The evolutionary psychology of personality

Scientists used to think that the human mind was a blank slate (John Locks’s famous tabula rasa) which was written on by culture. However, evolutionary psychology and increasingly genetics are disproving this idea. A lot of traits have a genetic component, e.g. how conscientious a person is, their parenting style, or whether they are night owls or early birds.

Evolutionary psychologists used to believe that everybody is a hunter-gather psychologically speaking. However, that is not true. The few thousand years since the time farming was invented did have a genetic impact. Farmers compared to hunter-gatherers needed to be more hard-working, more conscientious (cf. Daniel Nettle) and more defensive of their property. On the flip side, they have become less generous (but only to outgroup members), less egalitarian and more status-seeking (accumulated wealth allowed for status). As William von Hippel points out in his great book “The Social Leap” the highly sharing and caring hunter-gatherer attitude towards everybody in the group would have been highly disadvantageous for early farmers.  

Farming would have involved quite a lot of cognitive, personality and behavioral changes. Strong focus on work, routine and conscientiousness were among them. Hunter-gatherer, on the other hand, needed to be more flexible and vigilant. Thom Hartman argues that ADHD is a manifestation of the hunter-gatherer mind, which is easily distractible (potential dangers, etc.) but has the ability to hyperfocus. Unfortunately, in our modern world ADHD minds often become dysfunctional as a farmer mind would obviously be much more adapted to a 9-5 job or a long school day than a hunter-gatherer mind. Sleep patterns might be part of the package: hunter-gatherers needed to be flexible, whereas for farmers is was more advantageous to get a good night's sleep and rise with the sun. Night owls are therefore more likely to have inherited a hunter-gatherer mind than early risers.

Another problem for early farmers would have been parenting and teaching. As Peter Gray shows in his highly recommendable book “Free to Learn” hunter-gather children spend most of their time playing, thus learning everything they need as grown-ups through peer-learning and self-directed learning. My hunch is that the majority of kids with oppositional defiant disorder in addition to those diagnosed with ADHD and a tendency to be autodidacts in schools have inherited hunter-gatherer minds, whereas the ones who easily adapt to the school system have inherited farmer minds. For farmers it was probably highly important to formally teach their children early on so they could help with the many daily chores.

Not only children are treated in this egalitarian way, but also women are considered equal and not supposed to be submissive to their husbands. There is no concept of “pater familias” and there is less sexual dimorphism than in farmer societies, which can not only be seen in cultural artifacts (e.g. fewer and less opulent jewelry) but also physically as men don’t show typically male digit ratios.

The following table shows a list of traits typical for hunter-gatherer vs. farmer minds. All of them have been found to have a genetic component. Of course, also mixed traits occur and culture and an individual’s life trajectory might override genetic tendencies.  

hunter-gatherer	farmer
High on personality trait “openness”, low on “conscientiousness”	High on personality trait “conscientiousness”, low on “openness”
Strongly (actively) egalitarian	status-seeking
Tendency towards out-group sociality, more accepting of diversity (e.g.  different sexuality, refugees, etc.)	Tendency towards in-group sociality (identifies more strongly with a core group, like family, religious group or sports team)
More liberal ideology	More conservative ideology
Less sexual dimorphism	More (display of) sexual dimorphism
Later onset of puberty	Earlier onset of puberty
More monogamous tendencies	Less monogamous tendencies
Tendency to wanting fewer children	Tendency to wanting more children
Relaxed child-rearing attitude	Authoritative child rearing, “helicopter parenting”
Night owls	Early risers
“Lazier” (when it comes to physical work and chores)	More hard-working
highly rebellious when feeling personal freedom and values are threatened	individualistic, but also more conformist and highly loyal to their core group
Less interest in small-talk and gossip	Higher interest in small-talk and gossip

There is a third group of personality type: pastoralists, who have mixed traits and the earliest onset of puberty. The three groups show an r/K-selection range. They are also distinguishable by facial features. 

Hunter-gatherers: rectangular face shape for hunters, heart-shaped face for gatherers (male and female patterns are often reversed in modern hunter-gatherer personalities, i.e. females can have rectangular facial shape and males the heart-shaped form. They, therefore, tend to pair in all possible varieties: hunter-gatherer, hunter-hunter and gatherer-gatherer.

San hunter (rectangular face) and gatherer (heart-shaped face) 

Richard Dawkins (hunter) and Lala Ward (gatherer) paring, two soulmates

Pastoralists have oval-shaped faces.

Datoga and Maasai pastoralists: oval faces.

Paul and Linda McCartney: oval faces, artistic personality types (ISFPs), two playmates, a turbulent but successful marriage.

Farmer types tend to be more serious and hard-working. They have typically square or round faces:

African farmers with square/round faces

Geroge W. and Laura Bush, square/round farmer faces