Recollections and Reciprocity - The Interplay of Memory and Cooperation

Evolution predicts the survival of the most competitive members of a group. If only those behaviours evolve that increase the actor's own competitiveness, then it might come as a surprise that cooperative behaviours, i.e., providing benefits to others, are a widespread phenomenon. Various animals, including humans, frequently help their conspecifics by providing care, food, information, or support. One possibility to explain these behaviours is reciprocity, i.e., "I scratch your back, if you scratch mine". By helping those that were helpful before, cooperative individuals are better off than individuals that never help, but also never receive any help.
Humans reciprocate help in daily interactions and even global trading contracts are based on the principle of reciprocation. Other animals have been shown to exchange favours reciprocally, too. However, it is not clear how (especially small-brained) animals can achieve this seemingly cognitively demanding form of cooperation, as a lot of information often stemming from several partners needs to be memorised over potentially long timeframes. This high memory capacity load has been suggested to be the main factor limiting reciprocity in non-human species.
Norway rats are ideal study animals to deepen our understanding of the cognitive processes of such reciprocal cooperation. Rats are highly social animals that can be easily trained in captivity. Importantly, they are well known reciprocators that help preferably cooperative partners, which helped them in the past, using various tasks. Hence, they are ideal to conduct non-invasive experimental tasks to causally understand cooperative decisions.
This project aims at shedding light on the interplay between memory and reciprocity. Specifically, we will first study what kind of details rats remember about their interaction with a partner in order to reciprocate. In the next steps we will make it more and less difficult for the rats to memorise their partner's latest helpful action to investigate whether memory demands are flexible in reciprocal settings. To do so, we will keep a colony of rats in our well-equipped rodent facility and train individual rats to participate in cooperation experiments, in which rats can donate food to each other and groom each other.
Thus, this project will not only improve our understanding and appreciation of the complex social life of rats, but it will also shed light on the evolutionary and psychological origins of (human) cooperation by investigating potentially shared mechanisms of stable cooperation. In so doing, this work brings us face to face with how cooperative we are in comparison to other species and how closely our behaviour is connected to that of other animals.