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Evolution and Cooperation

Explanations > Evolution > Evolution and Cooperation

Direct reciprocity | Indirect reciprocity | Spatial selection | Groups selection | Kin selection | So what?

Cooperation is one of the great developments in evolution. Once creatures could learn to work together, then they significantly increased their ability to survive. From hunting together to shared protection of young, there are many benefits.

Direct reciprocity

Direct reciprocity is an immediate collaborative exchange that benefits everyone, such as in hunting together where one drives the animal towards another who kills it so both can then eat.

The reciprocal arrangement is typically one-for-one. I do something for you and you do something for me. There is little in the way of negotiation and the exchange is simple.

A common direct reciprocity it 'tit for tat' (colloquial for this for that) where I copy what you do, being helpful or unhelpful. This is a reasonable strategy when you do not know the intent of other side. Before long, you learn that you will lose out if you betray me. The problem with this is that forgiveness is not included and it is easy to fall into a negative pattern.

There is immediate and obvious benefit from direct reciprocity and there is relatively little need for trust into the future. Trust is a critical question and is almost always lost at some time. Forgiveness is hence critical to allow for new opportunities in collaboration.

Indirect reciprocity

Indirect reciprocity is where there is a separation between contribution and gaining benefits from others. such as caring for the young of others who are out hunting for food.

The complexity of indirect reciprocity means that this is more appropriate where species have a greater ability to reason, which limits any sophistication in this activity to humans (although some people still do not get it).

Indirect reciprocity requires greater trust as there is more potential for one party to betray the other and get away with it. This is facilitated by reputation, which needs a language by which an individual's trustworthiness can be communicated.

Spatial selection

Spatial selection is a principle used by individuals and groups who live in protected areas where they are immune from attack by predators The basic idea of this is that if they can find a safe place, then they will be more likely to survive. The stability and security also means that they are more likely to have more children, which then grows the population faster.

In this spatial heterogeneity it is important that people do not leave the tribe. By staying and working together for the greater good, each individual has a better chance of survival. This becomes even more true when there is conflict between tribes as the larger tribes have a greater chance of winning.

A growing population will need to expand its territory. Humans have done this right across the world. By living and working in cooperative tribes, they have spread to every corner of the globe, even where insects cannot survive.

Spatial selection also happens in the social divisions within society. People with similar amounts of money and status tend to live in the same areas, become friends and intermarry.

Groups selection

Warfare is a natural result of spatial selection where individual groups or tribes start expanding and so fall into conflict with nearby tribes as they fight for land rights, from hunting to water access to outright exclusive ownership.

The principles of individual selection now apply to groups. Those who can mutate and adapt better than others can drive away, enslave or kill their competitors, taking their land in the process.

In warfare, extreme collaboration is needed, fighting alongside your colleagues and being prepared to lay down one's life for the greater good of the tribe.

The same principle applies to companies, where groups of people fight for a limited supply of customers, collaborating and working hard together for group success (and hence individual success).

Kin selection

Kin selection starts with the choice of a mate. If you have a better choice when looking for a mate, then, provided you are good at choosing, you will be more likely to find a mate who is fertile and comes with associated power, such as a successful family.

It continues with our clear support of those to whom we are related over non-relatives. We will incur cost to support our kin, who carry the same genes as us. We even give more weight to closer relatives, whose genes are more similar to ours. Kin hence tend to support one another also and there are often very strong obligations to do so (hence sayings such as 'blood is thicker than water'). Evolutionary biologist J. B. S. Haldane summed it up when he said "I will jump into the river to save two brothers or eight cousins."

Kin pass genes on to one another. Hence more successful people are more likely to have more successful children. This also applies to non-genetic factors such as having money and status to lavish on your children.

So what?

So in developing systems of cooperation, look for ways to use these factors. If people only seem to act at direct reciprocity level, seek to use evolutionary forces to move them to a higher level.

See also

Natural Selection, Rules of Evolution, Trust

Axelrod, R. (2006). The Evolution of Cooperation. Basic Books

Nowak, M.A., Tarnita, C.E. and Antal, T. (2010). Evolutionary dynamics in structured populations, Philosophical Transactions of the Royal Society B, 365, 19–30