Reciprocal cooperation in Norway rats
If only those behaviours evolve that increase the actor’s own survival and reproductive success, then it might come as a surprise that cooperative behaviours, i.e. providing benefits to others, are a widespread phenomenon.
Many animals cooperate even with unrelated individuals in various contexts, like providing food or allogrooming. One possibility to explain the evolution of such apparently altruistic behaviour is reciprocity. In reciprocal cooperative interactions, individuals help those partners that have been previously cooperative and therefore exchange favours repeatedly. Reciprocal cooperation is a ubiquitous and important human trait that we use daily.
Still, the evolutionary origin of this behaviour is largely unclear, mainly because it is believed to be too cognitively demanding for other animals. Consequently, reciprocity is suggested to have evolved in the human linage only. In contrast to this, I propose that reciprocity is not necessarily cognitively demanding and likely to be widespread. In my talk, I will shed light on the mechanisms of reciprocal cooperation in Norway rats (Rattus norvegicus).
In a series of studies, my colleagues and I have demonstrated that Norway rats reciprocally exchange goods and services between and within different commodities and independent of kinship. They most likely form attitudes towards social partners that are based on the cooperation level of the last encounter, which they remember over long time spans. Making helping decisions based on attitudes appears cognitively less complex than calculating values of received and given favours. Thus, reciprocal cooperation based on this cognitive mechanism might be in fact more widespread in other non-human animals than commonly believed.