Kinematic Characterization of Spontaneous and Posed Emotional Facial Expressions

Emotion is one of the building blocks of human life. However, how humans dynamically and genuinely express their emotions is still little studied. Considerable work in the past decade has criticized the classical investigative methods, invoking for a more sophisticated approach to analyse how humans dynamically manifest facial expressions. Another major drawback of available literature is that studies typically using static images of posed expressions. However, small changes in the dynamical development of a facial display may allow to characterize and distinguish genuine from posed facial expressions, a topic poorly investigated. Even when dynamic stimuli were used, the adopted induction method was heterogeneous. To conclude, the lack of objective tools to investigate the dynamic characteristics of expression and the incongruencies in the adopted stimuli and induction methods are all sources of poor consensus on the syntax and morphometry of facial expressions of emotion. It is time to overhaul the science of emotion with tools such as 3-D kinematics in conjunction with Facial Action Coding System (FACS) coding, and valid experimental designs such as more effective induction methods and continuous self-ratings. In my thesis, I manipulated the type of expressions (posed vs. spontaneous) and the method of induction (Emotional vs. Motor Contagion). In a first set of experiments (see Part 2, Experiment 1 for each chapter), I presented two different stimuli: i) videoclips extracted from films - aimed at eliciting spontaneous expressions of basic emotions (i.e., Emotional Contagion), and ii) static 2-D pictures of expression selected to perform posed expressions (Voluntary Mimicry). In a second set of experiments (Experiment 2 for each chapter) spontaneous expressions were elicited by videos showing people expressing their emotion in a direct, frontal manner (i.e., Motor Contagion). The results showed that spontaneous and posed expressions for the same basic emotions are in fact characterised and distinguished by a series of spatial, speed and temporal parameters of movement (Part 2). Moreover, felt emotions are not unique, prototypical and mutually exclusive, but are composed by different nuances of different emotions, as revealed by my new paradigm (CER) paradigm, that permits to highlight the relative contributions of each emotion (Part 3). In my doctoral dissertation, I have identified entirely new methods for studying emotional expressions, which will eventually bring about a theoretical and methodological change in the study of emotions. I believe that the most useful solution to address the complex world of emotion expression is to define a new approach that integrates traditional and innovative methods and new tools for self-detection of multifaceted emotional experience.