Information Technology Reference
In-Depth Information
Robot [13], iCat [14] when their research focus is not on increasing realism of a
humanoid robot such as geminoids [8]. We believe providing research results on the
perception of cartoonish virtual agents' facial expressions is also meaningful in order
to minimize the effort to develop social robot's facial expressions.
We investigated cultural differences in using the eye and mouth regions as cues to
recognize the facial expressions of cartoonish agent faces between Hungary and
Japan. We conducted a web-based survey to confirm the following hypothesis. In
cartoonish faces, Japanese weigh facial cues in the eye regions more heavily than
Hungarians, who weigh facial cues in the mouth region more heavily than Japanese.
Section 2 describes the facial expression design and experiment design, section 3
describes the results, section 4 discusses the results, and section 5 concludes the
research.
2 Experiment
2.1 Design of Facial Expressions
Two Japanese designers designed the three agent faces shown in Fig. 1. Each face
design has neutral, happy, and sad expressions. The examples of the three original
facial expressions are shown in Fig. 2. The face and facial expressions were created
using CharToon [15], a design and animation tool for 2D cartoon faces. The facial
expressions were designed by taking the emotional expressions displayed in Ekman's
FACS (Facial Action Coding System) training material. The facial features were
discussed in case of happy and sad expression [16].
Pre-evaluation of the original expressions was conducted by ten Japanese and eight
Hungarians to validate that each expression conveyed the intended emotions of the
designer. The static images of happy and sad expressions of the three face designs
were shown randomly to the evaluators after showing the neutral expression in each
session. They were asked to select the perceived emotion of the each expression
(happy or sad expression) from the following four adjectives: happy, sad, surprised,
fear. They wrote an adjective if they don't find appropriate adjectives from the four
provided. As a result of the pre-evaluation, all the original face designs had higher
than 90% recognition accuracy among Japanese, higher than 85% among Hungarians,
although we used cartoon faces and facial expressions designed by Japanese. Thus,
we can assume the happy and sad expressions correctly convey the intended emotions
in both countries. We also asked the perceived age of each agent face (discussed in
section 4).
We then created six static expressions per agent design by combining the eyes and
mouths. The six combinations are: happy eyes and neutral mouth (HN), happy eyes
and sad mouth (HS), neutral eyes and happy mouth (NH), neutral eyes and sad mouth
(NS), sad eyes and happy mouth (SH), and sad eyes and neutral mouth (SN). The total
number of combined facial expressions is 18 (six expressions x three agents). Fig. 3
shows the six combined expressions created from the original expressions in Fig. 2.
