[A model of two-dimensional placement of the facial expressions of emotion].

It is a fundamental question whether facial expressions are processed categorically or continuously in the multidimensional space. According to Young, Rowland, Calder, Etcoff, Seth, and Perrett (1997), two-dimensional model predicts that: (i) transitions between expressions should be continuous, and (ii) at least some transitions between expressions should pass through a central neutral region or a region corresponding to a third emotion. We investigated this issue using schematic facial expressions which were used by Yamada (1993). We measured the difference between the neutral and each of six facial stimuli with basic expressions and created opposite faces with reference to the neutral face (100% (original, e.g. happy), 50%, 0% (neutral), -50%, -100% (opposite, e.g. unhappy), for each expression). Subjects rated the affective value of these stimuli. The configuration of four emotional stimuli showed that each stimulus (100%) passed through the neutral face and reached the opposite face (-100%) except for the disgust and fear. This result supports, at least partially, the two-dimensional model of face perception.