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!)