family types and the selection for nepotistic altruism

it finally clicked in my head while thinking about polygamy what the importance of family types — nuclear vs. extended, etc. — might be in the selection for altruistic behavioral traits, especially nepotistic altruism or clannishness. i should’ve thought through polygamy sooner instead of putting it off, but hey — procrastination is heritable, too, so in the words of h. solo, it’s not my fault! (~_^)

the logic of the mating patterns/inbreeding-outbreeding theory goes that, given the right set of circumstances (i.e. certain sorts of social environments), selection for nepotistic altruism/clannishness ought to go quicker or be amplified by inbreeding (close cousin marriage or uncle-niece marriage) simply because there will be more copies of any nepotistic altruism genes (alleles) that happen to arise floating around in kin groups. in other words, inbreeding should facilitate the selection for clannishness…if clannish behaviors are being selected for in a population.

the thing is, though: the individuals carrying certain versions (alleles) of nepotistic altruism genes need to direct their nepotistic behaviors towards other individuals carrying those same alleles, otherwise their actions will be for naught. (yeah. kin selection.) if they direct their nepotistic actions towards people who don’t share the same alleles, then the actions will be “wasted” and the behavioral traits won’t be selected for — or at least not very strongly — and they might fizzle out altogether.

let’s take an imaginary society as an example: say everyone in our pretend population always marries their first cousins. their father’s brother’s daughters (fbd) even, so that we get a lot of double-first cousin marriage. h*ck! let’s throw in some uncle-niece marriages on top of it all. the inbreeding coefficients in such a society would be very high, and if clannishness was being selected for in our highly inbred population, the selection ought to move pretty quickly.

but suppose we separated all the kids at birth from their biological families and set them out for adoption by unrelated individuals — people with whom they likely did not share the same nepotistic altruism alleles. think: the janissary system, only on a population-wide scale. if we did that, there should be virtually no selection for clannishness despite all the inbreeding since pretty much no one’s nepotistic behaviors would be directed towards other individuals with the same nepotistic altruism genes. in this case, kin selection would just not be happening.

such a society does not exist, and i don’t think ever has. but there are societies out there with certain family types — namely nuclear families (or even post-nuclear family societies!) — which ought to have a similar dampening effect on any selection for clannishness.

northwestern “core” europe has had very low cousin marriage rates since around the 800s-1000s, but it has also, thanks to manorialism, had nuclear families of one form or another (absolute or stem) since the early medieval period — nuclear families are recorded in some of the earliest manor property records in the first part of the ninth century from northeastern france [see mitterauer, pg. 59]. on the other hand, eastern europeans, like the russians and greeks, while they also seem to have avoided very close cousin marriage for several hundreds of years (which is not as long as northwestern europeans, but is quite a while), have tended to live in extended family groupings. you would think that nepotistic altruism could be selected for, or maintained more readily, in populations where extended family members lived together and interacted with one another on a more regular basis than in societies of nuclear family members where individuals interact more with non-kin. societies comprised of nuclear families are more like my hypothetical janissary society above where the altruism genes that might’ve been selected for via kin selection instead fade away in the wash.

we have to be careful, though, in identifying nuclear family societies. the irish of today, for instance, are typically said to be a nuclear family society, but the extended family does still interact A LOT (i can tell you that from first-hand experience). same holds true for the greeks and, i suspect, the southern italians. i would say that these populations have residential nuclear families, but not fully atomized nuclear families which have infrequent contact with extended family (think: the english). the early anglo-saxons in england were also characterized by residential nuclear families — the extended family (the kindred) was still very important in that society. the individuals in a residential nuclear family society probably do interact with non-family more than individuals in a society structured around extended families or clans, but less so than a true nuclear family society.

the thought for the day then?: family types can also affect the selection for clannishness/nepotistic altruism.

that is all! (^_^)

previously: polygamy, family types, and the selection for clannishness and “l’explication de l’idéologie”

(note: comments do not require an email. irish nuclear family.)

