Monday, March 2, 2015

Virulence

I've just been reading this paper on evolutionary fitness with regard to time scale factors.  I was pleasantly surprised to find the infamous complexity theorist Bar-Yam as a co-author on the paper.

The main point they're resolving is how to treat scenarios where fitness measures on a short time scale fail to account for long time scale counter-fitness.  Their example is a pathogen.  If it is too transmissible, it dies out because of loss of suitable hosts.  If it is not transmissible enough, it also dies out.  They use equation based agent modelling as their methodology.

This leads to some possibly interesting analogies.  For instance, consider group collectives as a parasitic invader.

  1. If the parasite is too virulent, the host dies out.  
  2. If it is not virulent enough the parasite doesn't survive.  
  3. If the parasite has the right balance of virulence its population stabilizes.  

The corollary for group collectives goes as follows:

  1. If a group collective is too virulent, individualism dies out.
  2. If a group collective is not virulent enough, group collectives don't survive.
  3. If a group collective has the right balance of virulence, the prevalence of groups stabilize.
Now obviously parasites or group collectives have no awareness of "the right balance".  It's probably safe to assume virulence is normally distributed with selective pressure cutting off the tails.  So what causes virulent group collectives from taking over and eliminating individualism?  Do we just not have enough generational cycles to see this happening in humans?  

My thinking is that the freeloader problem is key.  Because individuals can dupe the group, there is selective pressure away from all powerful groups.  Trepidation is wise and signal sensitivity for freeloaders and non-adaptive groups are highly adaptive.

No comments:

Post a Comment