inclusive fitness

there’s some amount of confusion out there in the hbd-o-sphere (and beyond!) about inclusive fitness, which is understandable since the concept is not that straightforward — especially for those of us who are not scientists. i thought it’d try to dispel some of that misunderstanding by sharing my layman’s understanding of the concept — i think i grok the idea pretty well now (in a basic sorta way) — hope i don’t add to the confusion!

to start with, inclusive fitness is NOT some sort of biological law that organisms (including humans) will automatically be altruistic towards other individuals with whom they share a lot of genes (or vice versa if vice versa). if you hold that idea — and i get the impression that a lot of people do — get it out of your mind right now! you’ll feel better for it, trust me.

inclusive fitness is simply a concept or model which explains HOW certain social behaviors — especially altruism — might’ve evolved at all. period. full stop.

to understand inclusive fitness, we need to back up a sec first and think about fitness and what that is. very (very!) simply, fitness refers to an organism’s ability to survive and reproduce in a particular environment. traits — including behaviors — that enable an organism to survive and successfully reproduce will be selected for simply because that organism *is* able to survive and reproduce in its environment. this is natural selection. pretty simple, really, darwin’s dangerous idea.

when it comes to certain social behaviors in humans, it’s readily understandable why many of them were selected for. for example, mothers who devote a lot of time and energy to care for their infants — who obviously can’t take care of themselves and would die without any care — will be more fit than those mothers who don’t. the genes that predispose for those behaviors get selected for since children get half of their dna from their mothers, and the ones that are cared for are much more likely to survive.

what was — and to some extent still is — a big mystery is why other sorts of altruistic behaviors were ever selected for even though they hurt an organism’s fitness. how would self-sacrificing altruistic behaviors directed towards non-descendants ever be selected for? for instance, why on earth would somebody feel compelled to run into a burning building to save a neighbor (who wasn’t their child) at great risk to their survival and, therefore, to their fitness? we can see how “genes for altruistic behaviors towards offspring” could be passed down from mother (or parents) to kids, but how were genes for more general altruistic behaviors selected for?

here is where william hamilton‘s absolutely genius idea — inclusive fitness — comes in: perhaps certain social behaviors, which on the surface appear to reduce an organism’s fitness, and so shouldn’t get selected, might’ve been selected for if those behaviors were directed toward other close kin with whom individuals also share much dna in common.

everybody gets half of their dna from each of their two (for now, anyway) parents. but we also share dna with siblings and (blood-related) aunts and uncles and (wait for it…) cousins. given this inheritance pattern, probability says, for instance, that, in a randomly mating population, an individual should share 12.5% of their dna with a first cousin. so, if an individual with certain “genes for altruism” behaves altruistically toward their first cousins, odds are not bad that those first cousins might also have those same “genes for altruism.” here, then, we have a mechanism for how apparently self-sacrificing social behaviors can be selected for: since the altruistic individual 1) aids close kin with whom he shares much of his dna AND 2) probably in many instances shares the same “genes for altruism,” his being altruistic toward those kin 1) does not reduce his fitness AND 2) the “genes for altruism” get selected for, too. mystery solved. (see also: kin selection.)

one way i like to think of inclusive fitness — which, perhaps, isn’t entirely the right way to look at it, but i feel it helps my understanding — is that if you wanted to calculate an individual’s total fitness by adding up how many actual copies of his genes he passed on, you need to add together those found in his offspring and those in his close relatives’ offspring. in other words, you need to add together his own direct fitness plus his close relatives’ fitness to get his inclusive fitness (or his total fitness).

it seems likely that many of the altruistic (or spiteful, etc.) behaviors we’re talking about are pretty general in nature, i.e. not that specific behaviors like “be altruistic to your close kin” were selected for, but rather more like “be altruistic to the people around you, because they’re probably your close kin” were. it remains to be seen how much kin recognition plays a role in altruism in humans, but that’s a topic for another post anyway. for right now, i just wanted to make clear what inclusive fitness is — and isn’t. again, inclusive fitness is a concept which explains HOW altruistic behaviors MIGHT be selected for. it does NOT predict that individuals will DEFINITELY be more altruistic toward those with whom they share much dna.

the whole topic of inclusive fitness is, of course, much more complicated than all that, but i think this is a good basic intro to the concept. hope so, anyway! (^_^)

(note: comments do not require an email. citizens against altruism!)

