Nature vs nurture. Introverts vs extraverts. Good vs evil. All of these false dichotomies describe cases where a continuous variable that could be imagined as a normal bell curve is instead conceptually divided into two “clean” categories, despite the fact that both factors are almost always present together. This simplification is particularly a problem when understanding the world requires how these factors interact. For instance, the effect of genes (‘nature’) shapes and constraints the effects of our experiences (‘nurture’), and our experiences can in turn influence how our genes are expressed. ‘Nature vs nurture’ is a terrible starting point for a proper understanding of development.
In my most recent paper, I review and discuss the false dichotomy between reciprocity and pseudo-reciprocity. These are two important models for the evolution of cooperation among nonkin. However, they are typically presented as alternative hypotheses. Why does natural selection favor individuals that help non-kin? Reciprocity is when help given causes reciprocal help from a partner. Pseudo-reciprocity is when help enables byproduct returns from the partner’s existence. In many real-world cases, helping increases both reciprocal help and byproduct returns. When you help a friend survive, you simultaneously increase their willingness to reciprocate, their ability to reciprocate (because they are alive), and any other byproduct benefits of their existence (e.g. they help you notice if there is a predator). The relative importance of these factors are hard to tease apart and they can also interact. When two individuals have aligned interests that “interdependence” can “pave the road” to forming a reciprocal helping relationship, and partners who reciprocate help will also tend to become interdependent. Reciprocity and pseudo-reciprocity are both models of how cooperation can emerge from just one factor in isolation. But in the real world, both factors are often involved and can be co-present alongside other factors like kin selection. Behavioral ecologists should stop assuming that the existence of fitness interdependence or kinship means there’s not any reciprocity. In humans, this assumption would mean that our cooperative investments in family and friends are completely unconditional and non-responsive to the behavior of the recipient. Of course, we are a little bit responsive– partially conditional. And long-term relationships are also partially interdependent. Behavioral ecologists studying social relationships should also stop equating reciprocity with complete contingency between partners being in complete conflict. Those assumptions are based on the model of tit-for-tat in the Prisoner’s Dilemma, but that model represents extreme conditions (contingency, maximal conflict, zero fitness interdependence, zero trust). The point of that model is to identify how and why reciprocity drives cooperation under cases where cooperation is most difficult, not to represent how it exists in the real world, where things are much messier.
Carter Lab 