Monday, 28 December 2015

Answers for Doug Hoxworth

Doug Hoxworth had some questions which he aired in public recently:

  • If transmission only happens based on the “selfish” gene theory, how do behavioral or personality traits that are advantageous for the group but disadvantageous for the individuals within the group ever get transmitted to the next generation and become dominant/ubiquitous? If it is heritable, how can this phenomenon be explained?

    • Kin selection. For example, worker sterility is disadvantageous to the worker as an individual, but beneficial to the group they are part of. The reason for this is because the worker and the reproductives (queens and drones) share genes. It is possible to explain this in terms of group selection as well. However group selection explanations often turn into simplistic group-level functionalism - whereas kin selection quantifies relatedness (using 'r') and so is a better tool for making quantitative predictions with - in those cases where relatedness is less than 1.

  • How can altruism to non-relatives be explained?

    • For humans, the most significant mechanisms are probably cultural kin selection, virtue signaling, manipulation, over-generalization and environmental mismatch - in roughly that order.

  • If it is through enculturation and imitation, how are these behaviors so ubiquitous at a very young age, if not at birth (even applicable to animals/organisms other than humans that presumably do not emit pheromones indicating that they are unambiguously related, e.g., ants)?

    • Cultural transmission is often advantageous to individuals. Using socially-transmitted information from others can give a short-cut to learning - if maladaptive traditions can be avoided. There are various ways of avoiding maladaptive traditions.

Doug's article contrasts group selection with the selfish gene. In fact these ideas are compatible. The selfish gene is compatible with kin selection and it is compatible with group selection. Richard Dawkins might not agree - but we don't need to heed him here. The disagreement in this area mostly lies elsewhere.

The problem with group selection is not so much that it's wrong, but that it causes confusion among its practitioners. For decades group selection advocates held out hope that their theory would make novel predictions. In the last decade, this hope has mostly collapsed and most now recognize that group selection and kin selection are broadly equivalent. It is a matter of different accounting techniques, so to speak.

The main problem is that we know that kin selection is strongest between close relatives. Group selection advocates often want to apply the theories to whole tribes and to warfare. This sort of group selection isn't equivalent to kin selection - and, for the most part, it doesn't actually work.

What is left of this whole debate? Not too much. There's some noise surrounding Hamilton's inclusive fitness concept, but this is mostly coming from Martin Nowak and friends - and his papers have been met with ridicule. At this stage, most of the facts seem to be in and the group selection controversy resembles a mopping up operation.