Altruism in Animals - Implications in Evolutionary Theory

Implications in Evolutionary Theory

Researchers on alleged altruist behaviours among animals have been ideologically opposed to the social Darwinist concept of the "survival of the fittest", under the name of "survival of the nicest" — the latter being globally compatible, however, with the theory of evolution by natural selection. Insistence on such cooperative behaviours between animals was first exposed by the Russian zoologist and anarchist Peter Kropotkin in his 1902 book, Mutual Aid: A Factor of Evolution.

Recent developments in game theory have provided some explanations for apparent altruism, as have traditional evolutionary analyses. Among the proposed mechanisms are:

• Behavioural manipulation (for example, by certain parasites that can alter the behavior of the host)
• Bounded rationality (for example, Herbert A. Simon)
• Kin selection including eusociality (see also "The Selfish Gene")
• Memes (by influencing behavior to favor their own spread; see religion as a meme)
• Reciprocal altruism, mutual aid
• Sexual selection, in particular, the Handicap principle
• Reciprocity
  • Indirect reciprocity (for example, reputation)
  • Strong reciprocity
• Pseudo-reciprocity

The study of altruism was the initial impetus behind George R. Price's development of the Price equation which is a mathematical equation used to study genetic evolution. An interesting example of altruism is found in the cellular slime moulds, such as Dictyostelium mucoroides. These protists live as individual amoebae until starved, at which point they aggregate and form a multicellular fruiting body in which some cells sacrifice themselves to promote the survival of other cells in the fruiting body. Social behavior and altruism share many similarities to the interactions between the many parts (cells, genes) of an organism, but are distinguished by the ability of each individual to reproduce indefinitely without an absolute requirement for its neighbors.

Jorge Moll and Jordan Grafman, neuroscientists at the National Institutes of Health and LABS-D'Or Hospital Network (J.M.) provided the first evidence for the neural bases of altruistic giving in normal healthy volunteers, using functional magnetic resonance imaging. In their research, published in the Proceedings of the National Academy of Sciences USA in October, 2006, they showed that both pure monetary rewards and charitable donations activated the mesolimbic reward pathway, a primitive part of the brain that usually lights up in response to food and sex. However, when volunteers generously placed their interests of others before their own by making charitable donations, another brain circuit was selectively activated: the subgenual cortex/septal region. These structures are intimately related to social attachment and bonding in other species. Altruism, the experiment suggested, was not a superior moral faculty that suppresses basic selfish urges but rather was basic to the brain, hard-wired and pleasurable.

A new study by Samuel Bowles at the Santa Fe Institute in New Mexico, US, is seen by some as breathing new life into the model of group selection for altruism, known as "Survival of the nicest". Bowles conducted a genetic analysis of contemporary foraging groups, including Australian aboriginals, native Siberian Inuit populations and indigenous tribal groups in Africa. It was found that hunter-gatherer bands of up to 30 individuals were considerably more closely related than was previously thought. Under these conditions, thought to be similar to those of the middle and upper Paleolithic, altruism towards other group-members would improve the overall fitness of the group.

If an individual defended the group but was killed, any genes that the individual shared with the overall group would still be passed on. Early customs such as food sharing or monogamy could have levelled out the "cost" of altruistic behaviour, in the same way that income taxes redistribute income in society. He assembled genetic, climatic, archaeological, ethnographic and experimental data to examine the cost-benefit relationship of human cooperation in ancient populations. In his model, members of a group bearing genes for altruistic behaviour pay a "tax" by limiting their reproductive opportunities to benefit from sharing food and information, thereby increasing the average fitness of the group as well as their inter-relatedness. Bands of altruistic humans would then act together to gain resources from other groups at this challenging time in history.

Altruist theories in evolutionary biology were contested by Amotz Zahavi, the inventor of the signalling theory and its correlative, the handicap principle, based mainly on his observations of the Arabian Babbler, a bird commonly known for its surprising (alleged) altruistic behaviours.

Researchers in Switzerland have developed an algorithm based on Hamilton's rule of kin selection. The algorithm shows how altruism in a swarm of entities can, over time, evolve and result in more effective swarm behaviour.