29 Oct

Honest Signal

Honest Signal

There is a term called “honest signalling” in evolutionary biology.  It is not a new insight, but it is going to form basis for some of the key discussions we are going to have in the future.

Peacock’s tail is a wonderful example of a honest signal.  The luxury of the tail fathers correlates well with the fitness level of the animal which carries it.  A peacock with lower fitness can’t fake a luxurious tail feathers.  So, peahens have come to use the fitness of the tail feathers as a primary mate selection criteria.

Gazelles are known to stot (quadruple jumping) in the presence of a predator.  By stotting, the gazelles  signal their fitness level to the predator (Hey, look, I am very fit.   No use chasing me.  Find someone else easy).  As a weaker animal can’t stot as well as a fitter animal, stotting turns out to be a honest signal.

In humans, wealth indicators are easily understandable honest signals.  A Rolls Royce car is a honest signal of one’s financial resources.  Or, a Nobel prize is a reliable indicator of one’s mental resources.  Great skin, shining nails or lustrous hair is a honest signal of someone’s physical fitness.  But with humans, there is one ‘not so obvious’ fitness indicator: The Brain!

While a Nobel prize might be a reliable indicator of one’s cognitive resources (but then again, several Nobel prize winners had notoriously troubled family lives), brain itself is thought of as a honest signals of an individual’s genetic fitness.  In a wonderful book Mating Mind (which has cart load of politically incorrect assertions), Geoffrey Miller claims that the large humans brain evolved as a honest signals of genetic fitness.

No other animal has evolved large brain because large brain is a pain.  Consider these:

  • Large brain is simply redundant for eking out a life on this planet.  After all, none of the other animals have bothered to evolve a large brain.
  • Our brain is metabolically very expensive.  We end up spending about one fifth of our energy budget on the upkeep of the brain.
  • Large brain makes child birth a very risky venture for both the mother and the child.
  • Large brain made it difficult and awkward for us to move quickly like most of our primate cousins could.

A large brain has loaded us with plenty of disadvantages.  There must have been some compelling evolutionary advantage that the large brain brought us.  Otherwise, evolution would have weeded it out.

If we think that the intelligence of a large brain gave us any survival advantage, you may  be wrong.  After all, till the advent of agriculture, our life was hardly any different from that of any other animal on the planet.  We were not even the top predators on earth, even though we evolved our large brains some 200,000 years ago!  Why did we go through so much of trouble and evolve such large brain if it didn’t afford us any survival advantage?

Geoffrey Miller argues that a large brain evolved as a honest signal of the genetic fitness of the individual who carries it.  So, we have probably come to regard all ‘products of mind’ highly.

This has several interesting implications.  We will address them tomorrow.

One thought on “Honest Signal

  1. Pingback: Yes- another day, another positive “All Yesterdays” book review | What's In John's Freezer?

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