1
Q
ambisexual/philic
A
bisexuality; attracted to 2 or more genders
2
Q
androphilic
A
attraction to masculinity and men
3
Q
gynephilic
A
attracted to femininity and females
4
Q
asexual
A
no sexual attraction
5
Q
aromantic
A
no romantic attraction
6
Q
cisgender
A
birth sex is consistent with gender identity
7
Q
transgender
A
gender identity or expression not consistent with their presumed sex at birth
8
Q
agender, non binary, and gender-fluid
A
gender terminology does not apply
9
Q
behaviour vs. orientation
A
- there are people whose gender identity/stated sexual orientation is not entirely consistent with the behaviours they engage in
- orientation does not predict reproduction
- sexual orientation (gender) is on a continuum
- range of what people experience, like and label themselves
- attraction does not equal behaviour
10
Q
kinsey scale
A
7-point rating system that describes a person’s sexual orientation, ranging from 0 exclusively heterosexual and 6 exclusively homosexual
11
Q
is sexual orientation learned
A
- important to account for that not everything is a biological difference
- males: no evidence
- females: questionable evidence
12
Q
females and learned sexual orientation
A
- more open to change in preferences as a result of experiences
- set the range of a trait and experiences impact where on that range you end up
- may be more fluid across the lifespan
13
Q
conversion therapy
A
punishment can be effective is stopping behaviours so someone may stop engaging in homosexual behaviours but it doesn’t seem you can actually punish away to attraction or inclination
14
Q
sex reassignment surgery study
A
- john money → sexologist, Harvard, John Hopkins ~60s-70s-80s
- interested in gender expression + sexual orientation
- learning and development view → you can mold/shape the sexual orientation or gender identity of a child if you do the intervention before 2 years old
- thought there was a specific developmental period for gender expression and sexual orientation
- can be cases in routine circumcision resulting in castration → what to do in this case?
- perform surgeries that make them look like girls, raise them as girls, raise them with really strong messages about being a girl, hormone therapy in puberty, and they will be fine
- as long as their bodies look consistent with how parents are raising them to think about themselves and behave, the kids should turn out fine
- this was the standard practice in cases of infant genital surgery, or ambiguous sexual genitalia
- some people were fine with it, but many people struggled → some die by suicide
15
Q
differences in make and female homosexuality
A
- gender identity + sexual orientation shows up fairly early in life
- on average, males self report knowing earlier than females that they are attracted to other males
- more common for their first sexual experience to be same-sex
- blind raters of home-videos: people are pretty good at spotting gay male kids, but very bad at identifying gay female kids
- blind raters, gay males are considered more physically attractive than their siblings - on average, females are more likely to self-report as non-heterosexual later in life
- while gay males tend to know as children, females don’t until later (very big range from adolescence to middle age)
- first sexual experiences more likely to be with males
16
Q
mating strategies with homosexuality
A
- biggest differences tend to be between heterosexual males/females
- regardless of orientation, people tend to be interested in long-term relationships
- if you’re attracted to someone who’s very similar to yourself, there isn’t as much conflict in terms of who wants what
- in the context of long-term relationships, same-sex relationships seem to be much better about having a conversation about dividing responsibilities
17
Q
proximate explanations - family studies
A
- family studies can have potential genetic influences on sexual orientation
- comparisons between fraternal and identical twins
- not 100% concordance in identical, but consistently higher concordance in identical twins than fraternal
- higher concordance in fraternal twins than non-twin siblings → suggests that there might be something in pre-natal exposure?
- concordance rates are higher for males than females → if one sibling is gay, there is a higher likelihood that their male twin will also be gay, than there would be for females
18
Q
proximate explanations - genetics
A
- because the effects are stronger in males than females, some people wondered if it’s a Y linked trait? Or perhaps an X linked trait?
- some evidence for X linked trait, but markers haven’t been identified
- e.g. more gay relatives on your mother’s side than father’s side → typically how the pattern goes.
- most of the evidence we have about genetic influences on sexual orientation are based on gay males
19
Q
hormone exposure
A
biological developmental changes, in utero or early childhood
20
Q
sexual differentiation of the brain - hormones
A
- testosterone exposure in utero → masculinization of the brain (true for both males + females)
- underexposure to testosterone in utero → ~10-12 weeks in male fetus, Y chromosome sends out instructions for body being assembled in stereotypically male ways, if this doesn’t happen, things won’t develop as we’d expect
- excess exposure to testosterone in utero (whether the fetus is male or female) → increased risk for ADD, autism (both of which are associated with stereotypically masculine brain); higher performance on sex-differentiated tasks like orientation, mathematics; gynephilia
- outside of the brain, excess testosterone can result in ambiguous genitalia
- more feminized brain → androphilia; better language skills;
21
Q
cortisol and pregnancy and attraction
A
- chronic stress during pregnancy is associated with an increased rate of same-sex behaviours in offspring (among several species)
- evidence in humans → higher reported rates of same-sex attraction and behaviour in children whose mothers were pregnant during natural disasters
22
Q
typical development of the reproductive system
A
- intersex conditions are a lot more common than we think
- when we start off, we have bi-potential tissue → in the first few weeks of gestation, can’t tell the difference between a chromosomal male or female (at this stage, over- or under-exposure to testosterone can have a big impact on genitalia and brain)
- then, around ~10 weeks, start getting signalling from Y chromosome → leads to suppression of female-typical organs, and upregulates testosterone production → gonads start pumping out testosterone, organizing rest of system
- ~13-14 weeks → starting to develop in stereotypical male or female pattern
23
Q
ultimate explanations of same-sex attraction
A
- is sex attraction, or ambiphilia adaptive? it makes up ~10% of the population, so does that prevalence make it adaptive, good or useful?
