Response to the blog: http://iloveprimates.com/2011/
Researchers continue to try to understand
Reciprocal altruism/reciprocal altruism in nature. Altruism in nature is typically defined as an unselfish act that benefits another (non-kin). This concept, as it manifests itself nature seems very strange, based on the foundations of Darwinian evolution—that any trait to share or benefit another (non-kin) at one's expense is not likely to survive multiple generations. However, reciprocal altruism can be more complicated because some benefit may come back to the initiating participant, with ultimate advantages for both participants. In this blog, I will respond to a blog post that explores the question of reciprocal altruism in primates (see link above).
The blog post does a nice job of introducing the concept of reciprocal altruism. Indeed, the Trivers work, The Evolution of Reciprocal Altruism, suggests that the participants must have the ability to remember one another (primates have exceptional longer-term memory) and the cost of giving (time spent grooming, food shared, etc) must be outweighed by the reciprocated benefit (coalition support, food sharing, etc). The blog post provides two specific examples from vervet monkeys and male chimpanzees, and includes a short video of this type of behavior (The Video).
Interestingly, reciprocal altruism has been explored across many species including various insects, bees, birds, etc. Despite the high-level overview from iloveprimates.com, there are some additional research perspectives and context that help to frame the discussion. One such insight is that the reciprocal altruism tends to occur between "high-ranking" individuals. This is important because it means that this relationship dynamic is even less "altruistic" if primates lower down the pecking order do not have access to such opportunities. Additionally, evidence has shown that the level of reciprocity is quite equal (think banana for banana), but there can be variation for reciprocating up the ladder to a "high ranking" individual. Finally, data analysis has revealed the complexity and range of these altruistic acts, from grooming, food-sharing, and fighting coalitions. This evidence is important because it means that higher forms of altruism existed prior to the development human-like cognitive abilities. So, keep how far humans have evolved in context the next time you lend someone your metrocard or donate money to a cause!