linkfest – 10/11/15

Ancient Ethiopian genome reveals extensive Eurasian admixture throughout the African continent“Here, we present a 12.5x coverage ancient genome of an Ethiopian male (‘Mota’) who lived approximately 4,500 years ago. We use this genome to demonstrate that the Eurasian backflow into Africa came from a population closely related to Early Neolithic farmers, who had colonized Europe 4,000 years earlier. The extent of this backflow was much greater than previously reported, reaching all the way to Central, West and Southern Africa, affecting even populations such as Yoruba and Mbuti, previously thought to be relatively unadmixed, who harbor 6-7% Eurasian ancestry.” – h/t john hawks! who tweeted: “First ancient DNA from Ethiopia shows that today’s sub-Saharan Africans are at least 0.2-0.7% Neanderthal ancestry!” – see also: First Ancient African Genome Reveals Vast Eurasian Migration“The man’s genome is, unsurprisingly, more closely related to present-day Ethiopian highlanders known as the Ari than to any other population the team examined, suggesting a clear line of descent for the Ari from ancient human populations living in the area. But further genetic studies show that the Ari also descend from people that lived outside Africa, which chimes with a previous study that discovered a ‘backflow’ of humans into Africa from Eurasia around 3,000 years ago.”

Eight thousand years of natural selection in Europe“The arrival of farming in Europe around 8,500 years ago necessitated adaptation to new environments, pathogens, diets, and social organizations…. We identify genome-wide significant signatures of selection at loci associated with diet, pigmentation and immunity, and two independent episodes of selection on height…. These results suggest that the modern South-North gradient in height across Europe is due to both increased steppe ancestry in northern populations, and selection for decreased height in Early Neolithic migrants to southern Europe. “

The Hybrid Origin of “Modern” Humans“Recent genomic research has shown that hybridization between substantially diverged lineages is the rule, not the exception, in human evolution. However, the importance of hybridization in shaping the genotype and phenotype of Homo sapiens remains debated. Here we argue that current evidence for hybridization in human evolution suggests not only that it was important, but that it was an essential creative force in the emergence of our variable, adaptable species.”

Neanderthal ‘flower children’ burials theory debunked“New research casts doubt on the idea that Neanderthals buried their dead covered in flowers.”

Intelligence in youth and health at age 50“Higher intelligence in youth is linked with better physical health at age 50.” – h/t andrew sabisky!

Chorionicity and Heritability Estimates from Twin Studies: The Prenatal Environment of Twins and Their Resemblance Across a Large Number of Traits“There are three types of monozygotic (MZ) twins. MZ twins can either share one chorion and one amnion, each twin can have its own amnion, or MZ twins can—like dizygotic twins—each have their own chorion and amnion. Sharing the same chorion may create a more similar/dissimilar prenatal environment and bias heritability estimates…. We conclude that the influence on the MZ twin correlation of the intra-uterine prenatal environment, as measured by sharing a chorion type, is small and limited to a few phenotypes.”

Genetic transmission of reading ability – h/t steve stewart williams! who tweeted: “If you want your kids to read, your best bet is to have kids with a reader.”

It All Began at Ararat, and Esau’s Revenge“Ancient DNA in Europe strongly indicates massive replacement [of hunter-gatherers by agriculturalists]. But, there is also suggestion of admixture with the local substrate. And, unlike the stylized model of Bellwood, it seems that there were multiple migrations after the initial pulse which reshaped the genetic and cultural landscape of human societies in the wake of agriculture.” – from razib.

Closing the Black-White IQ Gap Debate, Part I – from chanda chisala. and a response from peter frost: No, blacks aren’t all alike. Who said they were? – and previously on this blog: there’s more to human biodiversity than just racial differences.

The Association of Cognitive Ability with Right-wing Ideological Attitudes and Prejudice: A Meta-analytic Review“The present meta-analyses revealed an average effect size of r = −.20 [95% confidence interval (95% CI) [−0.23, −0.17]; based on 67 studies, N = 84 017] for the relationship between cognitive ability and right-wing ideological attitudes and an average effect size of r = −.19 (95% CI [−0.23, −0.16]; based on 23 studies, N = 27 011) for the relationship between cognitive ability and prejudice.”

[male] Chimps like boys toys too“If you want to know why young boys play with toy guns, you could do worse than consider why young male chimpanzees play with leaves and stones.” – h/t darren burke! who tweeted: “Western social constructivism is so insidious and widespread it is even affecting wild chimpanzees now!” – (~_^)

Ravens cooperate, but not with just anyone“Ravens detect cheaters in cooperation.”

