Friday, August 7, 2009

Meme--Gene Coevolution

Human evolution is a product of not one, but two replicators – the gene and the meme.

This post is about the effects of taking a new replicator into account regarding human evolution. Coevolution is a significantly more complex model, as opposed to evolution by genetic pressures alone. Memes interact with genes, and it is important to note that the rate of evolution amongst ideas, in the present, is greater than that of genetic evolution. Susan Blackmore suggests that this increased capacity for meme evolution is actually driving genetic evolution, in what she calls, “memetic drive.”

The following is an explanation of how cultural ideas drove the evolutionary process that created the disproportionately large brains in humans; there were three critical stages that led to this: (1) individuals that imitate and learn from other individuals, not just the environment are better at surviving, (2) the generalist imitators that have enhanced selection of memes are favoured because they can tell useful memes from harmful ones, and (3) preferential mating results in more offspring that have a genetic predisposition towards meme selection and capacity functions, favouring the expansion of the brain (if we assume that a bigger brain is better at holding and selecting memes). This argument, suggesting that memes actually play a large role in genetic pressures, may be generalized to say that any meme that acts as a signal of status, within society, causes sexual selection, and therefore has an influence on genetic pressure. The genes that are better for a particular meme exerting the force will appeal more to selection process.

Clearly, cultural units of replication can guide genetic evolution towards a shared goal – but what if they pursue opposed goals? Meme evolution has been accelerating because faster rates of evolution were selected as beneficial. Is there a struggle between memes and genes? The increased rate of memetic evolution, as I have said before, has the potential to be detrimental to the selfish genes. Genes originally adapted to allow the spread of ideas simply for the symbiotic relationship. And the genes had to keep a leash on memes by increasing the selective process involved in accepting or rejecting ideas. With this in mind, I’d like to turn to the research of Larry Bull, Owen Holland, and Susan Blackmore on the coevolution of these two replicators.

They created a computer simulation to test the effects of varied rates of evolution between two selfish replicators. The results are as follows: when there was a low interdependence between genes and memes, both replicators successfully evolved. That is, when the evolution of the latter had little influence over gene evolution and vice versa, both could evolve. When there was a slightly higher interdependence, however, the rates of evolution allowed enormous benefits to one, while the other, “degraded to a random walk” (meaning that it did not continue to tend towards enhanced survival as evolution would result in). It was also shown that for genes to continue to be successful in a coevolutionary model, genes had to have higher selective forces over which memes to adopt (selecting and restricting the memes that have detrimental effects on genes). Of course, this is what you would expect as you do not want maladaptive memes overtaking humans.

Even though memes have the potential to decrease genetic fitness, a meme will not necessarily endorse a mutation that has this effect. By decreasing genetic fitness, they indirectly decrease their own fitness, because the human mind is the physical medium upon which they depend. This is not unlike a virus that doesn’t want to kill the host -- because killing it would limit its own spread. The only cases in which memes will ignore this cost, is when the benefit of its own survival outweighs that of the negative influence on genes. The key to this is that memes are still dependant on humans as a medium of transmission – for now. Hold that thought.

Greater selection by genes upon cultural traits allows greater benefits to genes. This implies that as meme evolution continues to advance, genes need to increase their selective attributes to remain in control of memes. Memes experience benefits from increasing rates of evolution, until they are about 30 times faster at evolving in comparison to genes – at which point there are no benefits or negative effects of increasing the evolution rate. This, perhaps, is because they reach the edge where going any faster would lead to decreasing meme fitness, due to the interdependence between the two replicators.

Now, what if memes were not dependent upon genes? Ex. someone gets the idea to create a literally self-propagating physical system that evolves without genes. What if you could design a system that just rapidly increases its rate of evolution, exponentially increasing in complexity? The system would necessarily have to be designed to achieve something, otherwise it would have no algorithm to base selection upon – it has to select useful ideas for whatever its goal is. Humans could make a universal application machine which begins with whatever goal you want in mind, and evolves into a system for that purpose. Just a thought.

One more quick note on clarifying the nature of a meme. They do not actually make copies of themselves, so they are not replicators in that sense. They achieve replication, in that they are transmitted and copied whenever they are observed, as they leave an impression in the mind. This is what allows the inheritance factor of evolution to come into play. And a meme doesn’t always jump from brain to brain either – it may be a meme that affects the expression of other memes or itself though.

To recapitulate – memes and genes, which are in control? Both, as they both have a degree of dependence upon each other (currently). Meme-gene coevolution really is an interesting phenomenon.

1 comment:

  1. "Humans could make a universal application machine which begins with whatever goal you want in mind, and evolves into a system for that purpose. Just a thought."

    Utterly agree. It is called History, what Hegel called mankinds becoming aware of itself. I propose that since man learned to manipulate memes to gain power, the hierarchy can then monopolise memetic production. By doing so, they homogenise a group in their image, with the 'imagined community' consisting of the 'official narrative', created by those in power, for those in power.

    First it was religion, then state, then commodity (pierre Levy) that came to dominate and saturate a culture enough to comprise the majority of identities. Those identities then continue to parrot the memes of their rulers, be it priest, lord, MP or Media moghul.

    Yet our moral sphere is corrolated with that which we know, a memetic version of Hamiltons Law which makes total evolutionary sense if you think about it. Therefore it is corrolated with communication technology. Enter propaganda, censorship and mass-misinformation when two opposing top-down derived identities grow against each other.

    But now we have a revolution qualitatively different to all those before. Each before had retained the top-down monopoly on memetic/identity creation, merely spreading the power a little here, giving the masses a little power there, yet always maintaining that power of memetic creation. Ever since capitalisms desire to create common vernaculars so that markets for printing presses would be large, they have continue to sow the seeds of their destruction. Capitalism cannot stop creating more and better communication networks, eliminating the unknown and creating moral concern of global proportions. Our minds ability to empathise regardless of space and time allows us to incorporate all of mankind into our sense of self, and then the exploitation will not stand.

    Dissonance will sweep the earth. Horizontally derived imagined communities spanning the globe, shattering the 'official narrative' of neo-liberal growth and revealing it as legalised neo-imperialism.

    Thats what I reckon anyway!