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Working together can hasten brain evolution, according to a new computer simulation.
When programmed to navigate challenging cooperative tasks, the artificial neural networks set up by scientists to serve as mini-brains "learned" to work together, evolving the virtual equivalent of boosted brainpower over generations. The findings support a long-held theory that social interactions may have triggered brain evolution in human ancestors.
"It is the transition to a cooperative group that can lead to maximum selection for intelligence," said study researcher Luke McNally, a doctoral candidate at Trinity College Dublin. Greater intelligence, in turn, leads to more sophisticated cooperation, McNally told LiveScience. [10 Fun Brain Facts]
It also leads to more sophisticated means of cheating, he added.
Virtual neurons
McNally and his colleagues used artificial neural networks as virtual guinea pigs to test the social theory of brain evolution. These networks are the numerical equivalent of very simple brains. They're arranged in nodes, with each node representing a neuron.
"In the same way that neurons excite each other via signals [in the brain], these nodes pass numbers to each other, which then decides the activity of the next node," McNally said.
The neural networks are programmed to evolve, as well. They reproduce, and random mutations can introduce extra nodes into their networks. Just as in real-world evolution, if those nodes are beneficial to the network, it will be more likely to succeed and reproduce again, passing on the extra brain boost.
The researchers assigned two different games for these networks to play, each an analogy for different social interactions. One, called the Prisoner's Dilemma, puts its participants in a scenario where cooperation is best for both parties but they still may be motivated to freeload. In the scenario, two suspects have been arrested for a crime. The police offer both a deal: Snitch on your partner and we'll give both of you a medium-length sentence. If you don't snitch, we'll easily convict you for a lesser crime, and you'll have to spend at least a little time in jail. But if you don't snitch and the other prisoner does, you're taking the fall — and you'll be in prison for a long time.
It's best for both parties to keep quiet, but each may be tempted to take the risk of snitching and hoping their partner is more noble.
In a second scenario, the snowdrift game, two partners have to work together to dig out of a snowdrift. The best choice from the point of view of one partner is to let the other do all the digging. But if both partners choose this route, neither is will get out of the snowdrift.
Artificial neural networks don't understand prisons or snowdrifts, of course, but they can be made to mathematically "play" these games, with winners getting a numerical payoff for avoiding a prison sentence or digging out of the snow. McNally and his colleagues set up 10 experiments in which 50,000 generations of neural networks got to work out these games. Intelligence was measured by the number of nodes added in each network as the players evolved over time. [10 Ways to Keep Your Mind Sharp]
Artificial brain boom
The simulations proved quite good at both the Prisoner's Dilemma and the snowdrift game, McNally said. They evolved strategies just like those seen when humans play these games with other humans.
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11 Comments
Add CommentDoes this mean that super social fauna such as ants have large brains in relation to their evolutionary advancement?
Reply | Report Abuse | Link to this<<Working together can hasten brain evolution,>> it says in the lead paragraph. So our actions can affect evolution? Doesn't sound right, but good for social engineering if true.
Reply | Report Abuse | Link to thisWhy wouldn't our actions affect our evolution? Changes in survivability are caused by different choices, and if enough creatures of a type choose a certain way, the population may favor that choice. Rather like the old adage about peacock male feather colors/length: that's driven by the choices made by the peahens. You can see it now in the USA - "dumb" is glorified culturally, so people choose to be "dumb" rather than excel at school, and we end up with a dumber population overall.
Reply | Report Abuse | Link to thisT
Yeah, I was wondering that too, so why aren't ants wearing fancy suits and drinking fine brandy? Chimps, from whom we supposedly sprang - I reckon, are a very social group; so why are they still running around naked and trowing sticks at each other? Why are they not capable of more advanced thinking, after all, they were here before us humans, weren't they?
Reply | Report Abuse | Link to this"Chimps, from whom we supposedly sprang - I reckon ... after all, they were here before us humans, weren't they?"
Reply | Report Abuse | Link to thisCommon misconception. See following link, drawings like the second diagram are mostly to blame for the misconception. The first and third diagram put things in context, modern humans did not evolve from chimps.
http://www.globalchange.umich.edu/gctext/Inquiries/Inquiries_by_Unit/Unit_5.htm
Re: "The findings support a long-held theory that social interactions may have triggered brain evolution in human ancestors."
