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The goal of this research is to develop Animated Pedagogical Agents (APA) that can convey clearly perceivable emotions through speech, facial expressions and body gestures. In particular, the two studies reported in the paper investigated the extent to which modifications to the range of movement of 3 beat gestures, e.g., both arms synchronous outward gesture, both arms synchronous forward gesture, and upper body lean, and the agent‘s gender have significant effects on viewer’s perception of the agent’s emotion in terms of valence and arousal. For each gesture the range of movement was varied at 2 discrete levels. The stimuli of the studies were two sets of 12-s animation clips generated using fractional factorial designs; in each clip an animated agent who speaks and gestures, gives a lecture segment on binomial probability. 50% of the clips featured a female agent and 50% of the clips featured a male agent. In the first study, which used a within-subject design and metric conjoint analysis, 120 subjects were asked to watch 8 stimuli clips and rank them according to perceived valence and arousal (from highest to lowest). In the second study, which used a between-subject design, 300 participants were assigned to two groups of 150 subjects each. One group watched 8 clips featuring the male agent and one group watched 8 clips featuring the female agent. Each participant was asked to rate perceived valence and arousal for each clip using a 7-point Likert scale. Results from the two studies suggest that the more open and forward the gestures the agent makes, the higher the perceived valence and arousal. Surprisingly, agents who lean their body forward more are not perceived as having higher arousal and valence. Findings also show that female agents’ emotions are perceived as having higher arousal and more positive valence that male agents’ emotions.
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Measuring the effects of co-location on emotion perception in shared virtual environments: An ecological perspective
Inferring emotions from others’ non-verbal behavior is a pervasive and fundamental task in social interactions. Typically, real-life encounters imply the co-location of interactants, i.e., their embodiment within a shared spatial-temporal continuum in which the trajectories of the interaction partner’s Expressive Body Movement (EBM) create mutual social affordances. Shared Virtual Environments (SVEs) and Virtual Characters (VCs) are increasingly used to study social perception, allowing to reconcile experimental stimulus control with ecological validity. However, it remains unclear whether display modalities that enable co-presence have an impact on observers responses to VCs’ expressive behaviors. Drawing upon ecological approaches to social perception, we reasoned that sharing the space with a VC should amplify affordances as compared to a screen display, and consequently alter observers’ perceptions of EBM in terms of judgment certainty, hit rates, perceived expressive qualities (arousal and valence), and resulting approach and avoidance tendencies. In a between-subject design, we compared the perception of 54 10-s animations of VCs performing three daily activities (painting, mopping, sanding) in three emotional states (angry, happy, sad)—either displayed in 3D as a co-located VC moving in shared space, or as a 2D replay on a screen that was also placed in the SVEs. Results confirm the effective experimental control of the variable of interest, showing that perceived co-presence was significantly affected by the display modality, while perceived realism and immersion showed no difference. Spatial presence and social presence showed marginal effects. Results suggest that the display modality had a minimal effect on emotion perception. A weak effect was found for the expression “happy,” for which unbiased hit rates were higher in the 3D condition. Importantly, low hit rates were observed for all three emotion categories. However, observers judgments significantly correlated for category assignment and across all rating dimensions, indicating universal decoding principles. While category assignment was erroneous, though, ratings of valence and arousal were consistent with expectations derived from emotion theory. The study demonstrates the value of animated VCs in emotion perception studies and raises new questions regarding the validity of category-based emotion recognition measures.
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- Award ID(s):
- 1907807
- PAR ID:
- 10477502
- Publisher / Repository:
- Frontiers
- Date Published:
- Journal Name:
- Frontiers in Virtual Reality
- Volume:
- 4
- ISSN:
- 2673-4192
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/frvir.2023.1032510
