Sparsity in Dynamics of Spontaneous Subtle Emotions: Analysis \& Application

Spontaneous subtle emotions are expressed through micro-expressions, which are tiny, sudden and short-lived dynamics of facial muscles; thus poses a great challenge for visual recognition. The abrupt but significant dynamics for the recognition task are temporally sparse while the rest, irrelevant dynamics, are temporally redundant. In this work, we analyze and enforce sparsity constrains to learn significant temporal and spectral structures while eliminate irrelevant facial dynamics of micro-expressions, which would ease the challenge in the visual recognition of spontaneous subtle emotions. The hypothesis is confirmed through experimental results of automatic spontaneous subtle emotion recognition with several sparsity levels on CASME II and SMIC, the only two publicly available spontaneous subtle emotion databases. The overall performances of the automatic subtle emotion recognition are boosted when only significant dynamics are preserved from the original sequences.Comment: IEEE Transaction of Affective Computing (2016

Are there nonverbal cues to commitment? An exploratory study using the zero-acquaintance video presentation paradigm

Altruism is difficult to explain evolutionarily if subtle cheaters exist in a population (Trivers, 1971). A pathway to the evolutionary maintenance of cooperation is nonverbal altruist-detection. One adaptive advantage of nonverbal altruist-detection is the formation of trustworthy division of labour partnerships (Frank, 1988). Three studies were designed to test a fundamental assumption behind altruistic partner preference models. In the first experiment perceivers (blind with respect to target altruism level) made assessments of video-clips depicting self-reported altruists and self-reported non-altruists. Video-clips were designed with attempts to control for attractiveness, expressiveness, role-playing ability, and verbal content. Overall perceivers rated altruists as more “helpful” than non-altruists. In a second experiment manipulating the payoffs for cooperation, perceivers (blind with respect to payoff condition and altruism level) assessed altruists who were helping others as more “concerned” and “attentive” than non-altruists. However perceivers assessed the same altruists as less “concerned” and “attentive” than non-altruists when the payoffs were for self. This finding suggests that perceivers are sensitive to nonverbal indicators of selfishness. Indeed the self-reported non-altruists were more likely than self-reported altruists to retain resources for themselves in an objective measure of cooperative tendencies (i.e. a dictator game). In a third study altruists and non-altruists’ facial expressions were analyzed. The smile emerged as a consistent cue to altruism. In addition, altruists exhibited more expressions that are under involuntary control (e.g., orbicularis oculi) compared to non-altruists. Findings Are there nonverbal cues to commitment? suggest that likelihood to cooperate is signaled nonverbally and the putative cues may be under involuntary control as predicted by Frank (1988)

Facial Mimicry of Spontaneous and Deliberate Duchenne and Non-Duchenne Smiles

Increasing evidence suggests that Duchenne (D) smiles may not only occur as a sign of spontaneous enjoyment, but can also be deliberately posed. The aim of this paper was to investigate whether people mimic spontaneous and deliberate D and non-D smiles to a similar extent. Facial EMG responses were recorded while participants viewed short video-clips of each smile category which they had to judge with respect to valence, arousal, and genuineness. In line with previous research, valence and arousal ratings varied significantly as a function of smile type and elicitation condition. However, differences in facial reactions occurred only for smile type (i.e., D and non-D smiles). The findings have important implications for questions relating to the role of facial mimicry in expression understanding and suggest that mimicry may be essential in discriminating among various meanings of smiles

Chimpanzee faces under the magnifying glass: emerging methods reveal cross-species similarities and individuality

Independently, we created descriptive systems to characterize chimpanzee facial behavior, responding to a common need to have an objective, standardized coding system to ask questions about primate facial behaviors. Even with slightly different systems, we arrive at similar outcomes, with convergent conclusions about chimpanzee facial mobility. This convergence is a validation of the importance of the approach, and provides support for the future use of a facial action coding system for chimpanzees,ChimpFACS. Chimpanzees share many facial behaviors with those of humans. Therefore, processes and mechanisms that explain individual differences in facial activity can be compared with the use of a standardized systems such asChimpFACSandFACS. In this chapter we describe our independent methodological approaches, comparing how we arrived at our facial coding categories. We present some Action Descriptors (ADs) from Gaspar’s initial studies, especially focusing on an ethogram of chimpanzee and bonobo facial behavior, based on studies conducted between 1997 and 2004 at three chimpanzee colonies (The Detroit Zoo; Cleveland Metroparks Zoo; and Burger’s Zoo) and two bonobo colonies (The Columbus Zoo and Aquarium; The Milwaukee County Zoo). We discuss the potential significance of arising issues, the minor qualitative species differences that were found, and the larger quantitative differences in particular facial behaviors observed between species, e.g., bonobos expressed more movements containing particular action units (Brow Lowerer, Lip Raiser, Lip Corner Puller) compared with chimpanzees. The substantial interindividual variation in facial behavior within each species was most striking. Considering individual differences and the impact of development, we highlight the flexibility in facial activity of chimpanzees. We discuss the meaning of facial behaviors in nonhuman primates, addressing specifically individual attributes of Social Attraction, facial expressivity, and the connection of facial behavior to emotion. We do not rule out the communicative function of facial behavior, in which case an individual’s properties of facial behavior are seen as influencing his or her social life, but provide strong arguments in support of the role of facial behavior in the expression of internal states