Psychology

Research investigating the influence and character of nonverbal leader displays has been carried out in a systematic fashion since the early 1980s, yielding growing insight into how viewers respond to the televised facial display behavior of politicians. This article reviews the major streams of research in this area by considering the key ethological frameworks for understanding dominance relationships between leaders and followers and the role nonverbal communication plays in politics and social organization. The analysis focuses on key categories of facial display behavior by examining an extended selection of published experimental studies considering the influence of nonverbal leader behavior on observers, the nature of stimuli shown to research participants, range of measures employed, and make-up of participant pools. We conclude with suggestions for future research.

Niedenthal et al’s classification of smiles erroneously conflates psychological mechanisms and adaptive functions. This confusion weakens the rationale behind the types of smiles they chose to individuate, and it obfuscates the distinction between the communicative versus denotative nature of smiles and the role of perceived-gaze direction in emotion recognition.

The evidence that sociality is a central aspect of smiling behaviour fits rather nicely with evolutionary hypotheses that humans developed adaptations to face selective pressures imposed by increasing social complexity. The present paper gives a summary of recent data on the impact of various aspects of sociality on the frequency of smiling. It is argued that different forms of smiles could have different functions in social relationships. While deliberate smiles could be used in formal or hierarchical contexts; spontaneous, or Duchenne, smiles could function to advertise individual dimensions that are relevant to the development of cooperative relationships. Finally the role of emotion is discussed in connection to the physiological costs imposed on social signaling to ensure reliability.

Although research suggests that different types of smiles have different meaning, and possibly different functions, observational evidence to support that claim is relatively rare. The present study reports ethological observations on the frequency of smiling and laughter during naturally occurring dyadic interactions taking place in bars and cafés. Smiles were classified along two dimensions: spontaneous/deliberate and open/closed. Younger individuals displayed more laughter, spontaneous smiles and open smiles. People tended to smile more to individuals of their own sex and this was particularly salient for closed smiles, which appeared at significantly higher rates in male dyads. Different forms of smiles and laughter also varied with the behavioural context, characterized in this study by conversation time, displacement activities, and body contacts. The present findings also suggest that laughter plays a role in regulating partner's speech. This article supports the assumption that different forms of smiles have different functions in social relationships: Open and spontaneous smiles could be related to affiliation/bonding; whereas closed and deliberate smiles could be related to the regulation of status based social interactions. The relationship between smiling and laughter is also discussed.

Social relationships in bonnet macaques (Macaca radiata) are reflected by exten- sive affiliative and agonistic interactions between all individuals of different age, sex, dominance rank, and kinship groups. Adult females form strong linear domi- nance hierarchies with their daughters occupying ranks just below their mothers, which is typical among various Cecopithecine species. A habituated group of bonnet macaque (Macaca radiata diluata) in the village of Surakkadu near the town of Sirkali (Nagapattinam District, Tamil Nadu State, south India), was observed to re- cord data on social behaviour. Females mainly initiated more affiliative behaviours than males. There were significant inter-sexual differences for grooming behaviour, grooming invitation and huddling and females involved more in those interactions. However, males displayed more homosexual behaviours such as touching genitals and presentation while females seldom mounted each other.

The burgeoning field of social signal processing (SSP) is in great need of a theoretical framework to guide future research activities. The present article aims at bringing forward two areas of research that devoted considerable efforts to the understanding of social behaviour: ethology and social psychology. With a long tradition in the study of animal signals, ethology and evolutionary biology have developed theoretical concepts to account for the functional significance of signalling. For example, the consideration of divergent selective pressures responsible for the evolution of signalling and social cognition emphasized the importance of two classes of indicators: informative cues and communicative signals. Social psychology, on the other hand, reports investigations about emotional expression and interpersonal relationships, with a focus on the mechanisms underlying the production and interpretation of social signals and cues. All in all, the concepts developed in these two fields of research should bring invaluable insight to the development of SSP.

