PSY 544 Lecture Notes - Lecture 8: Inclusive Fitness, Grandmother Hypothesis, Weight Gain
• Hypotheses relevant to humans
• Daly et al. (1997)
4. Oe’s positio ithi a eteded ki etork ill e a ore opoet of oe’s
sese of self e.g., I a a daughter/other/sister. We ill thik a lot aout here
we are in a family. Some of the first things that we think of when asked to complete
the sentence I am____ - will be kinship terms: I am a mother/a sister - these will be
psychologically informed to us if kin altruism exists in humans
5. To use Kinship terms will be used to persuade and influence people. Meaning that if
people are naturally more inclined/predisposed to incur a cost on behalf of a kin
then when someone asks you to incur a cost on their behalf, they will try to activate
yoru feelings o f kinship or take advantage of feelings of kinship - this inbuilt thing
that you have that predisposes you to be nicer to your relatives - and you can see
this in a number of different examples where kinship terms might be used by
someone who wants you to help them out so the famous phrase " brother can you
spare a dime" someone is asking you for money and they use this kinship term in
order to try to make you feel more positively towards them. It is notably the case
that we use these kinship terms to try to persuade people to be nice to use then that
supports the idea that we are typically nicer to family than non family. You see it in
other places where it's imp to make bonds b/w people or where for some reason a
group of people/or someone wants to create a bond b/w people use such language
ex. Fraternities and sororities this language in order to try to bond you together - you
are a group of brothers or groups of sisters and maybe it's no coincidence that the
military uses such terminology - band of brothers - when you are trying to get people
to incur a cost on behalf of other people who use kinship terms to activate those
kinship feelings - this again is indirect evidence that there is something imp about
family and you are more inclined to incur costs on behalf of family
• The language of kinship
Evidence for the 1st and 2nd claim: 1st claim about the use of language. Turns out studies
looking at human languages cross culturally do seem to show that there is what's called
the universal grammar of kinship terms, in other words when people produce terms that
distinguish family from the non-family, they do indeed define that most things are made
based on things like groups which would be for ex: same sex vs opp sex siblings, or same
sex vs opp sex parents, this is commonly reflected in words used to describe a kin. Social
ranks ex age which reflects generation - so this person is a generation above/or below me
and this distance: is this person my immediate family or extended family. But there isn't
the same use of every single term in every single language so languages do have slight
variations. In other words, not every distinction between every level of group, social rank,
or distance is present in every language - so it doesn't strongly confirm in the sense that it
isnt the case that for every separate combination of these things you have a different
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word for ex in English the term aunt for all sorts of different people who vary in their
relationship you so an aunt can be your mothers sister or your fathers sister or could also
be your aunt by marriage so females of the generation above so an aunt could be
someone who is related to you but also someone who is not - so it's not the case that
every single distinction is made but when the distinction is made these are the dimensions
on which they are made: thigs like generation, sex, and genetic relatedness
• Jones (2003)
• There is a uiersal graar of kiship ters. The asi opoets do ideed
include distinctions based on group (e.g., same-sex vs. opposite-sex
siblings/parents), social rank (e.g., age), and distance (e.g., immediate vs. extended
family).
• But, the particulars of who is included under which term varies between languages.
o E.g., Eglish uses aut for our other’s sister, our father’s sister, our
other’s rother’s ife, et.
o So, not all languages make the same distinctions, but these are the categories
on which distinctions are made. The way to think about this is to think about
grammar in the rest of language ex. Every language has nouns and adjectives
but we don't have the same adjectives and nouns some languages have words
that other languages don't never the less nouns and adjectives are part of the
universal grammar - so you can think of it the same way that making
distinctions based on group, social ranking, distance is what all languages do
but not all languages make every distinction in the same way. That said, even
when a distinction is explicitly marked in a language often people are aware of
those distinctions for ex.
• The language of kinship
• In The Yanomamö language there is one word that refers to both brothers and cousins, so
there is no linguistic way of marking the difference b/w your brothers and cousins which
there should be because according to kin altruism you are much closer to your brother
than cousin - your brother avg shares 50% of your genes and cousin only 12.5% so the
language doesn't mark it but if you ask people who is your real abawa they tend to point
towards the brothers - so even though the language doesn't mark the distinction people
still recognizing the difference
• Abawa refers to both brothers and cousins.
• Hoeer, people poit to rothers he asked hih oe is our real aaa?
• There seem to be some evidence that kinship terms are imp to us and it's something that
language always marks out and the kinship terms, if we try to classify them can nearly all
be described by whether they describe someone who is male/female (sex), whether they
describe generation, or whether they describe the genetic relatedness. There's also very
strong evidence that people are nicer in general to their kin than non-kin and it's true also
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in traditional hunter gatherer societies for ex. In Hadza, when a hunter has a large share of
meat, one of the first thing they do is go to the houses of their kin and distribute the meat
to the kin. We see the same thing in indigenous people, when a lot of food comes in
through farming the first thing they do is distribute it to their kin
• So in more traditional/or indigenous communities we see food-sharing where food is
preferentially given to the kin
Helping kin vs. non-kin
• Kinship is a powerful predictor of food-sharing (one form of help) cross-culturally.
• Helping kin vs. non-kin
• Some historical analyses also suggest that kin altruism is beneficial and something that has
caused particular individuals survive more than others, showing that there is essentially
kin altruism throughout our past.
• Having kin in close proximity affects actual survival rates, historically.
• McCullough & Barton (1990) – colonists with more genetic relatives in the Plymouth
Colony were more likely to survive the first winter.
• Analysis that original Europeans who went to North American Plymouth Colony, a lot of
the people died over the first winter there so only 50% of the colonist who originally went
survived the winter but the historical records seem to strongly show that the colonist with
more genetic relatives were more likely to survive - again showing kin altruism so if you
went no or less family you were much more likely to die
• Grayson (1993) – members of the Donner Party with more genetic relatives in the
group were more likely to survive to California. This is another historical analysis:
these were a group of people who during the expansion of the European sentiments
in America took a wagon train from the east to the west as they were trying to get to
California. They ended up being trapped and had to cross a mountain range before
winter started otherwise they would have been trapped in the mountains for the
entire winter and again members who had more genetic relatives in the group were
much more likely to survive - so kin altruism seems to have existed historically as
well
• Helping kin vs. non-kin
• Stewart-Williams (2008)
• 319 undergrad students were asked to respond to the same questions about
someone they considered to be a close friend but also about a sibling
• So one of the questions they asked was:
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Document Summary
Hypotheses relevant to humans, daly et al. (1997, o(cid:374)e"s positio(cid:374) (cid:449)ithi(cid:374) a(cid:374) e(cid:454)te(cid:374)ded ki(cid:374) (cid:374)et(cid:449)ork (cid:449)ill (cid:271)e a (cid:272)ore (cid:272)o(cid:373)po(cid:374)e(cid:374)t of o(cid:374)e"s se(cid:374)se of self (cid:894)e. g. , (cid:862)i a(cid:373) a daughter/(cid:373)other/sister(cid:863)(cid:895). We (cid:449)ill thi(cid:374)k a lot a(cid:271)out (cid:449)here we are in a family. It is notably the case that we use these kinship terms to try to persuade people to be nice to use then that supports the idea that we are typically nicer to family than non family. You see it in other places where it"s imp to make bonds b/w people or where for some reason a group of people/or someone wants to create a bond b/w people use such language ex. Evidence for the 1st and 2nd claim: 1st claim about the use of language. Social ranks ex age which reflects generation - so this person is a generation above/or below me and this distance: is this person my immediate family or extended family.
