The theory of reciprocity, or reciprocal altruism, is a controversial topic when examining animal behavior. Reciprocity does not seem to fit into the theory of natural selection. The thought that reciprocity can evolve is further scrutinized when individuals in the species are observed to go against their reciprocal “debt.” Some scientists believe reciprocity could simply be categorized under other sectors of altruism such as kin selection, mutualism, or postponed cooperation. The variety of generalized speculations to the underlying cause of this type of altruistic behavior has caused mass debate among biologists. In order to understand the contention reciprocity generates between scientists a definition of this term must first be constructed.
The simple definition of reciprocal altruism is developed by observing a series of events between two individuals. An individual who performs a beneficial act, the helper, for another, the receiver, is usually found to be later repaid by the receiver of the assistance (Alcock, 2013). The key factor that differentiates reciprocity from kin selection is that the two individuals are unrelated. Reciprocity persents itself in a variety of species including primates, pied flycatchers, and bats. Though there have been studies to support the theory of reciprocity, it can be difficult to determine if a case of reciprocity is pure altruistism, or instead a function of mutalism or postponed cooperation.
In a reciprocal relationship, the fitness of the individual who provided the help generally is not decreased in the long term. The initial fitness cost is later returned by the receiver. This returned fitness cost supplies evidence for the argument that reciporcity could simply be division of mutalism or postponed cooperation. However, “defectors”, or receivers who do not return a benefitial act, ruin this method for arguement. If the intital fitness cost to the helper is not returned by the receiver that helpers fitness will be reduced. This circumstance seems to cancel out the mutalism and postpone coppoeration theory. These “defectors” in the species also provide reason to why reciprocity is less likely to evolve. So, why has reciprocity evolved?
Though reciprocity and its direct payback behavior has evolved it is still a rare phenomenon in the animal kingdom. In theory, genes which code for the reciprocal behavior are passed to future generations unless they are selected against. Genetics are not the only element of this developing behavior. Environmental factors are always intertwined when it comes to the development of behavior. This behavior has simply not been selected against.
Upon examination of the different aspects of reciprocity we can begin to understand why there is such controversy in the biological field when classifing this theory.
Alcock, J. (2013). Animal behavior: An evolutionary approach. Sunderland, Mass: Sinauer Associates.