Advertisements

linkfest – 08/17/14

I can’t afford to think about that“[W]hy are balls of steel so rare in academia? Do they undergo a procedure?” – from greg cochran.

Species Do Not Exist“[T]he Endangered Species Act has shaky conceptual foundations…. And yet we somehow deal with the fact that the universe is complex when it comes to species, although not with races.” – from steve sailer. see also Should You Fear the Pizzly Bear? h/t werner jensen!

Catastrophes in evolution: Is Cuvier’s world extinct or extant?

Million year hominid dispersal event in Iberia“Archaeological remains dating to between 1 million to 780,000 years were also found on an excavation that has provided evidence of the first known human occupation in the Iberian Peninsula.” – h/t cultevobot!

Early Exit: When Did Modern Humans First Leave Africa?“[A] recent study in Proceedings of the National Academy of Sciences of the genes of indigenous people in southeast Asia has suggested a much earlier date for the first human explorers. Professor Katerina Harvati-Papatheodorou and lead author Hugo Reyes-Centeno of the University of Tubingen in Germany and their colleagues fed this genetic data into a computer model of migration and found that the best explanation was an African exodus around 130,000 years ago, more than twice as far back as most scientists think. They also suggested that this early wave took a different route, spreading along the south coasts of Arabia and Asia towards Australia.”

Early modern humans were ‘culturally diverse’ before they left Africa“Researchers have carried out the biggest ever comparative study of stone tools dating to between 130,000 and 75,000 years ago found in the region between sub-Saharan Africa and Eurasia. They have discovered there are marked differences in the way stone tools were made, reflecting a diversity of cultural traditions. The study has also identified at least four distinct populations, each relatively isolated from each other with their own different cultural characteristics.”

Indo-Europeans preceded Finno-Ugrians in Finland and Estonia“An archaic (Northwest-)Indo-European language and a subsequently extinct Paleo-European language were likely spoken in what is now called Finland and Estonia, when the linguistic ancestors of the Finns and the Sami arrived in the eastern and northern Baltic Sea region from the Volga-Kama region probably at the beginning of the Bronze Age.” – @dienekes’.

168 South Asian Genomes – @dienekes’.

Claim: Modern human teeth in southern China 70-125 ka BP – h/t razib!

The Most Violent Era In America Was Before Europeans Arrived“[A] new paper finds that the 20th century, with its hundreds of millions dead in wars and, in the case of Germany, China, Russia and other dictatorships, genocide, was not the most violent – on a per-capita basis that honor may belong to the central Mesa Verde of southwest Colorado and the Pueblo Indians. Writing in the journal American Antiquity, Washington State University archaeologist Tim Kohler and colleagues document how nearly 90 percent of human remains from that period had trauma from blows to either their heads or parts of their arms. ‘If we’re identifying that much trauma, many were dying a violent death,’ said Kohler. The study also offers new clues to the mysterious depopulation of the northern Southwest, from a population of about 40,000 people in the mid-1200s to 0 in 30 years.” – h/t hbd bibliography!

The ‘six universal’ facial expressions are not universal, cross-cultural study shows“It’s a con­cept that had become uni­ver­sally under­stood: humans expe­ri­ence six basic emotions — happiness, sad­ness, anger, fear, dis­gust, and surprise — and use the same set of facial move­ments to express them…. The only problem with this con­cept, according to North­eastern Uni­ver­sity Dis­tin­guished Pro­fessor of Psy­chology Lisa Feldman Bar­rett, is that it isn’t true at all…. [W]hat were assumed to be ‘psy­cho­log­ical uni­ver­sals’ may in fact be ‘Western’ — or per­haps even ‘American’ — cultural cat­e­gories.”

The intelligent pursuit of happiness“Intelligence is associated with health and longevity, and more intelligent children on average tend to live longer and healthier lives than less intelligent children, although it is not known why. Health is significantly associated with psychological well-being. So, it is possible that more intelligent individuals are more stable in their happiness over time because they are more likely to remain constantly healthy than less intelligent individuals.” – from dr. james thompson.

