5. Direct Benefits of Mate choice Core

Question 1

What did Darwin say about sexual selection

Answer 1

• ‘depends, not on the struggle for existence, but on a struggle between the males for possession of the females; the result is not death of the unsuccessful competitor, but few or no offspring” Darwin 1959

Question 2

what was wrong with Darwin’s original view of sexual selection?

Answer 2

• Darwin’s original view of sexual selection was very sexist and was very much based upon his own perception of the world/ experiences/ outlook.

Question 3

what should we change about Darwin’s statement about sexual selection?

Answer 3

• If we remove males from Darwin’s wording and replace with ‘struggle within one sex for matings with the other’ it is a good premise. It is not a struggle for existence but struggle for offspring which is the critical driver.

Question 4

what are the three ways mating can occur?

Answer 4

1) Indiscriminate random mating
2) non-choosy harem accumulation
3) Choosiness

Question 5

Talk about indiscriminate/ random mating

Answer 5

o Could in theory spend a lot less time by mating indiscriminately where the only energy cost is the time spent physically searching. (finding anyone that you can mate with). When you are spending time and energy on something then you are not on something else there has to be a bonus for the cost.
o Only cost is mate searching.

Question 6

Talk about non-choosy harem accumulation.

Answer 6

o The cost of intra sexual competition can be incredibly high and there is no expenditure of energy for the females involved.
o Only cost= intra sexual competition

Question 7

talk about choosy mating

Answer 7

o Have to find time finding individuals you could mate with, then a selection process/ courting rituals, then if you don’t choose the first individual you have to repeat the process. Every time you reject someone you then spend more time looking for someone else.
o Is far more complex than mating randomly
o +selection cost +additional searching.

Question 8

relation of fruit flies to why humans are choosy

Answer 8

Edward & Chapman (2012) studied flies (drosophila melanogaster)
• Take with a degree of caution on how related to humans.
• They produce a large number of eggs but do engage in choice.
• Either randomly assigned females to mate with or allowed males to choose mates and fount that….“male mate choice increased fitness by an average of 1.59 eggs above the leel of male fitness that would be expected by chance” (1.5x as many eggs)
• Even fruit flies are able to use mate choice mechanisms to enhance their fitness by selecting higher quality/ more compatible mates

so if it works for flies this should in theory be same for humans

Question 9

who argued Paternal investment and what did they argue?

Answer 9

In an average lifespan in a fertile environment females could expect between 5-7 children through lifetime every child is a huge investment in parental output thus given this females ought to be more choosy because there is a far greater time and energy cost.

Question 10

what happens with choosiness in other species compared to humans?

Answer 10

Where you do get choosiness in species we tend to get males doing displaying and females choosing. Humans are different in the sense that we do not have males that make huge displays and plain females.

Question 11

why do humans not really make huge displays?

Answer 11

Where humans are polygynous, we can be very polygynous. But where we are monogamous we are extremely monogamous to the extent where female and male reproduction rates are the same. Reproductive output of male and female is the same and thus the males should be just as choosy as the female. Furthermore, even in the case of the fruit flies that mate all over the place even then being choosy is giving an advantage, so we might expect even polygamous males to be choosy to some extent, rather than acquiring as many females as possible

Question 12

overall why are men choosy and why are females choosy?

Answer 12

So females choosy because of huge time commitment and males choosy because of the same or because of the genetic benefit that arises from being choosy.

Question 13

who is choosing who in humans?

Answer 13

So humans have mutual mate choice where both partners are choosing to some degree, the argument has however been made that males and females looking for different traits

Question 14

how do humans attract/ be attractive?

Answer 14

Males and females pick up locally culturally ascribed cue to being attractive and using it to attract mates

Question 15

What are the two types of benefits that can be gained from mate choice?

Answer 15

Direct and indirect

Question 16

what are the direct benefits of mate choice (very generally)

Answer 16

-increase in own RS/ survival
o You have more children so you are more likely to survive
-mate is better so will provide better

Question 17

what are the indirect benefits of mate choice

Answer 17

o Increase in offspring RS/ survival

o Have more grandchildren and surviving children

Question 18

which is better direct or indirect benefits? IE. which type will we focus more on in mate selections.

Answer 18

Buss and Schmitt (1993) Sexual Strategies theory- would argue that it is completely dependant on what type of relationship you are in and who you are.
o Humans are very flexible on how they mate
o What we look for in a Short term mate is different to what we look for in a long term mate.
o And indeed within this what males and females look for in turn is different.
o Crucuially male and female interests in a long term mate become more aligned in a LT relationship.

