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
Cooperation forms the basis of our society and becomes increasingly essential during times of globalization. However, despite technological developments people still prefer to meet face-to-face,... Show moreCooperation forms the basis of our society and becomes increasingly essential during times of globalization. However, despite technological developments people still prefer to meet face-to-face, which has been shown to foster cooperation. However, what is still unclear is how this beneficial effect depends on what people know about their interaction partner. To examine this question, 58 dyads played an iterated Prisoner’s Dilemma game, sometimes facing each other, sometimes without face contact. Additionally, explicit feedback regarding their decisions was manipulated between dyads. The results revealed that participants were more cooperative when they saw each other compared to when they could not, and when receiving reliable compared to unreliable or no feedback. Contradicting our hypothesis that participants would rely more on nonverbal communication in the absence of explicit information, we observed that the two sources of information operated independently on cooperative behavior. Interestingly, although individuals mostly relied on explicit information if available, participants still cooperated more after their partner defected with face-to-face contact compared to no face-to-face contact. The results of our study have implications for real-life interactions, suggesting that face-to-face contact has beneficial effects on prosocial behavior even if people cannot verify whether their selfless acts are being reciprocated. Show less
The central theme of this dissertation is the (un)willingness to reward cooperation and punish non-cooperation. Whereas rewards and punishments can be effective means to enhance cooperation in... Show moreThe central theme of this dissertation is the (un)willingness to reward cooperation and punish non-cooperation. Whereas rewards and punishments can be effective means to enhance cooperation in social dilemmas, a prerequisite for any effect of sanctions is that people are willing to administer them. In the present work, I shed more light on this important – yet long neglected – topic. The aim is twofold: (1) identifying determinants of the use of sanctions in social dilemmas, and (2) testing the central proposition that people are not as willing to punish non-cooperative choice behavior as they are willing to reward cooperative choice behavior. The results of this dissertation show that the type of sanction people have at their disposal (Reward versus Punishment), the type of social dilemma people face (Public good dilemma versus Common resource dilemma), the extent of personal responsibility people have for the sanction (Individual responsibility versus Joint responsibility), and the timing of the sanctioning decision (Beforehand versus Afterwards) are important determinants of the (un)willingness to sanction in social dilemmas. These findings reveal that there are not only psychological processes at play that foster sanctioning, but also psychological processes that hamper sanctioning. Show less
The making of commitments is often used as an intervention aimed at increasing pro-environmental behavior. Research shows that when people commit to changing their environmental behaviors, they... Show moreThe making of commitments is often used as an intervention aimed at increasing pro-environmental behavior. Research shows that when people commit to changing their environmental behaviors, they tend to adhere to their commitments. In this dissertation it is investigated whether commitment making is effective in improving agricultural nature conservation and with that, environmental quality of farm lands. Furthermore, a conceptual review is offered, as well as an experimental investigation of the conditions under which people are willing to make such commitments. Results show that commitment making combined with tailored information is indeed effective in improving farmers’ nature conservation. Several explanations of the effect of commitment making on behavior are offered. Also, it is shown that that the willingness to invest in commitment making is contingent on the interplay of dispositional trust and situational expectations. Taken together, this dissertation aims to provide the reader with a perspective on the entire process of commitment making: under which conditions people engage in it, if it is successful in altering behavior, and how it is successful. Show less
This dissertation focuses on social dilemmas, and more specifically, on environmental uncertainty in these dilemmas. Real-life social dilemma situations are often characterized by uncertainty. For... Show moreThis dissertation focuses on social dilemmas, and more specifically, on environmental uncertainty in these dilemmas. Real-life social dilemma situations are often characterized by uncertainty. For example, fishermen mostly do not know the exact size of the fish population (i.e., resource size uncertainty). Several researchers have therefore asked themselves the question as to how such uncertainty influences people’s choice behavior. These researchers have repeatedly concluded that uncertainty is detrimental to the collective because it induces over-harvesting. The present dissertation aims to provide a more comprehensive view on uncertainty in social dilemmas. Whereas earlier research has primarily investigated how uncertainty influences harvesting decisions, this dissertation also focuses on how environmental uncertainty affects interpersonal processes. This dissertation introduces a perspective that argues that environmental uncertainty hampers the application of the equal division rule, which in turn influences how group members interact with one another. In six chapters, I elaborate on numerous implications of this notion. By focusing on three key aspects of interpersonal processes (i.e., tacit coordination, justification pressures and interpersonal emotions), and by testing my ideas in seven empirical studies, I demonstrate that the effects of uncertainty are much more differentiated than is portrayed in earlier research. Show less