Clues emerge to genetic architecture of intelligence in children“‘When we computed the contribution of common variants to these cognitive abilities, we found that some of the contributions were substantial,’ said Hakonarson. For instance, common SNPs accounted for roughly 40 percent of the population differences in nonverbal reasoning, and 30 percent of the differences in language reasoning, with the balance of the differences attributable to rare variants and environmental factors. On the other hand, common gene variants together contributed to only 3 percent of the differences in spatial memory—the ability to navigate in a geographical location. There also were significant overlaps between trait domains. Reading ability, which was 43 percent attributable to common variants, was often inherited together with language reasoning abilities.” – h/t nolasco!

Lead released from African cookware contaminates food“Researchers tested 29 samples of aluminum cookware made in Cameroon and found almost all had considerable lead content. This cookware is common throughout Africa and Asia and is made from recycled scrap metal including auto and computer parts, cans, and other industrial debris. Lead exposure in children is linked to brain damage, mental retardation, lower educational performance, and a range of other health effects.” – h/t science enabled!

Facial fluctuating asymmetry is not associated with childhood ill-health in a large British cohort study – h/t jelte wicherts! who tweeted: “Contrary to several small N studies, large study finds no relationship between health measures & facial asymmetry.”

Structural Growth Trajectories and Rates of Change in the First 3 Months of Infant Brain Development – h/t simon baron-cohen! who tweeted: “Typical brain growth from birth to 3 months old: the brain grows 1% per day, and male brains grow faster.”

Workaholism: The addiction of this century“Workaholics scored higher on three personality traits: Agreeableness, Neuroticism, Intellect/Imagination.” – h/t claire lehmann!

Twins separated at birth reveal staggering influence of genetics“Segal, who wrote a book about the study called ‘Born Together Reared Apart: The Landmark Minnesota Twins Study’ (Harvard University Press, 2012), is now doing a prospective study of Chinese twins raised apart, often in different countries, by adoptive families.”

The association between grandparenthood and mortality – h/t neuroskeptic! who tweeted: “People who become grandparents at an early age tend to die sooner.” – because they have faster life histories?

Getting the babes but not the babies“Who’s making more babies? ‘Good boys’ or ‘bad boys’? Originally, the good boys were, thanks to parental monitoring of relations between single men and single women. The pendulum then swung toward the bad boys in the 1940s, only to swing back after the 1960s.” – from peter frost.

Population-level variability in the social climates of four chimpanzee societies – h/t erwin schmidt! who tweeted: “Some groups of chimpanzees are more egalitarian than others.”

Is empathy in humans and apes actually different? ‘Yawn contagion’ effect studied“Humans and bonobos are the only two species in which it has been demonstrated that yawn contagion follows an empathic trend, being more frequent between individuals who share a strong emotional bond, such as friends, kin, and mates…. Two features of yawn contagion were compared: how many times the individuals responded to others’ yawns and how quickly. Intriguingly, when the yawner and the responder were not friends or kin, bonobos responded to others’ yawns just as frequently and promptly as humans did. This means that the assumption that emotional contagion is more prominent in humans than in other species is not necessarily the case. However, humans did respond more frequently and more promptly than bonobos when friends and kin were involved, probably because strong relationships between humans are built upon complex and sophisticated emotional foundations linked to cognition, memory, and memories. In this case, the positive feedback linking emotional affinity and the mirroring process seems to spin faster in humans than in bonobos. In humans, such over-activation may explain the potentiated yawning response and also other kinds of unconscious mimicry response, such as happy, pained, or angry facial expressions.”

Self-regulatory failure and the perpetration of adolescent dating violence: Examining an alcohol use by gene explanation“[A]lcohol use was more strongly associated with dating violence among adolescents who had a high rather than a low multilocus genetic profile composed of five genetic markers that influence dopamine signaling. Alcohol use was more strongly related to dating violence among boys with long rather than short 5-HTTLPR alleles, the opposite of the prediction. MAOA-uVNTR did not interact with alcohol, but it had a main effect on dating violence by boys in later grades in the expected direction: boys with more low activity alleles perpetrated more dating violence. Exploratory analyses found variation in findings by race.” – h/t unsilenced science!