Reply | Report Abuse | Link to thisWhat was the brain before in "evolved" into a brain? What mutation(s) caused it to "evolve?"
hi. This is an interesting observation and as an one of the authors of this work im dying to jump in!
Reply | Report Abuse | Link to thisThe answer lies in how related organisms are to their group mates. Bacteria are capable of high levels of cooperation, as are the ants and bees that you mention. When they form social groups, these species tend to have high relatedness to each other (often identical clones in the case of bacteria). This close familial relationship means that by helping or cooperating with a close relative, an individual can gain evolutionary fitness benefits via the offspring of a sibling (or clone). In this way, unconditional cooperation is relatively easy to explain - although you can still get cheaters in these societies. You dont need much intelligence for remembering who your neighbours are in these groups, as you can just assume they are a close relative every time you meet someone and just cooperate regardless.
The difference in say human or early-human societies (or dolphins, orca, primates etc...) is that relatedness is not enough to explain the level of cooperation we observe. The lack of relatedness (between full human siblings this is 50% genetic material shared) increases the likelihood of cheating and so its more tricky to explain why cooperation evolved and persists.
Our computer model had no element of relatedness in it at all so there was no benefit returned to an individual if a relative reproduced - in fact, there were not relatives as such at all in the model. Instead, we still observed cooperation emerging in spite of a lack of family relatedness and that a degree of intelligence is required to keep track of who you are interacting with, remember what they did you to historically and try to guess what they will do to you in the current round of the game.
hi Bill.
Reply | Report Abuse | Link to thisI guess this really ought to have read: "The findings support a long-held theory that social interactions may have triggered [exceptional] brain evolution in human ancestors."
What drove the evolution of central nervous systems is a whole other story, but they are ancestral and ancient and certainly all vertebrates possess a brain. The challenge i think is to understand why many vertebrates have large and/or complex brains capable of high level of problem solving. Many studies have shown a correlation between big brains and complex societies, but i think our model is the first to provide a mechanistic evolutionary story showing how and why this might occur.
- andrew jackson (co-author of the research)
Hi Andrew,
Reply | Report Abuse | Link to thisThank you for responding.
Prof. Richard Dawkins, in his book, "Blind Watchmaker" (if memory serves) wrote that biology is the study of complicated things that give the appearance of having been designed for a purpose. He rejected such observed phenomena as illusory. Is there an outside chance that the observations are not illusory, but reality?
Hi Bill,
Reply | Report Abuse | Link to thisThe brain is certainly a complicated and complex structure. Charting its evolution from simple clusters of light sensing cells towards a pituitary gland and then the aggregation of various neural processing nodes is straight forward enough from an evolutionary anatomical perspective. Comparisons across the range of animals gives insight to this process.
Prof Dawkins suggests that these complex structures can give the illusion of being designed with a purpose and a specific direction. In reality though a good understanding of the process of reproduction and the natural selection pressures shows us that no pre-determined design or purpose is necessary. Certainly our computer model clearly shows that complex neural processing structures can emerge spontaneously if they are allowed to evolve according to realistic biological constrains and principles.
Hi Andrew,
Reply | Report Abuse | Link to thisA computer model, less complex by magnitudes than any biological structure (i.e., the brain), is a result of pre-determined design or purpose. If computer models could spontaneously emerge, it seems to me, noone would need software engineers.
Regarding the value of natural selection, at least one botanist would seem to have been unimpressed:
"I have my doubts about one point in the concept [of] Neodarwinism...The problem is the origin of variability...The modern theory emphasizes the importance of genetic recombinations but ultimately rests upon mutations as the source of the variability acted upon by natural selection. This is where I run into problems...Could random changes in the nucleotide sequences of DNA (mutations) provide...(new) genes and ultimately the enzymes? At the moment I doubt it."
[Prof. Frank B. Salisbury. 1971. Doubts About the Modern Synthetic Theory of Evolution. THE AMERICAN BIOLOGY TEACHER, September, p. 335]