27 Mar 2009

Evolutionary theory and rehabilitation

2009 is the 200th anniversary of the birth of Darwin 

2009 is the 200th anniversary of Darwin's birth and the 150th anniversary of his seminal book ‘Origin of Species'. The theory of evolution is one of the most important biological discoveries, period. However, evolution has also been mis-used to promote thoroughly bad ideas such as eugenics and social engineering. In the area of disability, the theory of evolution is tainted with these notions and terms such as ‘survival of fittest' and ‘natural selection' are quite offensive and gives the theory of evolution a bad name (which I think it might not deserve).

There are two threads of thinking that I want to very briefly explore to show that the theory of evolution need not be seen as the ‘enemy', and may actually be helpful in understanding human behaviour.

A special issue of the Lancet in December 2009 explored the legacy of Darwin's theory of evolution and a very interesting essay was written by Hansen, Janz and Sobsey from Canada. In this paper, they are critical of the common understanding of the word ‘natural' in ‘natural selection', as if impairments and disability are not seen as just natural variations of human biology but as biology "gone wrong".

These authors argue that despite common understanding of eugenics as an application of Darwinism, in fact it is an application of an illegitimate form of darwinsim. It is not Darwinist at all. The reason for this argument lies in the meaning of ‘natural' in ‘natural selection'. Eugenics requires that natural selection be replaced by intentional human control, that is artificially - note, not natural - manipulated according to somebody's concept of what constitutes fitness.

There is now the disturbing development of what these authors rather provocatively call the "new eugenics" repackaged into a more palatable form called genetic counselling.  There is a very difficult debate, which itself may be insulting to people with disabilities. And so I don't really want to go down that track now (although it could be an important topic to discuss another time). Rather, I wanted to simply highlight the idea that ‘natural selection' itself does not exclude people with illness or disability and that eugenics is actually not darwinist at all but a process of unnatural selection.

The second thread that I wanted to explore, is how the theory of evolution could actually help explain why we should care for each other, including for people with disabilities. This has been called the ‘survival of the nicest' in a Guardian column by Diab. For those who don't read geeky popular science books, the ‘selfish gene' was a slightly misused notion popularised by Richard Dawkins to illustrate the one-way drive to replicate that ensures the ongoing presence of genes within our genome.

There are many strands of evidence to suggest that there might be ‘selfless' genes - genes that guide us to behave in ways that appear to disadvantage us as individuals but help ensure the survival of the community in which we live. One example is microbial biofilms which are colonies of bacteria living on a commonwealth of slime that they secrete. Cheaters who live off the slime but do not secrete any (it is costly for the bacteria to do this) put the entire group at risk.

Daniel Dennett wrote a book about this and other ideas called "Freedom Evolves" which showed how morality and cooperation can be explained from evolutionary principles. Another example comes from games theory. I know that this is getting more geeky but I found it interesting. An example of game theory is to imagine you are one of 2 people accused of a crime. If you cooperate and both plead guilty you both go to jail for 3 years, if you snitch pleading not guilty and the other person does plead guilty then you go to jail for 5 years and he gets only 1 year. If you both plead not guilty then you both go to jail for only 2 years. What should you do? In computer simulations, it turns out that the best policy in the long run is to cooperate and not snitch. So, sometimes you will be penalised by pleading guilty but overall, if everyone in your community had to play this game, cooperation wins. Survival of the nicest.

Another example is symbolic language. Gärdenfors (a professor of cognitive science) from Sweden has written an interesting paper showing that one evolutionary advantage that humans get from symbolic language is to cooperate about future goals. As rehabilitationists know, goals come into everything. In many ways, humans could be defined by their unique ability to plan for future goals. In his paper, Gärdenfors argues that only language makes it possible to cooperate about future goals.

If this is so, then cooperation must also be critical for evolutionary advantage. One very important idea that Dennett raised was that for others to trust that you are a cooperator rather than a cheater, you have to have already demonstrated this. Wearing a T-shirt that says "Trust me - I am a cooperator" doesn't work. Consistently being a nice person is more effective than being nice only when you feel like it. There may be many other reasons to be nice to people, but survival of the species might be the most important one. I would therefore like to commend us all for working in caring professions and to remind us that doing our best for our patients and clients not only helps those clients but also the human race.

Dawkins, R. (1976). The Selfish Gene: Oxford University Press.

Dennett, D. C. (2003). Freedom Evolves: Viking Books.

Diab, K. (2009). Survival of the nicest [Electronic Version]. guardian.co.uk. Retrieved 26/3/2009 from http://www.guardian.co.uk/commentisfree/2009/mar/10/evolution-genetics.

Hansen, N. E., Janz, H. L., & Sobsey, D. J. (2008). 21st century eugenics? The Lancet, 372(Supplement 1), S104-S107.

Gãrdenfors, P. (2004). Cooperation and the evolution of symbolic communication. In K. Oller & U. Griebel (Eds.), The Evolution of Communication Systems (pp. 237-256): MIT Press.

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