Take Two Sugar Pills and Call Me in the Morning“Over the past decade, a number of clinical studies have begun to show that people who improve on placebos are genetically different than those who don’t.” – h/t billare! see also here.

Designer babies: selection vs editing – @steve hsu’s.

Anxiety in invertebrates opens research avenues“[N]euronal mechanisms related to anxiety have been preserved throughout evolution. This analysis of ancestral behavior in a simple animal model opens up new avenues for studying the neuronal bases for this emotion.”

Our Microbiome May Be Looking Out for Itself – sneaky microbiome! h/t mr. robert ford!

New Study To Look At The Genetics Of Inflammatory Bowel Disease – from 23andMe.

Constitutional verbosity and social trust – h/t heartiste! who tweeted: “The more a nation’s people trust each other, the fewer words they need to codify that trust.”

War in the womb“A ferocious biological struggle between mother and baby belies any sentimental ideas we might have about pregnancy” -h/t charles!

Head Count – ‘Malthus,’ by Robert J. Mayhew

New Saudi ban on marriage to foreigners stirs controversy“[A] new law bans Saudi men from marrying women from Pakistan, Bangladesh, Chad and Burma.” (not a big surprise from the najdis.)

Avoid marrying kin, behave ‘softly on first night’“A notice from the Health Ministry [of turkey-h.chick] on ‘Consultancy before Marriage’ has highlighted that one out of every five marriages are among kin. The recently released document also includes sexual advice for couples, especially for the ‘first night.’ ‘Consanguineous marriage is mostly among first-degree relatives, increasing the number of rare genetic diseases,’ it said. ‘This matter is noteworthy. Those who are married to kin and those who carry genetic diseases should consult a health institution before gestation.'” – h/t anatoly karlin!

Avoiding Prince Joffrey: Primates have newly discovered ability that stops inbreeding“[N]ew research in macaques has revealed for the first time that primates are able to recognise their own relatives. The researchers opted for macaques rather than chimps for their study as the former lives in larger groups with more relatives; allowing them to pick distantly related monkeys who haven’t met, they could rule out ‘familiarity’ as a way for figuring out who is related…. The researchers had no clue as to how they were able to do this. Perhaps they did make a ‘template’ based on relatives they were familiar with, or maybe they had figured out what they looked like somehow, so could use that to figure out who were their relatives.”

Download Pew Datasets!

bonus: Researchers create 1,000-robot swarm – PANIC!!1! HEAD FOR THE HILLS!!

bonus bonus: The Domestic Cat Genome Has Been Fully Sequenced, and It’s Fascinating“Cats also have what biologists call “a highly conserved ancestral mammal genome organization,” which means that many stretches of their genome haven’t changed much over evolutionary time. Put simply, domestic cats haven’t changed much since they first evolved.”

bonus bonus bonus: Reconstructions show how some of the earliest animals lived — and died – rangeomorphs. h/t mike anissimov!

bonus bonus bonus bonus: Shortest-known abstract for a serious scientific paper (^_^)

(note: comments do not require an email. happy capybara!)

recognizing your un-kin

if you want to be un-altruistic toward some un-kin of yours, it might be useful if you could spot who they are.

here’s some neat research [pdf] suggesting that perhaps we can do just that (further research is required, of course). this is one of those manipulated photographs studies — you know — where they take photos and alter them to look more or less like the subjects. note that the study was done on w.e.i.r.d. students — and way more females (n=112) than males (n=32):

“Kin recognition: evidence that humans can perceive both positive and negative relatedness” (2012)

“… The evolution of spite would have been greatly facilitated by the ability to recognize negative relatives (West & Gardner, 2010). The current study is the first to find such an ability among humans, one of only a handful of species (Keller & Ross, 1998; Giron & Strand, 2004) for which there is evidence of negative relatedness recognition, by introducing a novel cue to negative relatedness (negative self-resemblance). Specifically, we found opposing effects of positive and negative self-resemblance – cues to positive and negative relatedness, respectively – on trusting and attractiveness attributions, as predicted. This result provides a foothold for the possibility of the evolution of spiteful behaviour among humans. Future research should examine this possibility.