We test Ekman's (2003) suggestion that movements of a small number of "reliable facial muscles" are particularly trustworthy cues to experienced emotion as they tend to be difficult to produce voluntarily. Based on theoretical predictions, two subsets of facial action units (AUs) were identified: reliable AUs and versatile AUs. A survey on the controllability of facial AUs confirmed that reliable AUs seem indeed more difficult to control than versatile AUs, though the distinction between the two sets of AUs should be understood as a difference in degree of controllability rather than a discrete categorization. Professional actors enacted a series of emotional states using method acting techniques and their facial expressions were rated by independent judges. The effect of the two subsets of AUs (reliable AUs and versatile AUs) on identification of the emotion conveyed, its perceived authenticity, and perceived intensity was investigated. Activation of the reliable AUs had a stronger effect than that of versatile AUs on the identification, perceived authenticity, and perceived intensity of the emotion expressed. There was little evidence, however, for specific links between individual AUs and particular emotion categories. We conclude that reliable AUs may indeed convey trustworthy information about emotional processes but that most of these AUs are likely to be shared by several emotions, rather than providing information about specific emotions. This study also suggests that the issue of reliable facial muscles may generalize beyond the Duchenne smile.

Behavioral research has become increasingly concerned with the adaptive significance of facial expressions, which can be regarded as evolved social signals. In an attempt to uncover the function of smiling behavior, the assessment of various evolutionarily relevant traits was examined through people’s judgments of neutral and smiling photographs. Pictures were rated for ten attributes: attractiveness, generosity, trustworthiness, competitiveness, health, agreeableness, conscientiousness, extroversion, neuroticism, and openness to experience. Although smiling faces received higher scores on several dimensions, the difference in judgments between neutral and smiling varied with the sex composition of the sender-receiver dyad. Overall, smiling influenced men’s judgments in a larger extent than women’s, especially when faces were female. Our data show that smiling positively affects the perception of personality traits in a way that could be adaptive to the sender of the signal.

Automatic facial expression recognition has been an active topic in computer science for over two decades, in particular facial action coding system action unit (AU) detection and classification of a number of discrete emotion states from facial expressive imagery. Standardization and comparability have received some attention; for instance, there exist a number of commonly used facial expression databases. However, lack of a commonly accepted evaluation protocol and, typically, lack of sufficient details needed to reproduce the reported individual results make it difficult to compare systems. This, in turn, hinders the progress of the field. A periodical challenge in facial expression recognition would allow such a comparison on a level playing field. It would provide an insight on how far the field has come and would allow researchers to identify new goals, challenges, and targets. This paper presents a meta-analysis of the first such challenge in automatic recognition of facial expressions, held during the IEEE conference on Face and Gesture Recognition 2011. It details the challenge data, evaluation protocol, and the results attained in two subchallenges: AU detection and classification of facial expression imagery in terms of a number of discrete emotion categories. We also summarize the lessons learned and reflect on the future of the field of facial expression recognition in general and on possible future challenges in particular.

Abstract While detecting and interpreting temporal patterns of non-verbal behavioral cues in a given context is a natural and often unconscious process for humans, it remains a rather difficult task for computer systems. Nevertheless, it is an important one to achieve if the goal is to realise a naturalistic communication between humans and machines.

Abstract Automatic Facial Expression Recognition and Analysis, in particular FACS Action Unit (AU) detection and discrete emotion detection, has been an active topic in computer science for over two decades. Standardisation and comparability has come some way; for instance, there exist a number of commonly used facial expression databases. However, lack of a common evaluation protocol and lack of sufficient details to reproduce the reported individual results make it difficult to compare systems to each other.

Recent research has stressed the importance of using multimodal and dynamic features to investigate
the role of nonverbal behaviour in social perception. This paper examines the influence of low-level visual and auditory cues on the communication of agreement, disagreement, and the ability to convince others. In addition, we investigate whether the judgment of these attitudes depends on ratings of socio-emotional dimensions such as dominance, arousal, and valence. The material we used consisted of audio-video excerpts that represent statements of agreement and disagreement, as well as neutral utterances taken from political discussions. Each excerpt was rated on a number of dimensions: agreement, disagreement, dominance, valence, arousal, and convincing power in three rating conditions: audio-only, video-only, and audio-video. We extracted low-level dynamic visual features using optical flow. Auditory features consisted of pitch measurements, vocal intensity, and articulation rate. Results show that judges were able to distinguish statements of disagreement from agreement and neutral utterances on the basis of on nonverbal cues alone, in particular, when both auditory and visual information were present. Visual features were more influential when presented along with auditory features. Perceivers mainly used changes in pitch and the maximum speed of vertical movements to infer agreement and disagreement, and targets appeared more convincing when they showed consistent and rapid movements on the vertical plane. The effect of nonverbal features on ratings of agreement and disagreement was completely mediated by ratings of dominance, valence, and arousal, indicating that the impact of low-level audio-visual features on the perception of agreement and disagreement depends on the perception of fundamental socio-emotional dimensions.