Emotion Induction and Facial Reactivity in a Wizard of Oz Experiment in Human-Computer Interaction

This study aimed to determine whether interacting with a simulated cognitive technical system could elicit different emotional responses, as indicated by facial expressions. Participants were presented with various challenging scenarios designed to elicit anger, frustration, fear, sadness, disappointment or general negative feelings. In a so-called 'Wizard of Oz' experiment, participants had to complete a solvable task while interacting with the simulated cognitive technical system. At two standardized points during the experiment, participants were confronted with an unexpected set of complex problems designed to elicit negative emotions (the weight limit barrier and the Waiuku barrier). These barriers were assessed by categorizing the participants' facial movements using the Facial Action Coding System(Ekman et al., 2002a). Emotion categorization was primarily based on the Emotional Facial Action Coding System (EMFACS(Friesen & Ekman, 1984)), but also incorporated prototypical Action Unit (AU) combinations as indicators.Analysis of 80 subjects revealed that there were hardly any full, prototypical facial expressions of emotion according to EMFACS. Studies that employed other methods to induce emotions usually found that only parts of prototypical emotions were displayed on the face. Our hypothesis regarding anger/frustration induction was not supported in either challenge situation. As hypothesized, unspecific negative affect and sadness/disappointment were significantly higher during the second challenge (the Waiuku barrier). The different emotions induced in the experiment, especially the high frequency of social smiling during the baseline condition, indicated that the technical system was capable of inducing emotions like humans can, and that it was treated like a person, albeit virtual.