“Although the effects of positive and negative self resemblance in our study were generally small, our study was an experimental one. Thus, we controlled the strength of the manipulation. It was our intention to make the stimuli subtle, to ensure that the participants would not discover the nature of the manipulation. A subtle manipulation, however, will tend to lead to subtle effects. What we hoped to show was not that the positive and negative self-resemblance manipulations had large effects on preferences or behaviour in the context of a laboratory experiment, but that they had predictable effects at all, especially as these effects speak to theory (Prentice & Miller, 1992).

Relative to matched participants, focal participants generally had positive preferences for their own positive self-resembling faces but negative preferences for their own negative self-resembling faces across contexts….

here’s the relevant graphic:

negative relatives

Spite is hypothesized to evolve under relatively restrictive conditions (West & Gardner, 2010), and so it is expected to be rare. However, two conditions may, together, favour its evolution: (1) ‘viscous’ breeding systems and (2) the ability to recognize negative relatives. Population viscosity can make competition increasingly local among individuals (Taylor, 1992a,b), and local competition encourages the evolution of spite (Gardner & West, 2004). Furthermore, individuals immigrating into a viscous population may be strongly negatively related to members of the indigenous population, because immigrants are highly unlikely to bear the same (relevant) alleles as indigenous individuals (Krupp et al., 2011).”

for “viscous breeding systems” i think we can safely insert “inbreeding” or “cousin marriage” or “consanguineous matings.” they are all certainly viscous.

“Negative relatedness recognition can improve the targeting of a spiteful action to increase indirect fitness benefits (by delivering harm specifically to negative relatives whilst sparing positive ones), and our results provide evidence that humans have the mechanisms in place to do precisely this. Moreover, countless animal species use phenotype matching to determine relatedness, and other kin recognition systems exist that might also be employed to discriminate against negative relatives (reviewed in Krupp et al., 2011). Further discoveries that organisms have the capacity to recognize negative relatives will lay a foundation for the study of spiteful behaviour, arguably the last great unexplored problem of social evolution….”
_____

what i’d like to see is some research done on actual inbred populations. maybe a comparison between a non-inbreeding population and an inbreeding one to see if either of the two groups is better at spotting their kin or un-kin.

for that matter, i wonder if kin in inbred populations actually look more like one another than kin in outbred populations (and, therefore, look more unlike non-kin). you would think they ought to since they share more of the same genes with one another. you’d think that’d affect appearance, too. remember the ghoul brothers from syria (click on picture for LARGER view)?:

ghoul brothers

redzengenoist said about them: “It really is striking how much they look like one another. Far more than I would expect the average family group to have similar appearance…. I’m thinking of selection for markedness of ingroup-ness. I can’t help but wonder if having a distinct ‘look’ helps to facilitate the evolutionary advantages of inbreeding….”

i noted: “and, like the big families i’ve known (from my slightly inbred area of the world), some of them look more like each other than they do to the others. the two (chubby guys, roundish faces) on the right and the guy all the way on the left look similar — those three look like mom? or dad? and the other five look more like each other — like the other parent (whichever one).”

maybe it’s easier to spot kin and non-kin in a “viscous” population. the more viscous the better, perhaps.

(note: comments do not require an email. play spot the relatives!)

kin recognition

greg cochran said: “[Y]our comment implicitly assumes that people somehow _know_ just closely related family members, and of course they don’t.”

i think he meant that kin recognition isn’t something innate in humans, although maybe i’ve misunderstood what he wrote (wasn’t completely clear to me). i disagree. i think there is good evidence that people do somehow “know” their relatives. it’s not a perfect system, but it does exist.

first, a little anecdotal evidence (which obviously isn’t scientific evidence in any way):

nearly everytime i go back to the “old country,” some stranger that i’ve never seen before in my life is sure to stop me in the street or in a cafe and say: “you must be one of the so-and-so’s.” this, you understand, happens in or near the town where my family is from — not at the other end of the country, of course (although come to think of it, i actually have another anecdote related to that which i’ll tell you below). two interesting examples of this come to mind. on one occasion, a very old man stopped and asked me if i was one of the “so-and-so’s” and he was referring to my maternal grandmother’s side of the family. because i’m pretty aware of my family history, i was able to confirm that i was, indeed, one of the “so-and-so’s.” he was quite old and he claimed that i looked just like my great-grandmother who he remembered from when he was a boy. the second example was a guy who told me i reminded him of his sister in both appearance and mannerisms, so we sat down and tried to figure out who each other was, and we eventually worked out that we were, in fact, second-cousins.