Question 19

what are direct benefits? (list of)

Answer 19

• phenotypic benefits
• parental care
• resource holding/ sharing
• fertility and fecundity

Question 20

what are indirect benefits (list of)

Answer 20

• Runaway/ ‘sexy son’
• compatible genes
• good genes

Question 21

Points to cover when talking about resource holding potential

Answer 21

-Emlen & Oring (1977) birds and two ways polygyny can work

in human examples:
-mormons & Kipsigis’ hed size (Borgerhoff & Mulder, 1988, 1990)

• Buss 1990- women attracted to cues of resources
• acquiring +monopolized resources can be turned into greater reproductive success.

Question 22

who outlined two ways polygyny can work in birds and what did they find?

Answer 22

• Emlen & Oring (1977) they looked at birds and they outlined two ways polygyny can work. 1) ‘Resource Defence Polygyny’ where a male bird can get a bit of territory and then keen other males away and then mates with multiple females that come to his territory (e.g. the resource of a fruit tree). The females are attracted to the resource that is the fruit tree as opposed to the male. Does involve female choice.

2) ‘Female Defence Polygyny’ where you might have a resource that is evenly distributed and females are distributed around that resource (e.g. grass) the male can not monopolise the resource so instead gathers a group of females and keeps them away from other males. Doesn’t actually involve any female choice.

Question 23

what human data can be used to show the effects of resource holding potential?

Answer 23

Mormon data as men become higher in status then they can acquire more wife’s higher status tends to have more money. Money and farm is monopolizeable and females are monopolizeable if you kick out other males. So both female defence and resource defence coming into play.

• Kipsigis’ herd size (Borgerhoff, Mulder, 1988, 1990)- the bigger a herd a man has the more wives he is able to accumulate. Need to pay bride price and also be able to support that family so bigger the herd the more women you can buy.

Question 24

what overall can be said about acquiring more monopolised resources?

Answer 24

• Acquiring more monopolised resources can be turned into greater reproductive success through greater mating.

Question 25

What was found about what women looked for? But what are potential issues in this?

Answer 25

• Buss 1989, 1990- thought that Women are attracted to cues of resources and drawn to those traits in the first place. Found that over multiple countries when you give questionnaires women tend to rank resource related traits as more important in a partner than men do. Intelligence, ambition, good financial/ social status this is found with large sample sizes.

but argued they could be overplaying this sex difference- ie. women rank intelligence at 5th most important whilst men rank it 6th. Normally it is a difference of one position and top 4 are exactly the same and in the same order.

1) mutual attraction and love 2) dependable 3) emotional stability and maturity 4) pleasing disposition

Question 26

Evidence that people do behave in a way still to show resources?

Answer 26

Lycett and Dunbar (2000) mobile phones were brick like and not many people so having a mobile phone was a cue to resources and that you had money. If they looked at people at a pub and looked at how many phones were out on tables the male to female ratio predicted the number of phones that men had out on the table. The more men to more women the more competition essentially there is so more need to show resources. These days we wouldn’t expect it to be phones out but maybe extent to showing fancy phones/ apple watch and showing status and resource markers.

Question 27

what has happened recently that may effect RHP?

Answer 27

• Male resource preference? Men are in a better place to acquire resources but whats been happening over last 50 yrs is that women have been able to enter the workplace more and monopolise resources more. If females can monopolise then do males begin to look for resources in a partner too? Pencavel (1998) If look back in 1940s e.g. whether the individual has been to uni or not it doesn’t matter the men are not marrying anyone with more education than them but doesn’t matter whether wives have been to uni or just school. 1960’s far more women going to uni and suddenly find that men who have been to uni are much more likely to marry someone who has been to uni than someone who has just been to high school. Women may be actively selecting partners who have the same level of education as them and males have a pool of women at uni so are more likely to end up with them. Availability of women at own educational level so that becomes more attractive.

Question 28

What do Buss and Schmitt argue in response to issues with their study about what people look for in a partner?

Answer 28

• It isn’t enough to have a partner that is well resourced, that partner must be willing to share their resources with you also. E.g. someone cant be a good hunter and not bring it back to you they need to be both- thus Buss and Schmitt (1993) argue that generosity is a key factor when searching for a LT partner. For so long women had so little influence over the marital money so were entirely dependant on how much the man was giving to them. –> so other factors are seen in line as these are vitally important but what happens post here is what narrows mate selection in terms of RHP for women.

Question 29

What paper clearly supports Evolutionary theory and shows that different cultural settings can result status being seen as different?

Answer 29

Yaffe et al., 2018

men look for youth women look for social dominance

Question 30

what are females when it comes to mate finding?

Answer 30

• Females as ‘limiting factors’- one of the most important things males can do when finding a mate is finding one that can conceive.

Question 31

what do animals do to show they are ready for conception?

Answer 31

Emery and Whiten (2003)- chimp females have big sexual swellings when in eustrus and become more swollen bottoms. The higher quality cycles (those which show clearest hormonal shifts) show the biggest and most red swellings. Shows which females are most fertile at any times.

o Kraak and Bakker (1998) found that male sticklebacks show a preference for bigger females- bigger females lay more eggs. Even simple species show these behavioural preferences for traits that are direct indicators of female fertility.

