Interpersonal Synchrony: A Survey of Evaluation Methods across Disciplines <s> Multidisciplinary Need for Synchrony Assessment <s> The ability to understand and manage social signals of a person we are communicating with is the core of social intelligence. Social intelligence is a facet of human intelligence that has been argued to be indispensable and perhaps the most important for success in life. This paper argues that next-generation computing needs to include the essence of social intelligence - the ability to recognize human social signals and social behaviours like turn taking, politeness, and disagreement - in order to become more effective and more efficient. Although each one of us understands the importance of social signals in everyday life situations, and in spite of recent advances in machine analysis of relevant behavioural cues like blinks, smiles, crossed arms, laughter, and similar, design and development of automated systems for social signal processing (SSP) are rather difficult. This paper surveys the past efforts in solving these problems by a computer, it summarizes the relevant findings in social psychology, and it proposes a set of recommendations for enabling the development of the next generation of socially aware computing. <s> BIB001 </s> Interpersonal Synchrony: A Survey of Evaluation Methods across Disciplines <s> Multidisciplinary Need for Synchrony Assessment <s> Gaze following is a key component of human social cognition. Gaze following directs attention to areas of high information value and accelerates social, causal, and cultural learning. An issue for both robotic and infant learning is whose gaze to follow. The hypothesis tested in this study is that infants use information derived from an entity's interactions with other agents as evidence about whether that entity is a perceiver. A robot was programmed so that it could engage in communicative, imitative exchanges with an adult experimenter. Infants who saw the robot act in this social-communicative fashion were more likely to follow its line of regard than those without such experience. Infants use prior experience with the robot's interactions as evidence that the robot is a psychological agent that can see. Infants want to look at what the robot is seeing, and thus shift their visual attention to the external target. <s> BIB002
T HE need for a multidisciplinary approach to assessing synchrony is evident at the interface of social signal processing, computational neurosciences, developmental psychology, and child psychiatry. Synchrony is a complex phenomenon requiring the perception and understanding of social and communicative signals and continuous adaptation. The implementation of interactive algorithms for complex tasks in human-machine interfaces requires a better understanding of human interaction regulation strategies, especially synchrony BIB001 . Rapport building, the smoothness of a social encounter, and cooperation efficiency are closely linked to the ability to synchronize with a partner. The close link between synchrony and interaction quality bears promising perspectives for researchers building social interfaces, robots, or Embodied Conversational Agents  , [3] ,  . In addition, a lack of automatic tools for studying synchrony has limited the exploration of psychiatric conditions that affect social abilities, whether permanently (e.g., autism) or temporarily (e.g., major depression), in terms of interactive abilities. The study of interaction and intersubjectivity in infants is crucial, but currently no commonly accepted method exists for detecting and assessing synchrony and dyssynchrony between interactive partners during early pathological development. Recently, Meltzoff et al. described how research in developmental psychology may provide a good opportunity for enhancing computational models of such phenomena and vice versa BIB002 . In particular, the mechanisms of social learning have interested researchers in the field of developmental robotics, in which the long-term goal is building robots that, like infants, learn through observation, imitation, and synchronized exchanges.