Emotional Engagement with Embodied Agents
H.C. van Vugt, E.A. Konijn, J.F. Hoorn, A. Eliëns, I. Keur
Vrije Universiteit Amsterdam
response [4]. Relevance concerns the user’s evaluation of
the importance of the agent for his goals. When something
is not relevant, there is no emotional response. Valence
concerns the direction of the user’s emotions as related to
outcome expectancies, which can be either positive or
negative. For example, positive valence is evoked when the
system seems to help the user in completing a task
satisfactorily. In task contexts, these outcome expectancies
often concern efficiency, effort and effectiveness [1]; does
the user expect a positive outcome in terms of high
efficiency, low mental and physical effort, and desired
effect (user goals)? Next to relevance and valence, the
(dis)similarity between the agent and the perceiver also
contributes to the emotional responses, for example in
terms of gender, appearance, or goals. Thus, involvement
and distance are evoked in a comparison process in which
the embodied agent is compared to the user him/herself and
his/her goals.
ABSTRACT
In this paper we describe a model that gives an integrative
account of how engagement with embodied agents is a
trade-off between the parallel processes of involvement and
distance. Next to emotional engagement, the model
attempts to explain user’s behavioral intentions towards
embodied agents. Thus far, the user’s perspective in humanagent interaction is hardly studied in a systematic manner.
In the workshop we will present the preliminary results of a
first experimental study to test the validity of the model.
INTRODUCTION
In many empirical studies, the effects of embodied agents in
the human-agent interactions are evaluated in terms of user
performance, behavior, and user experiences [3]. Several
factors seem to influence the results, such as the agent’s
embodiment (e.g. gestures, realism) and mental capabilities
(e.g. personality, intelligence, social role). Overviews of
various relevant factors exist [e.g. 3, 6]. However, an
integrative theory or theoretical model that connects design
factors of embodied agents with user emotional engagement
and user’s behavioral intentions is lacking thus far. The aim
of the present study is to test a newly developed theoretical
model. This model is able to explain emotional engagement
and user’s behavioral intentions with embodied agents by
looking into underlying cognitive and emotional processes
that are activated when users confront such an agent.
Multiple experiments are designed to test the validity of the
model. We expect that the model will be advantageous for
the HCI field, particularly the embodied agent community,
because it allows (1) a systematic investigation of relevant
factors, (2) an investigation of the relative importance of
factors, (3) an integration of past research results, (4) a
deeper understanding of the psychological processes
underlying human-agent interaction, and (5) informing the
design of embodied agents.
Figure 1. Interactive PEFiC-model
The user evaluations concerning relevance, valence, and
similarity are based on what the user perceives. The
perceptual encoding stage consists of 4 main appraisal
domains. The model on perceiving and experiencing
fictional characters (PEFiC, [5]) assumes that the agent as a
character is perceived on the dimensions of ethics (goodbad), aesthetics (beautiful-ugly) and epistemics (realistic –
unrealistic) (dashed lines in Figure 1), based on earlier
studies with media figures. Affordances relate to the
perception of the agent as an interactive system for
achieving goals (drawn lines in Figure 1). Affordances
concern perceptions of possible interactions with the
embodied agent. For example, can I ask the agent a
question? Affordances will be judged in terms of relevance
EMOTIONAL ENGAGEMENT
Previous research [5] shows that user’s emotional
engagement exists of both involvement and distance
processes, which are parallel tendencies to approach or
avoid the agent. Involvement may include identification,
sympathy, warm feelings (I love him!), and distance may
include irritation, antipathy, or cold feelings (I hate him!).
These are two unipolar processes that are hypothesized to
influence the final satisfaction with the agent. How, then,
are involvement and distance established? Several
mechanisms can be described that underly user engagement
[5]. Based on emotion psychology, relevance and valence
are important contributors in evoking an emotional
1
and valence in light of user goals. According to the
Technology Acceptance Model (TAM), intentions to use
are good predictors of actual usage [2]. Such intentions are
likely to depend on relevance and valence judgments. In
addition, opinions of others (social norm) influence the
subjective perceptions and engagement processes. In sum,
we hypothesize that both specific aspects concerning the
agent’s embodiment as well as aspects concerning humancomputer interactions influence emotional engagement [7].