i said that this usually happens to me when i’m in the area where my family comes from in the “old country,” but here’s another example: one of my cousins, who like me did not grow up back where our parents came from, was on vacation in another country when a stranger she had never met before asked her if she was one of the so-and-so’s. this stranger was from the area where my and my cousin’s family came from, and he recognized her as one of us. (^_^)

(this sort of stuff that i’ve experienced my whole life is why this did not surprise me at all.)

so, people in traditional societies are attuned to appearance and personality in other individuals and they use them to identify relatedness (is this person a member of my family or of another family? if another family, which other family?). i’m sure their success rate is nothing like 100%, but they seem to me to be pretty good at it.

i think most americans are unaware that this sort of thing goes on in other societies simply most americans don’t do this. and that’s because the population in large parts of the u.s. is so jumbled up. why would you look for family resemblances in order to identify people in a place like new york or los angeles? pretty pointless. maybe it happens in areas of the country that have been settled the longest and haven’t experienced many changes in their populations. dunno.

but those are just a couple of anecdotes. now for some scientific studies:

– one of my faves: Grandma plays favourites: X-chromosome relatedness and sex-specific childhood mortality (posted about here). because of the differential inheritance of the x- and y-chromosomes, grandparents are not related to each of their grandchildren equally — and this seems to show up in the amount of time/resources a grandmother invests in each of her grandchildren. the more dna grandma shares with you, the more she’s going to invest in you. and vice versa. you’d think this must be some sort of innate behavior, ’cause i don’t imagine grandmas in nonliterate societies go around calculating the genetic relatedness between themselves and their grandkids.

The neuronal substrates of human olfactory based kin recognition — smell tests showing that women can identify their sisters vs. their female friends via odor.

The sibling uncertainty hypothesis: Facial resemblance as a sibling recognition cue“Within families, individuals reported greater closeness and altruism toward siblings who more closely resembled them.”

Kin recognition: evidence that humans can perceive both positive and negative relatedness“Participants made trustworthiness and attractiveness judgements of pairs of opposite-sex positive and negative self-resembling faces. Analyses revealed opposing effects of positive and negative self-resembling faces on trustworthiness and attractiveness judgements.”

– and from the chapter entitled ‘Cooperation, Conflict, and Kin Recognition’ in The Oxford Handbook of Evolutionary Family Psychology:

“[T]echnological innovations now make it possible to experimentally manipulate a postulated label of kinship — facial resemblance — to investigate phenotype matching mechanisms. In these studies, images of participants’ own faces are used to digitally alter the appearance of a set of faces, unfamiliar to the participants, to generate realistic, self-resembling stimuli (Fig. 20.2). Participants’ responses to selfresembling faces, relative to control faces, are then used as indices of cooperative and sexual inclinations toward kin (for a review of the methods and findings, see DeBruine et al., 2008).

“In an experimental task assessing monetary transfers between pairs of individuals, DeBruine (2002) found that participants were more trusting of selfresembling partners than controls. Furthermore, in a test of theoretical predictions that cooperation in ‘tragedy of the commons’ contexts — wherein there is a conflict between individual and collective interests — is enhanced by genetic relatedness, Krupp, DeBruine, and Barclay (2008) found group cooperation (as measured by monetary transfers to the group) increased as a function of the number of self-resembling members of the group.”

there are more studies out there showing that innate kin recognition is something real. there are also those that have found that it does not exist. (you can sift through some of them here on google if you like.) i’m inclined to believe that we can, on average, identify our close relatives (out to first-cousins maybe?) using resemblance clues with pretty good accuracy, but i’m happy to accept that the jury is still out on the matter (more research is required! (~_^) ).

something that greying wanderer has suggested is that maybe inbred peoples are better at this — i.e. have better innate skills to identify family — than outbred peoples. interesting idea. i like it!

(note: comments do not require an email. kin group!)