According to scientists (e.g. Del Giudice Evolutionary Psychopathology) life history has a huge influence on personality traits, e.g. longer lifespans would entail later sexual maturity, more parental investment and less risky behavior. Life spans in our evolutionary past varied according to our ancestors' mode of subsistence.
Semi-nomadic pastoralists and horticulturalists have the shortest average life span at approximately 31 years, followed by highly mobile hunter-gatherer societies at 38.5 years, and sedentary agricultural communities at 52.2 years. (Barbara R. Hewitt, 2003)
There are, however, many indications that for early farmers life was harder and probably shorter than those of hunter-gatherers, even though people in more modern agricultural societies live longer. It isn’t hard to see those early farmers easily outbred hunter-gatherers due to higher fertility rates even though they might have had shorter life-spans.
There are plenty of indications that pastoralists, who experience a lot of violence and instability had the shortest lifespans. It is likely that evolution entrenched adaptive traits genetically, e.g. farmers with higher levels of serotonin (conscientiousness and future-oriented planning) were more successful. For pastoralists, whose lives were shorter, taking risks (dopamine) would have been advantageous for survival and mating. For hunter-gatherers, a childlike openness for learning in new environments and humbleness for a non-violent co-existence would have been the most advantageous personality traits.
We can assume that in many places over the world these types interbred. E.g. in Europe early farmers interbred with European hunter-gatherers and later Indo-European and other step pastoralists (Huns, Turkic peoples, Magyars, etc.). Their personality traits also mixed, but there are genetic hints that different personality types tend to choose their friends and partners from their own group. This would prevent total mixture and making sure that some traits occur in clusters.
r/K theory and life history studies would predict the following traits:
Shortest lifespan (pastoralist)
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medium (farmer)
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Long lifespan (HG)
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Most risk-taking/least fearful
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Least risk-taking/most fearful
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Earliest onset of puberty
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Latest onset of puberty
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Many offspring
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Few offspring
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Least paternal investment
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Most paternal investment
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Most sociosexual
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Most pair-bonded
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Higher sexual dimorphism
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Lower sexual dimorphism
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Most in-group social
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Most out-group social
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Del Giudice writes Evolutionary Psychopathology that trait “openness” is negatively correlated with fertility for people reaching their sexual maturity from the advent of the pill in the 1960s. As I have written in previous posts, hunter-gatherer personalities want to have fewer children, in particular in the absence of the typical social network (it takes a village to raise a child). On the other end of the life-history spectrum for pastoralist types, it seems likely that they prefer not to have children due to commitment-phobia.
Our society with its 9-5 jobs is very much a farmer society and it can, therefore, be safely inferred that it is farmer types who are best adapted to our modern world and that pastoralists and hunter-gatherer types experience more health and mental problems.
I have argued that both gifted and autistic people belong to the hunter-gatherer group showing the following common K-selected traits:
- Picky eating in childhood
- Highly sensitive (to noise, light, etc.)
- Later onset of puberty
- Neotenous traits (from being more childish, emotionally less mature to looking younger and having “delayed skeletal development)
- Prone to anxiety, in particular, social anxiety
- Prone to depression
- ADHD and hyperfocus
- Lower sexual dimorphism