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!)

linkfest – 07/16/13

not sure if this is a late linkfest from this past sunday or an early linkfest for next sunday…. (~_^)

Patterns of selection on Neanderthal alleles in modern humans“‘We identified Neandertal alleles that are at higher frequency than expected under a model of neutral evolution, and identify dozens of genomic locations in Europeans and East Asians at which the Neandertal alleles are the targets of positive selection. Interestingly, there is evidence for more extensive positive selection in East Asian than in European populations.'” – @race/history/evolution notes.

On the antiquity of language: the reinterpretation of Neandertal linguistic capacities and its consequences“[W]e argue here that recognizably modern language is likely an ancient feature of our genus pre-dating at least the common ancestor of modern humans and Neandertals about half a million years ago.” – via mr. mangan, esq.!

World’s Oldest Calendar Found in Scotland“British archaeologists have found what they say is the world’s oldest calendar, dating back to about 8,000 BC.”

Paternal age and fitness in pre-industrial Finland“‘Individuals whose fathers, grandfathers and great-grandfathers fathered their lineage at age of 20 were ~9% more likely to survive to adulthood than those with 40-year-old male ancestors.'” – @race/history/evolution notes.

Law alone?“People of northwestern European descent put the least emphasis on the blood bond of a nation’s population…. The paradox presented here for many like myself is that the places inspiring the warmest feelings and that I would like most to live in are the places that tend to put the least effort into maintaining what they have. It’s tragic.” – yup. =/ from the awesome epigone.

Ethnic background influences immune response to TB“Over the thousands of years that humans have been infected with TB, people of different ethnicities have evolved different immune mechanisms for handling the bacteria, a finding that could affect the outcome of planned trials for new TB drugs…. [D]ifferences in the way TB affects the body are also linked to ethnicity. For example, he found that most infections in Europeans are in the lungs, for example, while Asians and Africans get most TB infections in other organs.” – @new scientist. also: Scientists discover ethnic differences in immune response to TB bacterium.

Link between low vitamin D blood levels and heart disease varies by race“Low vitamin D blood levels are linked to greater risk of heart disease in whites and Chinese, but not in blacks and Hispanics.”

Early spatial reasoning predicts later creativity and innovation, especially in STEM fields“Exceptional spatial ability at age 13 predicts creative and scholarly achievements over 30 years later, according to results from a new longitudinal study published in Psychological Science.” – via futurepundit! see also steve sailer: Something intelligent and interesting in the news.

Nature, nurture, and expertise“More than half of the difference between expert and normal readers is genetic…. Less than a fifth of the expert-normal difference is due to shared environment.” – via mr. mangan, esq.! see also dr. james thompson.

‘Genes’ a reason poor kids struggle at school, says [an australian] government report“In a controversial new report released today, the Productivity Commission cites ‘parents’ cognitive abilities and inherited genes’ as one of five main reasons why kids from low-income families lag behind those from wealthy homes.” – surely heads must be rolling!

Who’s Having the Babies? – from jayman … who’s having a baby! (~_^)

Brain scans of inmates turn up possible link to risks of reoffending“Those with low ACC [anterior cingulate cortex] activity were about twice as likely to commit crimes within four years of being released as those with high ACC activity.” see also Born to Kill from jared taylor.

Chinese People May Be at Higher Risk for Stroke Than Caucasians“[T]he research found a slightly higher overall risk of stroke in Chinese people than in Caucasians, with a range of 205 to 584 strokes per 100,000 Chinese people age 45 to 74, compared to 170 to 335 strokes per 100,000 Caucasian people the same age. Chinese also had a higher risk of intracerebral hemorrhage, a type of stroke due to bleeding into the brain from a ruptured blood vessel, compared to Caucasian people, or 33 percent of all strokes compared to 12 percent of all strokes in community-based studies. Chinese people had a lower average age of stroke onset of 66 to 70 years-old, compared to 72 to 76 years-old for Caucasians.” – via hbd bibliography!

Study: Even with similar cancer treatment, African Americans don’t live as long as other patients“It’s likely ‘not related to the treatment,’ Ferrajoli speculated, ‘it’s probably a different biology.'” – via amren!

Child food neophobia is heritable, associated with less compliant eating, and moderates familial resemblance for BMI – via jayman!

Poles in the Tent“[I]f high-quality protein were the long pole in the tent, male provisioning of meat, which we see in chimpanzees, might matter quite a bit more than you would think from the number of calories alone.” – from greg cochran.

Dark Counsel From The Durants“‘Inequality is not only natural and inborn, it grows with the complexity of civilization. Hereditary inequalities breed social and artificial inequalities; every invention or discovery is made or seized by the exceptional individual, and makes the strong stronger, the weak relatively weaker, than before.'” – dark stuff, indeed! from malcolm pollack. here’s the durants’ The Lessons of History.

The Death of Enlightenment – or How Nebraska Beats California – from staffan.

‘Big Givers’ Get Punished for Being Nonconformists“People punish generous group members by rejecting them socially — even when the generosity benefits everyone — because the ‘big givers’ are nonconformists.” – you just can’t win with humans!

Genetic diversity, economic development and policy – from jason collins.

Emmanuel Todd’s Theory of Modernity from t.greer.

The other slave trade“Europe used to export slaves to the non-European world.” – from peter frost.

D.N.A. Backs Lore on Pre-Columbian Dogscarolina dogs! — or dixie dingos! woof! (^_^)

Dementia Rate Is Found to Drop Sharply, as Forecast

bonus: make sure to check out elijah armstrong’s new blog!

bonus bonus: Chinese Logographs vs. the Latin Alphabet“[C]ultural systems *do* matter when it comes to cultural advancement and enrichment.” – @habitable worlds.

bonus bonus bonus: Review of “Shots Fired” by Sam Francis – from foseti.

bonus bonus bonus bonus: The rise of identitarian thought… – @occam’s razor.

bonus bonus bonus bonus bonus: Social Truth Vs Objective Truth and Social Truth II and Social Truth III – from the assistant village idiot.

bonus bonus bonus bonus bonus bonus: Dyslexia is Britain’s secret weapon in the spy war: Top codebreakers can crack complex problems because they suffer from the condition

bonus bonus bonus bonus bonus bonus bonus: Isolated Afghans contemplate mass exodus“The 1,100 ethnic Kyrgyz living in this isolated sliver of Afghanistan wedged between Tajikistan, Pakistan and China have been spared the violence that has plagued the rest of their country. But they have also done without the burst of foreign aid that has helped reconstruct one of the world’s poorest nations.”

bonus bonus bonus bonus bonus bonus bonus bonus: A Village Invents a Language All Its Own“The language, called Warlpiri rampaku, or Light Warlpiri, is spoken only by people under 35 in Lajamanu, an isolated village of about 700 people in Australia’s Northern Territory. In all, about 350 people speak the language as their native tongue.”

bonus bonus bonus bonus bonus bonus bonus bonus bonus: Pictured: ‘Vampire’ graves in Poland where skeletons were buried with skulls between their legs – cool!

bonus bonus bonus bonus bonus bonus bonus bonus bonus bonus: Genetic Differences That Let Octopods Flourish – octopod biodiversity!

(note: comments do not require an email. a dixie dingo!)