Facial expressions play a fundamental role in social interactions, as demonstrated by our spontaneous inclination to mimic emotional expressions of others. In this thesis, I take a broad... Show moreFacial expressions play a fundamental role in social interactions, as demonstrated by our spontaneous inclination to mimic emotional expressions of others. In this thesis, I take a broad perspective and show that people mimic each other on many more levels than previously thought. Special attention is given to autonomic mimicry (synchrony in heart rate, skin conductance and pupil diameter), which is an underexplored area of research. In the first empirical chapter, I show that pupil mimicry activates social brain regions and when the pupils of interacting partners synchronously dilate, trust is promoted. In the subsequent real-life experiment, I demonstrate that synchrony in heart rate and skin conductance boost attraction between people on a date. In the remaining chapters, I manipulate mimicry with optical illusion and brain stimulation to provide evidence that autonomic and facial mimicry are controlled by distinct neurological pathways. Together, these findings implicate that the tendency to automatically mimic and physiologically align with others can result in emotional contagion – the tendency to ‘catch’ another person’s emotion, which in return encourages trust and affiliation. In sum, this research takes a fundamental step towards the understanding of the neurobehavioral pathways through which mimicry influence (pro)social behaviors. Show less
Human cooperation is an astonishing phenomenon, as only humans exhibit such immense scale, complexity, and frequency in working together with other people. In this dissertation, I investigate how... Show moreHuman cooperation is an astonishing phenomenon, as only humans exhibit such immense scale, complexity, and frequency in working together with other people. In this dissertation, I investigate how nonverbal communication between two individuals affects cooperative success as well as methodological challenges when examining this topic in laboratory settings. To answer these questions, the dissertation comprises four chapters presenting two theoretical and two methodological studies. In the first two chapters, I demonstrate the beneficial effect of face-to-face interactions on cooperation. I subsequently show that physiological synchrony emerges during social interactions and is positively associated with cooperative success. This finding suggests that physiological synchrony might be an underlying mechanism for the beneficial effect of face contact on cooperation. In the methodological studies, I place the tasks typically used to measure cooperation into the broader context of prosocial behavior. Furthermore, I address the statistical challenges inherent to measuring synchrony between interaction partners. The cardinal point of this dissertation is that interpersonal processes that we are not aware of play a fundamental role in how we behave towards other people. Addressing methodological challenges that come along with studying dyadic interactions will greatly advance our understanding of social phenomena that make us human so unique. Show less