Question 32

what can indicate fertility in humans?

Answer 32

• oestrogen
• body cues
• youth

Question 33

why is oestrogen a good cue to fertility?

Answer 33

regulates the menstrual cycle is critical for female fertility

mice without oestrogen receptors become infertile (Lubahn et al., 1993)

• Sher & Rahman (2000) looked at women with and without fertility issues and found that essentially the women that were infertile were showing lower levels of oestrogen feedthrough. They gave women estriol and found that in control women more went through their system than in the infertile women suggesting that that was part of the problem in their infertility.

thus.. we should find indicators of oestrogen attractive

Question 34

what have studies shown about facial cues to oestrogen?

Answer 34

• Law Smith et al. (2006) biology students brought in urine samples each week and were tested for oestrogen metabolite. Got faces rated for attractiveness- +levels of oestrogen were rated +attractive and +feminine than those with low levels.

BUT
• Jones et al. 2018- women came in week after week for a few years using 5x as many women as previous study (250 compared to 50). Measured oestrogen and progesterone levels each week from saliva samples. Found no effect of current oestradiol nor progesterone so no within or between women effect going on. Nothing clear in human evolution that would explain this effect. In second study all women removed all makeup before photo. In first they just took out women with makeup which could also remove women who had bad skin/ potentially associated with being on the pill. So the second was a bigger and better controlled sample and effect found in the second wasn’t found in the first.
• So we are not sure about faces.

Question 35

What does a WHR indicate?

Answer 35

. Indicated fertility (little girls are straight and same post menopause). One first thing that changes when become pregnant means that waist disappears

Question 36

what was first argued about WHR? But what were issues with this?

Answer 36

• Singh (1993)- 0.7 waist hip ratio and ‘gynoid’ fat distribution. Essentially argues that a woman with a WHR of 0.7 is probably of the right age and probably is not pregnant currently. Found that in different samples men preferred 0.7 to 0.8/9/10 ect. But didn’t show them 0.6 why?? Came out still with saying that 0.7 was ideal if hed shown 0.6 and they preferred 0.7 to 0.6 there would be a greater claim to this. But study still shows that a narrower waist relative to hips is attractive.

Question 37

What is WHR associated with?

Answer 37

o Fertile phase of life- Bjorklund et al. (1996): WHR increased during the transition from cycling to post-menopause.
o Oestrogen levels (Jasienska et al. 2004) found that those with lower WHR had higher oestradiol levels than those with a high WHR.
o Conception rate (Zaadstra et al. 1993): conception rate across 12 cycles of IVF. Found that higher WHR (less curvy) then the lower chances of getting pregnant during a cycle of IVF.

Question 38

what did others argue WHR was being conflated with?

Answer 38

o Tovee et al. 2001- argued that Singh was conflating BMI and WHR- they’re not becoming curvier but becoming lighter- found that BMI predicted attractiveness. Very clear relationship (completely skinny not attractive skinny = attractive (20BMI) and then further then it drops again. For WHR there wasn’t at all a pattern 0.7 bodies were rated as really attractive and really unattractive if you had a WHR of over 8.5 then not rated as really attractive but having a low WHR isn’t enough to get high attractiveness. Cubic relationship between WHR and BMI 75% of variance in the model explained by BMI and 2% explained by WHR. WHR almost negligible for western women.

o Grillot et al. 2014 WHR doesn’t predict E2 (oestradiol) once BMI controlled.

Question 39

what are some more recent studies suggesting about BMI

Answer 39

o Zaadstra (1993)- Independent Effects on conception?  WRH and BMI there is a sig relationship for attractiveness. Those who are obese have a much lower chance of being pregnant those who are slightly overweight have slight less chance but not huge. When throw all of these in the regression together, WHR remained significant and BMI dropped to a trend and the pattern is the same thus being obese was limiting chances of becoming pregnant so might be independent things going in in some samples.

o Jones et al. 2018- WHR and oestrogen there was a significant correlation which was unrelated to BMI

Question 40

what overall can be said about the importance of WHR

Answer 40

o WHR might be linked to oestrogen and thus might be an indicator of fertility in females only caveat is that WHR itself isn’t always vastly important when males are trying to work out how attractive a woman is and varies to a large degree cross culturally. We’ve got an indicator it just doesn’t seem to be extremely used.

Question 41

what happens in attractiveness as age and why has this been argued to happen/ what supports this?

Answer 41

• as women age they tend to be deemed less attractive compared to men when they age.
• has been argued this is because youth is very important in female fertility and females are the limiting factor.
• Zaadstra et al. (1993) fertility declines with age. Once past 31 up to 37 significant reduction in chances for getting pregnant for women.

