Wednesday, 10 July 2019

The evolution of personality traits according to subsistence and mating strategies

Even though no human is like another one (not even identical twins), psychological analysis has shown that most human personality traits tend to cluster around five clusters, named OCEAN (openness, conscientiousness, extroversion, agreeableness and neuroticism) or FFM (Five Factor Model).  The British scientist Daniel Nettle has provided some interesting explanations for an evolutionary psychological perspective.

Some of these personality traits tend to be disadvantageous in our modern world: introversion (as the wonderful Susan Cain has been tirelessly been showing) correlates with less fulfilled social lives, lower income, fewer chances of promotion, and early retirement. Neuroticism and openness are correlated with psychological disorders (psychoses and neuroses, respectively) and low conscientiousness and low agreeableness is correlated with less education and higher crime rates.

As interesting Nettle’s ideas are, they do leave some room for further explanation. Where do the dimensions really come from? Are the traits still evolving or shifting towards one personality type?

What is interesting to note, is that the FFM does not work for all cultures. In many cultures there are fewer personality clusters and the first ones to disappear are openness (and with it the propensity towards psychosis) and neuroticism, which usually leaves E/A/C, or I/E, T/F, and P/J in Myers Briggs terms.

Hunter gatherers usually only show two clusters of personality traits, rather than five. One might hypothesize that personality could be strongly connected to subsistence, with two personality types in hunter-gatherer societies: “hunter” (most frequently probably male personality due to separation of labour) and “gatherer” (more prosocial, female type).  
Which modern personality type corresponds most with hunter-gatherer personality types? Thom Hartman has put forward the hypothesis that ADHD is essentially a hunter-gatherer trait. ADHD is most commonly associated with NP in Myers-Briggs.

With the advent of pastoralism and farming humans could acquire possessions and with them status and more access to mating possibilities with higher status.  Pastoralists and farmers would therefore contrary to hunter-gatherers seek higher status.  The difference between them would be along the C/J-P dimension, with pastoralists having more advantage if they are more exploratory and crafty P types and farmers being the more conscientious and hard-working J types.

Helen Fisher has studied online dating and has found out that certain personality types prefer to pair. Even though her personality types don’t correspond perfectly with either Myers-Briggs or Big 5, there is considerable overlap. She has found out that “explorers” (SP) tend to choose each other and the same is true for “builders” (SJ). However, “directors” and “negotiators” tend to pair up with  members from the other group. The four groups therefore would be:

In Myers-Briggs hunter and gatherers would be NT and NF types, pastoralists SP types and famers SJ types. Looking at the chart below we get the following types most frequently, supposedly also the most adapted by personality type: 
  1. Farmers (SJ) types, most adapted to modern lifestyle. Dominant hormone: serotonin
  2. Pastoralists (SP) types, moderately adapted to modern lifestyle: dominant hormone dopamine
  3. Hunters (NT) and gatherers (NF) types, least adapted to modern lifestyle: dominant hormone oxcytocin

Farmers and pastoralists would both be status-oriented, however farmers being more conscientious would be more successful in the modern world. Hunter and gatherer personalities would be least adapted to the modern world, as they are not programmed to achieve status in the form of accumulating goods, are more egalitarian, out-group social and might be more altruistic. In order not to be disadvantaged they would have to evolve defense mechanisms: introversion, social-vigilance (neuroticism) and openness to experience (which correlates with higher IQ) could be such defense mechanisms.