This resulted in the Interactive PEFiC-model (Figure 1) as
a model for future HCI-research.
secondary school were able to reconstruct the artwork
easily and without problems. In the negative valence
condition we told the participants that students in another
secondary school were not able to reconstruct the artwork.
After watching the demo, the participants were asked to fill
in a knowledge test and a user engagement questionnaire.
After completion, they received a small present. The next
day, their teachers explained that the actual reconstructing
of the artwork would not be necessary and appeared to be
too complicated.
EXPECTED RESULTS
STUDY
In this study, the effects of guidance offered by embodied
agents are tested. The main hypotheses are:
H1. Realistic agents evoke stronger positive (involvement)
and negative (distance) user engagement than without or
with an unrealistic agent.
H2. Positive valence results in stronger user engagement
than the negative condition, both for realistic and unrealistic
agents.
H3. Higher user involvement and lower distance leads to
higher satisfaction in human-agent interaction than lower
involvement and higher distance.
H4. Higher involvement and lower distance leads to better
task performance than lower involvement and higher
distance.
Thus, we will inspect the relations between type of agent,
outcome expectancies (valence), user engagement, and
actual task performance. Multivariate statistical analyses
will be used to test the validity of the hypotheses. The first
results will be presented in the workshop and discussed in
light of their theoretical contribution.
Materials. A 3D virtual environment in the cultural
heritage domain contains information about contemporary
art works, e.g. ‘Stone and Feather’ (Figure 2). This digital
dossier about an artwork served as the stimulus material in
our first experiment (Study 1). We used a demonstration of
the environment in different versions: without an agent vs. a
realistic (human-like) vs. an unrealistic (fantasy) agent.
Textual information on the characteristics of the artwork
(e.g. ‘The feather is an ostrich feather’) was given either as
a text balloon in the agent conditions, or text frame in the
no-agent condition.
Figure 2. Realistic agent with ‘Stone and Feather’
REFERENCES
1. Bevan, N. and Maclead, M. (1994) Usability measurement in
context. Behaviour and Information Technology, 13, 132-145.
Measurements. Structured questionnaires were used to
measure (1) user perceptions and engagement, and (2) task
performance. The questionnaires were pilot tested. A 40items engagement questionnaire included measures of
perceived realism, similarity, relevance, valence, user
involvement, distance, and satisfaction. Sample items from
the Epistemics scale include “The figure could exist in daily
life” and “I find the figure fake.” Task performance was
measured by the errors made in the knowledge test, in
which the artwork characteristics were questioned.
2. Davis, F. D. (1989) Perceived Usefulness, Perceived Ease of
Use, and User Acceptance of Information Technology MIS
Quarterly 19, 2, 319-339.
3. Dehn, D. M. and Van Mulken, S. (2000) The impact of animated
interface agents: A review of empirical research. International
Journal of Human-Computer Studies, 52, 1, 1-22.
4. Frijda, N. H. (1986) The Emotions. Cambridge University Press.
5. Konijn, E. A. and Hoorn, J. F. (2005) Some like it bad. Testing a
model for perceiving and experiencing fictional characters.
Media Psychology 7, 2, 107-144.
Procedure. At a Dutch secondary school, 6 classes of about
25 students each were asked to cooperate in research that
‘aimed at improving computer-mediated education’. They
were instructed to watch the demonstration and they were
told that we would return the next day to see how well they
could reconstruct the piece of art. We further varied the
outcome expectations (valence) of this reconstruction by
manipulation of the instructions. In the positive valence
condition we told the participants that students in another
6. Ruttkay, Z., Dormann, C., and Noot, H. (2004). ECAs on a
common ground, a framework for design and evaluation. In
Ruttkay, Z. and Pelachaud, C., editors, From Brows till Trust:
Evaluating Embodied Conversational Agents, pages 27–66.
Kluwer.
7. Van Vugt, H.C., Hoorn, J.F. and Konijn, E.A. (2004) Adapting
empathic agents to user experiences. In Proc. AAMAS 2004,
workshop on Empathic Agents.
2