The evolution of intuitive, gifted and autistic personality traits and a dual reproductive strategy (OXTR gene)

The Jungian personality category of intuitives ((over)thinkers, abstract minded, often clumsy people) vs sensors (practical, more down-to-earth people) unfortunately is currently not reflected in any scientific model of personality (Big 5, OCEAN).

As intuitives and sensors often have communication problems due to differences in perceiving the world, they sometimes don’t mix well. Intuitives are known to have these characteristics:

• (over)thinkers
• heightened sense of justice (particularly justice for all)
• a host of cognitive problems like forgetfulness (think distracted professor)
• little respect for traditions
• very curious and open minded
• often gifted
• often also neurotic
• clumsy and/or accident prone (due to having their head in the clouds)
• often socially awkaward

Being an intuitive myself many of my friends and acquaintances (particularly online) I have been able to observe the following traits:

• are averse to in-group thinking and discrimination (sexism, racism, homophobia, etc;)
• have an above average sense of humour
• are averse to marriage/having children in unsettled times
• are often late bloomers
• have neotenous traits and are often considered “big children” by non-intuitives
• typically want no/few children or children later in life
• laissez-fair parenting style (probably due to being collective breeders, see bellow)

All this has led me to conclude that the intuitive character trait is only secondarily about cognition, but primarily about social behaviour and reproductive strategies. In brief:

Intuitives are slower breeders (than sensors/GG gentoype) with more monogamous tendencies and higher parental, in particular paternal investment and a tendency to collective child rearing.

One recent study even claims that oxcytocin plays in important role in the longevity of marriages. This makes sense, when one considers that neoteny might play a key role in increased cognitive openness and learning and AA/AG offspring would require longer parental care than GG children. I wouln't be surprised if the AA/AG was involved in human longevity in general, as is typically the case for slow breeders. It has been known for a while that women who give birth at an older age live longer. To my mind, there is no causality here, just a correlation due to the fact that AA/AG carriers tend to postpone child bearing.

Why has this mode of reproduction evolved? The answer is simple: to guarantee the survival of offspring in extremely hard times or under extremly harsh conditions. Under such conditions it is best for all to cooperate and to avoid inter-group conflict and fights for hierarchical positions. The problem with this hyper social mode is potential parasitic behaviour by non-intuitives. In order to sustain this mode of reproduction intuitives need to

• Boost their general intelligence to detect parasites
• Be averse to in-group thinking to avoid conflict and hijacking
• Have a heightened sense of justice

Some of the cognitive trade-offs might include

1. Forgetfulness (particularly of practical things)
2. Worse memory performance for everyday occurrences
3. Worse episodic memory
4. Worse attention to surroundings, decreased vigilance

Once a physiological basis for this behaviour is found, the hunt for the genetic foundation can start. Obviously, oxytocin (the cuddle/monogamy/breastfeeding/laughter hormone) seems to play a dominant role in in this reproductive strategy. The first obvious choice for a gene is OXTR rs53576 with its three genotypes GG, AG and AA.  The following table provides a genetic study of allele frequencies.

		Frequencies
		Allele			Genotype
rs53576
Population	Number	A	G	Number	AA	AG	GG
African All*	1194	0.224	0.776	597	0.057	0.333	0.610
Americans of African Ancestry in SW USA	122	0.287	0.713	61	0.082	0.410	0.508
Luhya in Webuye, Kenya	198	0.211	0.789	99	0.052	0.320	0.629
Yoruba in Ibadan, Nigeria	216	0.193	0.807	108	0.045	0.295	0.659
Hadza, Tanzania	270	0.426	0.574	135	0.148	0.556	0.296
Datoga, Tanzania	388	0.302	0.698	194	0.077	0.448	0.474
American All*	524	0.343	0.657	262	0.116	0.453	0.431

The Hadza and Datoga are highlighted, because they have very different social organizations. The Hadza are monogamous, egalitarian hunter-gatherers (most frequent genotype AG), whereas the Datoga are stratified, polygynous pastoralists (GG dominant) and personal wealth clearly correlates with reproductive success.

What is interesting to note, is that the relatively rare AA type can thrive only in a population with higher AG types. AA types are highly innovative individuals who sacrifice social cognition in favour of general cognition (interest in gossip, forget names, even risk autism, ADHD and prosopagnosia - yes, I am thinking of you, professor Norbert Wiener and you, Oliver Sacks, my personal heroes). Such a gentotype can only thrive if the indivdual is integrated and appreciated for their innovative social contributions. If this is not the case these indivuals develop a host of mental problems. This is exactly what we see with ASD and gifted orchid children who fade away. At at time when deep social connections are becoming increasingly rarer AA/AG types are bound to suffer from all kinds of mental illnesses with depression on the forefront.

These genotypes correlate highly with the intuitive/sensor phenotypes:

GG = probably ES types (extraverted sensors)

AG = probably EN and IS types (extraverted sensors and introverted sensors)

AA = probably IN tpyes (introverted intutives) (the numbercorresponds roughly to the 10% introverted intutives in the population in Myers-Briggs statistics).

