Regulatory Traits: Cultural Influences on Cultural Evolution

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A book chapter written (now almost two years ago…) by Magnus Enquist, Stefano Ghirlanda, and myself has just been published. It sums up pretty well part of the research I was carrying with the Centre for the Study of Cultural Evolution in Stockholm.

We explored the concept of “regulatory traits”, that is, cultural traits that are both socially transmitted (they are “cultural”), and influence directly (“regulate”) cultural dynamics. While the distinction between regulatory and non-regualtory traits is not always clearcut (potentially everything one learns could influence her future behaviour), the regulatory aspects of some traits seem particularly evident. For example, consider the regulatory trait “learning from school teachers”. This is both socially transmitted (parents do an effort to convince their children that learning from teachers at school is good) and influences directly – at least this is what parents aim for – cultural dynamics (children will listen to what teachers say at school). Again, teenagers may attempt to persuade their peers (“socially transmitted” part) to not listen to adults (“regulatory” part).

At a more abstract level, the same propensity to engage in cultural learning can be subjected to cultural influence and hence be a regulatory trait (you learn from others whether – or how much – to learn from others). Although this may seem not more than the starting of an headache-y riddle, we showed previously that, if this is the only force working in a system, the paradoxical result is that everybody will converge to not learn from other at all. Why is it so? “Conservative” individuals (i.e. individuals who do not engage in cultural learning) have indeed an inherent advantage as cultural models in respect to “open” individuals (i.e. individuals who engage in cultural learning): when a conservative individual will meet with an open one, it is more likely that the open will copy the conservative than vice-versa, pushing the population towards conservatism. Another way to think about this: imagine a group of, say, ten people, with t-shirts of different colours, playing the (well-known, of course) “copy the colour of my t-shirt” game. One of the individual will never copy others, while the other nine have a variable probability to engage in social learning. The only possible outcome of this game, given enough repeated iterations, is that everybody will end up wearing the same colour of the conservative individual, even if there is nothing in his t-shirt that makes it better than the others.

Even though the outcomes described above are the product of extreme, and scarcely realistic, conditions, regulatory traits-driven dynamics can interact with other aspects involved in cultural transmission, generating more complex, and – hopefully – interesting, outcomes (we explore, among others, in-group biases and fashion-like dynamics).  Conservatism itself is, in my opinion, an underestimated force with regard to the spreading of cultural traits. All other things being equal, a cultural trait that makes its bearers more conservative will be more likely to have success than a cultural trait that does not (I like to think in this term to the first of the ten commandments, which sounds “thou shalt have no other gods before me”, rather than “look around for other gods, and you’ll see I am the coolest”).

Moreover, a part from having effects in cultural dynamics, regulatory traits represent a difference between cultural and biological evolution. This is an “hot” topic in modern cultural evolutionary theory so I do not want to go in depth here (let me just say at least that I think it is interesting to study also the differences between the two evolutionary processes). “Rules” of genetic transmission tend to not be under genetic control, and models of cultural evolution inspired by evolutionary biology tend to consider the rules of cultural transmission (for example the propensity to learn from others) in the same way not under “cultural control” (they are usually considered under genetic control). However, the fact that cultural information can be transmitted in many different ways creates the opportunity to regulate the flow of information in a fine–grained and context–dependent way, and regulatory traits can have a role in this process.

Much more on all this on our chapter (you can find it here, or a preprint here).

Reference

Acerbi A., Ghirlanda S., Enquist M. (2014), Regulatory traits: Cultural Influences on Cultural Evolution, in: Cagnoni, S. et al. (Eds.), Evolution, Complexity, and Artificial Life, Springer, pp. 135 – 147

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2 thoughts on “Regulatory Traits: Cultural Influences on Cultural Evolution”

  1. Surely, everyone believes that the rules of genetic transmission are under genetic control! Probably, you are talking about how easy the rules are to change by making genetic modifications.

    Note that, if you are comparing genetic with cultural evolution, you should really be looking at whether the capacity of organisms to transmit DNA-based symbionts (e.g. gut bacteria, and parasites) is easy to change by making genetic modifications. In which case, you will see that the way in which such genes are transmitted is relatively malleable. It is easy enough for genetic changes to make an organism more or less likely to sneeze, for instance.

    If you adopt this perspective on evolution in the organic realm, you will see that the case of DNA-based symbionts turns out to be closely comparable to the case of cultural symbionts – with respect to how easy it is for DNA to modulate the transmission pathways involved.

    If anyone has ever reasoned from organic evolution to cultural evolution – arguing that since genetic transmission is not easy for genes to regulate cultural transmission will not be easy for culture to regulate cultural transmission – then probably their understanding of the dynamics of genetic transmission is faulty. There’s no need to question their understanding of the relationship between organic evolution to cultural evolution on these grounds – since this is an example of where these processes are very similar. There are, in fact, plenty of known cases where genes can easily regulate the transmission pathways of other genes residing in symbionts.

    1. Hi Tim,
      thank you very much for your input.
      In the post I squeezed our argument in just few sentences, but I invite you to have a look at the pdf linked above, where we expand it some more.
      To me, the problem is mainly pragmatic (i.e. how much complexity do you want to put in your models of [cultural/genetic] evolution?). Population genetic has been built on models that make the simplifying assumption that rules of genetic transmission are immutable, and this strategy has been proved successful. The question we ask in the paper is whether the same simplifying assumption can be safely made in models of cultural evolution.
      More generally I do not see this as black/white distinction. I agree that genes can and do regulate their transmission pathways, but I think that in cultural evolution this effect is way more important.

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