Question 42

age and donor eggs to get pregnant

Answer 42

• For mid 20’s-mid 40’s using donor eggs to get pregnant via IVF has roughly the same success rate. If using your own eggs there is a dramatic decrease from around 31 onwards and by 40s chances are really low. Ovum eggs are formed during foetal development, as get older these eggs degrade and are far less likely to be viable. Thus, if you want a fertile female the best way to ensure that is to pick someone in their 20s.

Question 43

Study that supports men like younger partners but what does this assume?

Answer 43

• Men prefer younger partners (Buss, 1989) But Buss assumed men can dominate woman’s entire reproductive career- assumes long term monogamy/ long term pair bonding. Making certain cultural/ reproductive assumptions.

Question 44

what was found about facial and vocal cues?

Answer 44

• Facial &Vocal attractiveness also follows a similar pattern to fertility (Wheatley et al, 2014) using US and Hadza. Women in 20s most attractive.

Question 45

what are men highly averse to in terms of age

Answer 45

• Men are averse to signs of menopause in women:
o Coarse hair
o Grey hair
o Greater facial hair

Question 46

what can be said overall for youth?

Answer 46

• Is preference for ‘youth’…or for pre-menopausal woman. Might be a Slight bias to optimal fertility but is it really about just not looking menopausal? This ties into Zebrowitz and Montepare (2008) idea of overgeneralisation that really what were looking at is not a direct preference for age/ state but an aversion to its opposite and is an avoidance pattern

Question 47

what are phenotypic benefits of mate choice?

Answer 47

• Contagion avoidance- is something that both men and women can directly benefit from we are really averse to things that could possibly make us become ill. An argument has been made that elaborate displays might be in place to show good health.
• We are generally in favour of people who look healthy.

Question 48

Study on health preferences for healthy skin

Answer 48

Jones et al. (2004) attitudes to healthy skin. Took 3cm squares out of photos of peoples faces got them magnified and then got them rated for how healthy they looked. Found peoples whose skin was rated most healthy when looking at whole face their faces were rated as more attractive. So anyone whose skin was smoother, with fewer blemishes, more even skin tone and a bit pinker were rated as more attractive. We like healthy looking skin.

Question 49

who argues and what is the overgeneralisation hypothesis

Answer 49

Zebrowitz and Montepare (2008) looked at extent to which cues are valid indicators of the thought they are meant to imply. But didn’t just look at people in general looked at people in top versus bottom half of the distribution. Measured intelligence and got attraction rating of faces and looked then at perceived intelligence. What we find is whether looking at bottom or top of distribution the more attractive someone is at every stage of life, the more intelligent they are perceived to be so there’s a very clear halo effect of attractiveness, if you look attractive people assume you as more clever. But if you look at actual intelligence and measured facial attractiveness you find that in bottom half of the distribution those who are more intelligent are rated as more attractive but those at top half there is no difference. So essentially if you score very low on intelligence you’re likely to look more unattractive possibly due to some underlying genetic issue but above this there is no difference and the overall link between perceived and measured intelligence is quite weak.

Question 50

what may suggest that we just avoid the worst?

Answer 50

• We are certainly as a culture extremely adverse to signs of menopause (greying, bigger waist)
• And very averse to signs of illness e.g. acne cold sores.
• On flip side- hunting data- people know very best and very worst but not good in middle.
• Is it that we prefer or is it that we are avoiding ill health/ age/ the worst hunters seeing an overflow for a very basic bias against something that can only really be perceived at extremes.

Question 51

what evidence supports that we are adverse to signs of ill health as opposed to attraction?

Answer 51

• Nice evidence for this comes from Park et al (2012) who looked at the relationship between pathogen disgust and attractiveness ratings under the idea that we are attracted to healthy looking people because we want to avoid infection, they hypothesised that people who have high levels of pathogen disgust (people who are particularly sensitive to cues of infection) would show strong preference for attractiveness in others. Split the sample between 8 most and 8 least attractive faces in their set. For the attractive targets there is no difference in ratings of attractiveness for those with high or low pathogen disgust. For the low attractiveness there was a significant different between the ratings of those with low pathogen disgust to those with high pathogen disgust with those with high pathogen disgust rating them significantly less attractive. So what we are seeing is that pathogen disgust is triggering people to be more averse to those at the bottom end of the distribution but its not effecting those at the top, so its not driving them to have a stronger preference for cues of health its driving them to have a stronger aversion to cues of ill health. Suggesting that were seeing an overgeneralization of aversion rather than a direct preference for attraction.

Question 52

in terms of aversion they why may we think celebs are very attractive?

Answer 52

So potentially when we consider why people who are considered in cultures as attractive tend to look like each other. E.g. celebs They all look very healthy, no wrinkles, they’re all rich and well dressed and smart so maybe what’s going on is that they are free of the things we may be more adverse to.