- should we instead ask about the adaptive value of heterosexuality?
- what if heterosexuality is not the default, but sexuality? - possible that there’s been selective pressure for males in our species to have a more targeted preference, whereas females have less pressure - maximize our potential if 1 out of 100 of our partners are males, whereas males benefit most from heterosexuality
- fewer bisexual males than females
- female sexuality more facultative → more likely to change across a lifespan
- stronger selective pressure for heterosexuality for males, and weaker selective pressure for women to have exclusive heterosexuality
24
Q
female fecundity hypothesis
A
- fecundity is how likely you are to get pregnant
- fecund = good breeder
- the idea that the more fertile you are, the more likely you will be to be attracted to males
- if these genes show up in relatively high numbers in males, you end up with males with same-sex attraction
- polygenesis → multiple genes contributing to a particular effect/trait, and on average, these genes contribute to high levels of fecundity in females..but if they turn up in males, they’ll be more likely to be gay
25
polygenesis and androphilia
- there are genes associated with androphilia
- females with these genes will be especially attracted to males; have relatively high sex drives for males; higher reproductive output
26
support for the female fecundity hypothesis
- some support for this theory
- female relatives of gay men tend to have more children, on average → could also be support for the next hypothesis
27
reproductive suppression
- we’ll down-regulate number of grandchildren based on what’s happening in our lifetimes
- in a harsh environment there may be reason to limit offspring
28
little brother hypothesis
- the more male fetuses a female body carries → the more antigens she develops against testosterone = greater likelihood of later-born males having feminized traits
- the more older brothers a male has, the greater his likelihood of being gay/not-heterosexuality
29
support for the little brother hypothesis
- don’t see evidence of an older sister effect for females
- may be correlated with more feminized gender expression
- this theory is supported → more older brothers, more likelihood of being gay
30
why is the little brother hypothesis a suppression hypothesis
- competition among males for resources → if you’re going to give birth to lots of males, they’ll compete with each other for lots of things, including access to females.
- the adaptation is that you’re decreasing the amount of competition for your offspring if some of them don’t want female partners
31
cortisol hypothesis
- increase in same sex attraction
- limiting both children and grandchildren. Which reduces their competition for resources
- cortisol secretion during chronic stress → might mean there’s a lot of danger, lack of resources, etc.. not a great environment for bringing offspring into if there’s not enough resources
- suggests that, under times of stress, you up-regulate cortisol in order to down-regulate the reproduction of the next generation → suggests there’ll be more resources for everyone
32
kin selection
- distinct benefit if having non-heterosexual individuals within the population
- overlapping with reproductive suppression
- you can get more of your genes into the next generation if you support the reproduction of those carrying your genes
- inclusive fitness → I don’t have to reproduce directly, in order to have reproductive success. Ultimately, so long as my genes are getting into the next generation, it’s okay if they’re not present in my offspring, but in my nieces and nephews
33
cooperation
- sex is one of the things that tends to reduce stress levels and creates strong bonds between individuals
- if you are having sex with multiple people, they are more likely to share resources and help with offspring, regardless of this person is male or female because there are multiple benefits of having sexual and romantic relationships with multiple people
- because we are a social species that shares, cooperates and collaborates to have better outcomes overall, one of the ways we cement those bonds is through sexual behaviour
34
Fa’afafine of Samoa
- in the manner of a women
- biological men who take on the social roles, mannerisms, and preferred dress of women
- distinct gender unto themselves
- families are generally happy and proud, and start looking for evidence of these tendencies early in life to support their inculturation into perceived gender roles
35
Fa’afatana
- in the manner of a man
- biological females who have behaviours and preferred clothing, ornamentation and social roles typically associated with men ins social culture
- not respected by society and families
- not many admit to it
36
treatment of Fa’afatana and Fa’afafine
- overlap with orientation is complex
- influences of catholicism in terms of how homosexuality is perceived within Samoan culture but they also have a unique interpretation because they see multiple genders
- someone who is seen as a man is considered straight whether they have relations with a woman or Fa’afafine
- Fa’afafine with a woman is not as concerning compared to two fa’afafine
- a fa’afinine is seen as a legitimate partner for a man
37
study on Fa’afinine
- look at kin selection hypothesis → having theoretically non-reproductive members of society is a distinct benefit to the family and potentially society
- looked at difference of spending between men and women and how it compared to Fa’afafine
- married men and women spent it within their family
- single men and women on average spent it on acquiring mates
- Fa’afafine spent money on both themselves (i.e. appearance, just for them to enjoy, books, music, etc), but a disproportionate amount was also invested in their nieces and nephews
38
bonobos
- indiscriminate sexuality
- promiscuous species
- solve a lot of social conflict with physical or sexual touch
- vocalizations and evidence of body movement suggests they engage in touching to the point of organism
- these behaviours are associated with less infant mortality, a gentler society and a more female controlled environment
39
japanese macaques/snow monkeys
- girl on girl mounting
- they often do this behaviour in view of dominant males within the group
- documentation where two females will raise their offspring together
- cooperative behaviours
- males pay attention to girl-on-girl action
- female on female behaviours leads to mounting by a male
- the one being mounted is most likely to be mounted by a male
- same-sex sexual behaviour is leading to heterosexual sexual behaviours
psych 373: evolution & human behaviour
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