Understanding the Cognitive and Genetic Underpinnings of Procrastination: Evidence for Shared Genetic Influences With Goal Management and Executive Function Abilities – procrastination (at least) 28% heritable. will have to read original paper. tomorrow, maybe. (~_^)

Personality Traits Increasingly Important for Male Fertility: Evidence from Norway“[P]ersonality relates to men’s and women’s fertility differently; conscientiousness decreases female fertility, openness decreases male fertility and extraversion raises the fertility of both sexes. Neuroticism depresses fertility for men, but only for those born after 1956.”

Host genetic variation impacts microbiome composition across human body sites“Our results highlight the role of host genetic variation in shaping the composition of the human microbiome, and provide a starting point toward understanding the complex interaction between human genetics and the microbiome in the context of human evolution and disease.”

DNA At the Fringes: Twins, Chimerism, and Synthetic DNA – h/t genetics and society! who tweeted: “Chimeras could undermine DNA forensics & use of DNAtesting as conclusive proof of crime & family.”

Ethnic differences in the association between depression and chronic pain: cross sectional results from UK Biobank [pdf] – h/t don lyall!

Emotion, rationality, and decision-making: how to link affective and social neuroscience with social theory

Women and men react differently to infidelity“While men are most jealous of sexual infidelity, women are most jealous of emotional infidelity.” – w.e.i.r.d. study. (n=1000).

‘Safe spaces’ exist because universities treat secular ideas as sacred“The most influential effect of this cultural and political imbalance is that academia has ignored the increasing evidence that human traits are heavily influenced by hereditary factors, most prominently in intelligence and sexual differences. This has a huge bearing on public policy, especially when so much of policy is involved in tackling inequality of various kinds. It would be like trying to reduce economic inequality while pretending that wealth cannot be inherited, because that’s offensive to people’s parents, and that all fortunes were the results of education, hard work or sheer luck.” – from ed west.

Relics of the Blank Slate, as Excavated at “Ethics” Magazine“There’s a reason that the Blank Slaters clung so bitterly to their absurd orthodoxy for so many years. If there is such a thing as human nature, then all the grandiose utopias they concocted for us over the years, from Communism on down, would vanish like so many mirages.” – from helian.

Anthropologist: “I’ve Never Been So Disgusted with My Own Data” – from steve sailer.

“Ethics” is advertising – david chapman on virtue signaling (trans: signalling. (~_^) ).

Two Fed economists tried to replicate some top economic studies — and the results are dreadful – from mike bird.

The shifting tide of American immigration – from colin woodard.

Missing piece of Gilgamesh Epic discovered

Pompeii Victims’ Bodies Revealed in [ct] Scans: Photos

Excavations at Mexican ruin site yields new details of Aztecs’ sacrifice of captured Spaniards“It was one of the worst defeats in one of history’s most dramatic conquests: Only a year after Hernan Cortes landed in Mexico, hundreds of people in a Spanish-led convey were captured, sacrificed and apparently eaten.”

bonus: Most worker ants are slackers“[N]ew research shows that many ants in a colony seem to specialize in doing nothing at all. To get a closer look at how these ants filled their time, researchers marked every member of five lab-based colonies with dots of colored paint. Over the course of 2 weeks, a high-definition camera recorded 5-minute segments of the ants in action six times a day, capturing their behavior (or lack thereof). Out of the ‘workers,’ 71.9% were inactive at least half the time, and 25.1% were never seen working. A small fraction of the ants, just 2.6%, were always active during observation, the researchers wrote last month in Behavioral Ecology and Sociobiology.”

bonus bonus: How to Dupe a Dung Beetle“A case of biological mimicry has been spotted in Ceratocaryum argenteum, a South African plant that tricks dung beetles into spreading its stinky seeds.”

bonus bonus bonus: Elephants: Large, Long-Living and Less Prone to Cancer“Dr. Schiffman and his colleagues found that elephants have evolved new copies of the p53 gene [“a gene that is crucial for preventing cancer”]. While humans have only one pair of p53 genes, the scientists identified 20 pairs in elephants.”

bonus bonus bonus bonus: DNA Sequenced for New Zealand’s First Dog – the kurī. woof!

bonus bonus bonus bonus bonus: Watch Drones Drop Thousands of Moths on Crops

bonus bonus bonus bonus bonus bonus: Honour, community and hierarchy in the feasts of the archery and crossbow guilds of Bruges, 1445–81

and the tweet of the week… (~_^)

(note: comments do not require an email. “Humans come then go, that is the way fate decreed on the Tablets of Destiny.”)