Below we describe the research programs of the ACL:

How do people mentally represent their interdependence with others? Any interaction can be characterized by a specific form of interdependence, but most often the actors in those situations do not have direct, objective knowledge of the type of interdependence that characterizes the interaction. This program of research  includes (a) developing a theory about the function and structure of interdependent inferences (Functional Interdependence Theory; FIT), (b) testing the structure of interdependence inferences, (c) testing cues people use to infer specific properties of interdependence, and (d) understanding the role of interdependence inferences in decisions to cooperate. In the process of our empirical work, we have also developed a multidimensional scale that measures how people think about of their interdependence (the Situational Interdependence Scale; SIS).

Interdependence, Cooperation, and the Punishment of Social Norms in Daily Life. Much research on human cooperation studies cooperative behavior in the laboratory using abstract, social decision making tasks. While this method has obvious advantages of experimental control and internal validity, an over reliance on these methods has resulted in a lack of descriptive research documenting when and how people cooperate in daily life. The ACL has been using experience sampling methods to study the patterns of interdependence people experience in daily life, and when and how they cooperate with others in those situations (Columbus, Molho, Righetti, & Balliet, 2021). Further, we have used these methods to study prominent strategies to impose costs on noncooperators, such as gossip, direct confrontation, and ostracism (Molho, Tybur, Van Lange, & Balliet, 2020; Cruz et al., 2021). Also, cross-societal research has uncovered that indirect responses to norm-violations, such as gossip, are quite typical of western, rich societies (Eriksson et al., 2021).  ACL collaborates with the center for Global Social Norms led by Kimmo Eriksson.

Ecological Origins of Cross-Societal Variation in Cooperation (ERC-Consolidator Grant). A puzzle facing the social sciences is understanding the origin of cross-societal variation in cooperation. Strikingly, multiple disciplines propose the same, not yet established, explanation: ecological conditions, such as subsistence, environmental hazards, and relational mobility, determine how people are interdependent (i.e. how actions affect own and others’ outcomes), and interdependence can be the mechanism through which diverse ecologies shape a culture of cooperation. For example, rice versus wheat production plausibly has led to more versus less dependence on others, which then led to different cultures (e.g. values, beliefs, and norms) that affect strategies of when and how people cooperate. We use a multi-discipline, multi-method approach to answer three questions about whether ecologies indeed create different interdependence, and how this leads to variation in culture and cooperation: 1) Do ecologies create different kinds of interdependence? 2) Can interdependence cause differences in culture and cooperation? and 3) Does variation in interdependence relate to culture and cooperation?

The ACL is also collaborating with the Human Generosity Project, to study how interdependence, contributions to public goods, reciprocity, and preferred strategies for maintaining cooperation vary across small-scale societies.

Climate Change. By its focus on the conflict between short-term self-interest and longer-term collective interest, social dilemmas provides a suitable model for one of the most important societal challenges:  climate change.  In our program of research, we focus on various questions, such as how we can make climate change less abstract by reducing psychological distance (Van Lange & Huckelba, 2020) and by highlighting consequences for our (grand)children (Van Lange, Joireman, & Milinski, 2018). We have also studied whether variables that are inherently dyadic, such as social value orientation and social mindfulness, predict concern and actions aimed at mitigating climate change (Kirkland et al., 2022; Van Doesum et al., 2021).  And finally, we study the influence of making the ecological costs of climate change more concrete, such as the elimination of insects or trees (Bastian et al., 2019).

Indirect Reciprocity and Reputation Management. Humans are conditional cooperators who selectively cooperate in situations that can result in direct and indirect benefits. One problem for conditional cooperators is understanding when current cooperation can result in indirect benefits. Our lab has been testing hypotheses about how people manage their reputation in a social network to acquire indirect benefits. We are specifically interested in how properties of social networks (now and in the ancestral past) can be used to generate testable hypotheses about adaptations humans have to identify opportunities to cooperate and acquire (often unforeseen) indirect benefits in a social network (see Wu et al.)

Cooperation Databank (CoDa). We developed the Cooperation Databank (CoDa) – a databank that contains ~2,600 studies on human cooperation (1958-2017) published in Chinese, English, and Japanese. Experts annotated each study for 275 variables related to cooperation, including the quantitative results (e.g., effect sizes). We designed an ontology that defines and relates concepts in cooperation research and that can represent the relationships between individual study results. We have created a search engine that, based on the dataset, enables users to retrieve studies that test the relation of variables with cooperation, visualize these study results, and perform (1) meta-analyses, (2) meta-regressions, (3) estimates of publication bias, and (4) statistical power analyses for future studies. CoDa is part of an ERC Starting Grant awarded to Daniel Balliet (additional information).

Hybrid Intelligence. Daniel Balliet and the ACL are part of a consortium of computer and social scientists who have recently been awarded the Gravity Grant by NWO (20 million euros for 10 years, 2020 – 2030). You can learn more about the project at the Hybrid Intelligence Center. One of our first projects will involve working with Hayley Hung at TU Delft to study the cues people use to select cooperation partners. We aim to use this information to design A.I. that can assist people in selecting cooperation partners.