappear.

The rhythm of the embodied agents’ movements is also a key factor in nonverbal communication. To persuade the user to execute an action, embodied agents can show that they are listening or waiting through slight movements and gaze. These subtle behaviours contrast with more active behaviours executed by embodied agents. By orienting the embodied agents’ body behaviours towards the user, moving a hand in the user’s direction or indicating intent with specific nonverbal emblems, embodied agents can prompt users to interact.

Many additional factors contribute to the extent to which we identify with others through communication. These include nonverbal visual cues that encode meaning, such as clothing, colours, gestures, behaviours and accessories. As embodied agents become more mainstream, users will want their personal avatars to reflect aspects of who they are or who they wish to be. Research has demonstrated that young persons and adults desire greater flexibility in designing and authoring avatars.

Cantoche Living Actor^TM allows users to encode specific meanings in embodied agents’ behaviours and visual features by endowing them with personalities unique to each individual character.

6.2.3 Voice

When the voice is involved the user memorizes the message better and is more receptive to information communicated confidently by the embod-ied agent. Hogan (1996) studembod-ied the confidence exhibited by a person according to vocal attributes. He demonstrates that significant features associated with different kinds of people can be transposed to embodied agents. For example, if the agent is a female, Hogan recommends low-ering the frequency of her voice by one octave in order for the voice to be perceived as more professional. According to research, women with high-frequency voices are considered as weak and boring. If the agent is a male, Hogan recommends making him more powerful and respectable by lowering his vocal frequency by half an octave.

Other vocal parameters, such as the rhythm of speech and changes in intonation, give the user confidence in the embodied agent and therefore

give the embodied agent persuasive power. A dominating character, for instance, uses a faster vocal rhythm than a submissive character.

‘It’s not what you say, it’s how you say it’ (Dimitrius 1998). Dimitrius shows how our everyday attitudes are not revealed by words but by the way we say them. According to her, two different dialogues take place in any conversation: the first uses words, and the second uses intonation.

When you ask somebody ‘how are you?’ and you hear ‘very well’, you do not automatically trust the answer. The tone of voice is pre-eminent in indicating whether the interlocutor is depressed, anxious, excited or something else. When you listen to the tone, the volume, the pace and other vocal features, you enter a nonverbal conversation where you can actually find the truth. These features are obviously less emphasized when using synthetic voices. Emotion in text-to-speech (TTS) is not as powerful as emotion in recorded speech (Nass, Foehr and Somoza 2000). However, even with the lack of emotion carried by synthetic voices compared with recorded voices, both may be productive.

Audio is enabled in the majority of modern computers, though it is not always possible to play it as desired in workplaces such as open-space offices; that is why the embodied agent’s speech may occasionally be written in a speech bubble like a comic strip’s dialogue balloon. In this case, the user’s gaze is distracted by the text in the balloon, and this lowers the impact of the agent’s behavioural language. However, this is still an interesting solution. Users are more attentive to an image of a human face with the mouth animated in synchrony with speech than to simple text (Sproullet al.1996).

6.2.4 Interaction between agent and application

Living Actor^TM avatars can be displayed in different formats or reside on different platforms (from PCs and mobile phones to set-top boxes for interactive television). These avatars are represented via superior graph-ics, and they can be distributed throughout various types of interfaces and devices depending on the technological specifications of the end-user. Therefore there are a number of possible interactions between the agent and application that can be used to direct the user’s attention.

Embodied agents inhabit the application, and as such designers must make a number of decisions regarding size and position within the space.

It is interesting to experiment with the size and attitudes of embod-ied agents. The Living Actor^TMavatar for the Louvre, described below and shown infigure 6.3(see plate), provides a resizeable embodied agent which can be moved over the interface and disappears when asked to. The agent Dominique-Vivant Denon helps both children and adults explore

the Louvre website. Dominique has specific attitudes and sizes that are purposefully varied to capture the internaut’s attention.

An interesting technique to capture users’ attention is the position of the embodied agent within the application. The first and simplest rule in filmmaking relates to the position of the subject within the frame. It is more harmonious and dynamic not to place the subject systematically right in the centre of the frame (Couchouron2004). All classical tech-niques of photography and cinematography, including viewing angles, may be applied to embodied agent visualization. A high angle shot tends to squeeze the character, whereas a low angle shot will have the opposite effect, strengthening a dominating personality.

All of these features are used in movies and cartoons. An excellent example that shows all the important features used to capture users’

attention is the cartoonDuck Amuck, directed by Chuck Jones in 1953 and selected as number two of ‘The 50 Greatest Cartoons: As Selected by 1,000 Animation Professionals’. In this cartoon, the star, Daffy Duck, is tormented by a sadistic, unseen animator (later revealed to be his friend and rival Bugs Bunny) who constantly changes Daffy’s location, clothing, voice, physical appearance and even shape.

In the example in figure 6.3 the embodied agent interacts with the application by calling users’ attention to details in the website content that the user would have otherwise missed or ignored. Dominique-Vivant Denon leans forward and whispers to the user as if sharing privileged information. The embodied agent’s gestures, behaviours and position within the application interact with the content to maintain the user’s attention.

In the sections above, the authors have discussed four general fea-tures important in attention research: the embodied agent’s representa-tion, behaviour, voice and interaction between the agent and application.

The subsequent discussion will focus on a detailed description of the attention-management technology and will include controlling embod-ied agents with graphs of states, attention-management scenarios and, finally, moving beyond scripting.

6.3 Special status of embodied agents in user interface