Research
Our research explores the proximate mechanisms, cognitive and motivational, underlying the cooperative behaviour of human and non-human great apes. We employ an interdisciplinary approach drawing methodologies and knowledge from psychology, anthropology, behavioural economics and evolutionary biology.
Teamwork
Coordination and Communication in Chimpanzees
Part of our research addresses to which extent chimpanzees are capable of intentional collaboration, employing different strategies to facilitate coordination with a partner when working together towards a common goal. In previous studies we found that chimpanzees recruit a partner when the problem requires collaboration and that they preferentially recruit skillful partners. They are also capable of coordinating and “negotiating” which tray to choose, when there are two collaborative pulling trays with different amounts of rewards, and initial disagreement between the two individuals over which one to choose.
We have also found that they help a partner by transferring the tool she needs to perform her role in the task. This line of studies suggests that they understand the role that the partner plays in the collaborative task and that they are able to employ a variety of strategies to initiate and sustain the collaborative activity with her/him.
In a more recent study, we found that they are also capable of developing a simple but effective communicative strategy to direct the partner to the location of tools that they both need to work together.
We are now exploring the flexibility of this communicative strategy in a project funded by the Templeton World Charity Foundation.
Sharing the Spoils in Chimpanzees and Children
How individuals share the resources obtained after collaborative effort is important for the long-term stability of collaboration. In our research we have found that whereas chimpanzees do not reward partners depending on their contribution to the collaborative task (e.g. John et al. 2019), young children from around 3 years of age share resources more equally after joint than individual work (e.g. Melis et al. 2013).
Prosociality
Humans are uniquely prosocial and often willing to altruistically help others, even strangers and individuals who will they never encounter again, for example, by sharing valuable resources and by helping others achieve their goals. Often (but not always) this behaviour is motivated by a genuine concern for the welfare of others, but is this trait uniquely human?
We have found that chimpanzees possess basic skills and motivations to engage in low-cost helping behavior. In situations, in which selfish benefits can be ruled out, chimpanzees provide instrumental help to others struggling to obtain an out-of-reach material goal. However, one important factor that limits chimpanzees’ helping behavior is that recipients need to provide clear cues (or signals) about their goals and/or needs (e.g. Warneken et al. 2007, Melis et al. 2008, Melis et al. 2011, Melis et al. 2018)
Reciprocity
Humans possess a wide range of strategies to control cheating which allow high levels of cooperation to evolve and stabilize among unrelated individuals and in large groups. One mechanism that supports the long-term stability of prosocial behaviour is direct reciprocity. In direct reciprocity individuals exchange favours in repeated encounters, paying a cost short-term but benefiting long-term.
From a proximate perspective there are various ways in which such reciprocal interactions can emerge. For example, individuals may engage in past-driven reciprocity, keeping track of past interactions with others and preferentially helping and sharing with individuals who were helpful towards them before. It is possible that the reciprocal cooperation observed in chimpanzees relies in such a past-oriented mechanism (e.g. Melis et al. 2008).
A cognitively more complex form of reciprocity is future-oriented or strategic reciprocity. In strategic reciprocity individuals invest in others in anticipation of future payback or motivated by the possibility of future selfish benefits. Our research has shown that humans from age 5 on, understand the long-term benefits of exchanging favours, which helps expanding the range of situations in which individuals act prosocially (Melis et al. 2016).
CoRe- The Cognitive Foundations of Human Reciprocity
In our CoRe project funded by ESRC-NSF, and in collaboration with Elliot Ludvig (Psychology, University of Warwick), Felix Warneken and Sebastian Grueneisen (Psychology, University of Michigan) we are now exploring the cognitive mechanisms supporting such strategic positive reciprocity. In particular, we are investigating the role that three cognitive traits have in strategic reciprocal cooperation: planning, patience, and risk tolerance. We are integrating three lines of research, encompassing the evolutionary basis of human reciprocity through species comparisons with our closest evolutionary relatives, the relationship between these cognitive skills and the emergence of reciprocity in human development, and individual differences and its relationship to the cognitive skills in adults.
Individuals from all three populations (chimpanzees, children of different ages, and human adults) will participate in five different tasks. Three of the tasks will measure their planning skills, patience, and risk tolerance, whereas the fourth and fifth tasks will measure tendency to invest in partners who can reciprocate in a subsequent interaction.
The UK-based team is focusing on the work with chimpanzees and human adults, whereas the Michigan-based team is focusing on the work with human children.
Dishonesty
Fairness considerations and inequity aversion arise from a young age and in different cultures. In fact, the ability to evaluate relative payoffs and negative reactions to inequity may be crucial in an ultra-cooperative species like humans for discriminating beneficial partners for future interactions. One way to deal with and remedy such unfair situations may be by behaving dishonestly. In this project, and in collaboration with Elliot Ludvig (Psychology, The University of Warwick) and Nick Chater (Warwick Business School) we are looking at the link between (un-)fairness perceptions and dishonest behaviour.