Of course, GG types are also very social, in many ways more social and helpful than AA types (think of a fireman, extraverted host of a party). However, they are social in a more in-group way. Both intuition and introversion serve as isolation mechnisms. However, AG types can mingle with both types with extraverted intutives probably having a preference for AA types and introverted sensors probably a preference for GG types.

A typical INTP type (e.g. Einstein, Darwin) with high propensity towards procrastination could therefore end up as a scientist/professor, taxi driver or a hobo or an autistic person at the edge of society.

AA/AG types prefer to mate with other AA or AG types. This could potentially explain the high occurrence of ASD (Asperger’s) in Silicon Valley. Even though AA types are very rare, you will find a lot of these innovative people working a Google and other innovative high-tech companies.

A historic note: AA/AG types might have been prevalent during the evolution of homo. Neanderthals probably had prevalent AA/AG types. They also preferred to live in smaller groups than homo sapiens (about 150/Dunbar’s number) as bigger groups have a higher potential for conflict. The Hadza also have a tendency to split up when social conflict arises.

Right now, we can see this tendency to slit up in election results all over the industrialized world. GG types preferring a hierarchical order and thus voting for politicians like Trump (ESTP in Myers Briggs) or Theresa May (ESTJ), conservative, hierarchical leaders.  

GG types might have become more prevalent with the spread of farming when it was possible to accumulate personal wealth. It should be possible to prove this genetically, and I am personally looking forward to David Reich and Svante Pääbo do so.

Dedicated to Sophia and Marisa, my daughters

The genetic part (even though probably pretty flawed) is dedicated to Svante Pääbo, David Reich and Luigi Luca Cavalli-Sforza, my geneticist heroes. I am personally immensely grateful to Svante Pääbo for proving that Neanderthals probably had very human like speech due to the FOXP2 gene.  I tried to prove this in my PhD thesis in 2000, but none of my university supervisors believed me due to a lack of empirical evidence.


Appendix:

Here is an overview of the genotypes (from this source):

Mechanism:

GG promotes the efficient functioning of the oxytocin system and enhances the effects of oxytocin supplementation. (R) The gene frequency varies by race: ~61% of Africans have it (in Africa), ~41% of Europeans (~30% of Finns)and ~10% of Asians. (R)

The Minor "A" allele is associated with:

• AA and AG individuals were judged to be less pro-social and displayed fewer nonverbal cues compared to GG people. The study suggested that the association between and prosociality was stronger for men, but also true for women. (R)
• GG are better at accurately reading the emotions of others by observing their faces. (R) compared to AA or AG. GG was more mellow and more attuned to other people than were the AA or AG.(R)
• In response to an interview, GG or AG had significantly lower cortisol responses to stress when they had social support. There were no differences in cortisol levels in subjects with the AA genotype receiving or not receiving social support. The AA genotype tended to have higher levels of cortisol throughout the session than G carriers (no differences between the genotypes were observed at baseline). (R)
• GG was less empathetic to pain experienced by racial 'out group' vs racial 'in group' members (Asians vs Whites). However, AA experienced more pleasure from pain to racial out-groups. (R)
• So GG cares less about other races or who they view as 'other' (including competitions), but AA experiences more schadenfreude, which is pleasure at out-group pain or downfall.(R)

The Major "G" allele is associated with:

• GG have a more positive 'affect' or disposition (R). AA and AG individuals were judged to be less pro-social and displayed fewer nonverbal cues, head nods and smiles compared to GG people. The study suggested that the association between and prosociality was stronger for men, but also true for women (R).
• GG are more optimistic (R)
• GG are more empathetic (R)
• GG handle stress better (R)
• GG are better at accurately reading the emotions of others by observing their faces (R) compared to AA or AG.
• GG are less likely to startle when blasted by a loud noise, or to become stressed at the prospect of such a noise (R)
• GG was more mellow and more attuned to other people than were the AA or AG (R)
• GG have a higher Verbal IQ (R)
• GG feel less lonely (R)
• GG was less likely to seek support from their peers (R)
• GG employ more sensitive parenting techniques (R)
• GG have lower rates of autism (R)
• GG have less difficulty hearing and understanding in noisy environments (R)
• In response to an interview, GG or AG had significantly lower cortisol responses to stress when they had social support. There were no differences in cortisol levels in subjects with the AA genotype receiving or not receiving social support. The AA genotype tended to have higher levels of cortisol throughout the session than G carriers (no differences between the genotypes were observed at baseline) (R)
• GG have more gray matter volume in the hypothalamus and greater hypothalamus volume and more activation in the amygdala (R)
• GG are less predisposed to major depression (R)
• GG take social rejection worse than others. GG had higher blood pressure and cortisollevels the following rejection, effects not apparent among A carriers. (R)
• GG was less empathetic to pain experienced by racial 'out group' vs racial 'in group' members (Asians vs Whites). However, AA experienced more pleasure from pain to racial out-groups. (R)
• So GG cares less about other races or who they view as 'other' (including competitions), but AA experiences more schadenfreude, which is pleasure at out-group pain or downfall.(R)