An Adaptive Personality Model for ECAs

1
An Adaptive Personality Model for ECAs

• He Xiao ( ), Donald Reid, Andrew
  Marriott, E. K. Gulland
• Curtin University of Technology, Hayman Rd.
  Bentley, Western Australia.
• raytrace_at_cs.curtin.edu.au

Emotion and Mood Theories
Personality Theories
Personality represents those characteristics of
the individual that account for consistent
patterns of thinking, feeling and acting 32.
Psychology literature has been adopted by many
researchers 20, 34, 35 for modelling an ECAs
personality since psychologists have been
interested in personality for over one hundred
years. The first comprehensive theory of
personality was Freuds psychoanalytical theory
that attributed an individuals thoughts and
actions to the unconscious in regulating
behaviour 36. Social learning theories
explained differences in behaviour in terms of a
continuous reciprocal interaction between
cognitive, behaviour, and environmental
determinants 37. Traits are labels
Time duration is the main difference between
emotion, mood and personality 20, 22, 23.
Emotion is a momentary state and mood is more
static than emotion while personality changes
little over time. Researchers concerned with
facial, body and vocal emotion expressions, as
well as the appraisal of an agents emotions
based on its reactions to objects, events and
actions, have developed a number of emotional
models. Many of these employed the cognitive
appraisal model of OCC 29. The number of the 22
emotion types modelled in OCC
given to consistent aspects of personality and
are viewed as continuous dimensions 33. Trait
theorists assume that all people have a fixed
number of basic dimensions of personality
Eysenck and Eysencks 38 two basic dimensions
of personality, Cattell's 16 dimensions and Costa
McCraes 39 Five Factor Model and so on. Most
of the computational models of personality are
based on trait theories because the traits that
originate in everyday language are easy to
understand, and the conversion from trait
dimensions to a computational model is simple.
Beside psychologists, the computer science
researcher Rousseau 35 proposed 16 dimensions
of personality that are based on the processes
that intelligent agents usually perform. These
dimensions have been successfully applied in
Cybercafé and Buis ParleE 43. The modelling of
an ECAs personality is not limited to trait
theories. For example, the personality model of
Rousseau and Hayes-Roth 31 adopted the
psychology theories of social learning.
contrasts strongly with the 6 basic emotions of
Ekman 30 that are widely used for facial and
vocal expressions of an ECA. Our personality
model adopted OCC 22 emotions for appraisal and
then mapped them to Ekmans 6 basic emotions to
the TH system. Mood is explained by Vélasquez
25 as a low level of arousal within an
emotional system whilst emotion is explained as a
high level of arousal. Mood in this model have
three states bad mood, natural and good mood.
Personality Model (Psychology Level)
Social-Cognitive Theory
Social-cognitive perspective 36
Computational Personality Model
Computational Personality Model
Self-made ECAs
The Active Personality Model is implemented as OO
code that is loaded and executed at runtime on
both the server and client. The network channel
allows both system and user personality models to
be used interchangeably, with the model being
either sent from the server to the client or vice
versa. The ability to create and load client side
user personality models allows for transparent
research by disparate groups. The model will
remember user interactions through the use of
per-user files that contain learnt preferences
about how to interact with each user. The ECA
equipped with this model have emotion, mood,
variation of dialog, idle behaviour and self
control. It can communicate with user by facial
animation, gestures and emotional speech. It can
also design its appearance (change hair style,
lip colour etc) and act as a self-made ECA.
Evaluation Application
Evaluation Methodologies
User hi ECA You disappeared for a long
time! ECA Hello Mr Xiao,
You have a new mail from your friend length"short"/ Ivan Jackson about test
mail through mentor. User you
bastard ECA You have to improve your
language before improve your learning, He Xiao.
ECA (new mail coming) You have
a new mail from Tom Lee.
Hypotheses The personality model will enhance
the believability of ECA and make human computer
interaction more satisfying. Sub-hypothesis 1 An
ECA equipped with the personality model can
express emotion according to its personality
characteristics. Sub-hypothesis 2 A user can
identify the personality or the personality
characteristics of the ECA. In order to evaluate
the personality model in terms of these research
hypotheses, questionnaires and interviews will be
needed. The evaluation of a personality model is
not as easy as the evaluation of emotions since
personality can not be identified visually. A
long-term interactive scenario Email Agent has
been developed as evaluation application and
several experiments are needed. The evaluation
can be done by users who extensively interact
with the ECA and then answer the questionnaires.
Experiments and questionnaires will be designed
according to the requirement of the evaluation
which tightly relate to the hypotheses.
User hi ECA Yes boss ECA
New mail from Ivan Jackson User
you bastard ECA Same to you!
ECA (new mail coming) Who
cares!
Conclusion The design, implementation and
evaluation of a personality model for an ECA is
difficult, due to the human nature of
personality. The current study, especially the
evaluation method and the evaluation results,
should be beneficial to other researchers in this
relatively new area of ECA construction. Reference
s see the paper.