The Motivation of This Thesis

As reviewed in Chapter 2, some of the theories of emotion are useful in accounting for how humans recognize the emotional expressions of other people. On the basis of these theories it is possible to make predictions about the effect of a non-neutral contextual environment on the emotional judgments about robotic facial expressions. The predictions differ depending on the theory. According to Evolutionary Theories, there will be no contextual effect even in an emotional contextual environment - the message of a robotic EE (Expression of Emotion) encoded by the programmer is the one decoded by the receiver

(human subject). This is because, most of the convincing and believable robotic facial expressions were created with the help of the FACS, which rested on the assumptions drawn from Evolutionary Theories that the same message of an EE (Expression of Emotion) encoded by the sender (or expresser) is the one decoded by the receiver (or observer).

In contrast, Social Constructionist Theories strongly predict that the situational information will influence the recognition of synthetic robot facial expressions: even when they are based on the FACS system the message of a robotic EE (Expression of Emotion) encoded by the programmer is not always the same as that decoded by the receiver (human subject). This prediction is actually supported by an argument in (Russell et al. 2003) that, attributing a specific emotion to the sender becomes more complex (i.e., the receiver does not simply decode an emotional message in any simple, reflex-like manner), as even when the stimuli are facial expressions of basic emotions, the context which they occur (Carroll and Russell, 1996) can color the attribution. Furthermore, some non-classical theories of emotion also predict, though not strongly, there will be some sort of contextual effect on the recognition of robotic facial expressions. For instance, according to Niedenthal‘s theory of embodying emotion (Niedenthal et al. 2007), emotion congruence in perception strongly affects later reactivation and recognition of a facial expression of an emotion in another person. This argument predicts that congruent emotional contexts will help human subjects to recognize the robotic facial expressions better than the incongruent contexts. Even Perceptual Control Theory (PCT) claims that the disturbance from the environment could directly elicit an emotion of a living organism, which can lead to the prediction that a context can affect a person‘s emotional states and his/her appraisals of a robot‘s emotions.

As reviewed in Chapter 2, both the Embodied Appraisal Theory (e.g., Prinz, 2004a, 2004b) and the Social Functionalist Approach to Emotions (e.g., Keltner et al. 2006) claim that human emotions are both biologically based and socially constructed. Their concessions to Social Constructionist Theories enable them

to predict that the contexts will influence the recognition of synthetic robot facial expressions to some extent. However, no position is taken with regards to situational influence in Cognitive-appraisal Theories or Rolls‘s Theory of Emotion, as it is too difficult for them to take into account the social context in which the emotions are often embedded.

Some implications about which predictions were correct will be yielded from the experiments reported in this thesis, depending on whether or not a non- neutral contextual environment is found to have an influence on emotional judgments about robotic facial expressions. If no contextual influence on robot expressions is found, this would imply that the prediction made by the Evolutionary Theories was right and the one made by Social Constructionist Theories was wrong. However, if a contextual effect on robot expressions is found, this implies that the prediction made by Social Constructionist Theories was right but the one made by Evolutionary Theories was wrong. Although the predictions made by Niedenthal‘s theory of embodying emotion and Perceptual Control Theory (PCT) were not as strong as those of the Social Constructionist Theories, they would also be implied to be correct if a contextual influence was found. Some implications about whether or not robot faces are viewed in the same way as human faces could also be drawn depending on whether or not a contextual effect was found on robot expressions. If no contextual effect was found, this would indicate that the robot emotions were not socially constructed, then the implications is that robot faces are not viewed in the same way as human faces. This is because, as mentioned earlier, human emotions are both biologically based and socially constructed. In contrast, the occurrence of contextual effects would imply that human beings view the robot face in the same way as they view human faces.

The main motivation of the thesis is to see whether the context effects that have been obtained with human faces and avatars also apply to robot faces, and to investigate whether all forms of context also exert such an effect. To see the circumstances under which such contextual effects are likely to occur, investigations will also be conducted to establish whether the manner in which

the context and the robot head are presented (simultaneously or separately) is important in obtaining such a contextual effect. In other words, if context effects are found then the further questions to be investigated are (i) what kinds of context exert an effect? (ii) do contextual effects still occur when subjects have seen the robot face before? (ⅲ) does the manner in which the context and the robot face are presented (simultaneously or separately) make a difference? Where possible, the experimenter is also interested in exploring and differentiating between possible explanations of the reason context effects occur and do not occur, but it should be noted that this is not the preliminary motivation of the experiments reported here.