Evolutionary explanations of romantic relationships

Question 1

Natural selection

Answer 1

Natural selection works on the basis that some genes will be selected out and others will spread through the species as they have been inherited due to the advantages to their bearers in surviving.

Question 2

Evolution of natural selection

Answer 2

-The genes that have aided survival will be passed on to our offspring and those that don’t will die out.

Question 3

Sexual selection

Answer 3

The theory of sexual selection claims that reproductive rates, like survival rates, are not random: some will reproduce more than others and the genes that helped them reproduce more will then spread through the species.

Question 4

The EEA in sexual selection

Answer 4

-Our mind is adapted to behaviours we faced in the EEA and so our romantic and sexual relationships will be influenced by this behaviour.

Question 5

Parental investment theory

Answer 5

For genes to spread through a population requires successful survival to mating age, reproduction and survival of offspring. Trivers’ parental investment theory explains sex differences in mating and parenting.

Question 6

Parental certainty

Answer 6

• This favours that in general there is a greater maternal then paternal certainty.
• About 4% of children are believed to not be of the offspring of the man the believe is their father (although is more common among those of a lower soci-economic status and those who are unmarried)
• Over 25% of men who demand a paternity test are not the father

Question 7

Parental investment

Answer 7

• Therefore females invest more because they can have a limited number of offspring and the mother has to make a long time of investment to ensure their survival (pregnancy, then up to 4 years of infant care)
• Males can have many offspring without high levels of investment
• Women are committed to parental investment; men are not
• This affects strategies of getting genes into subsequent generations.

Question 8

Men compete

Answer 8

-Therefore men will put more investment into mating to ensure their genes get into subsequent generations. So men compete for sexual access as this increases their reproductive success.

Question 9

Women choose

Answer 9

-Whereas women put more investment into parenting to ensure survival of their offspring. So women choose between competing men as their reproductive success is increased by selecting a suitable male with good genes.

Question 10

Hypothesis 1: men will be more concerned with the physical attractiveness of females than females are with the physical attractiveness of males

Answer 10

Women’s reproductive window is a lot narrower than that of men, i.e., their fertility decreases more steeply than men’s over time. In women, relative youth is thus an indicator of fertility and attractiveness is a rough indicator of both youth and health.

Question 11

Hypothesis 2: women will be more concerned with the resources that males can offer than males are with the resources that females can offer

Answer 11

In the EEA a high proportion of infants would not have survived. Resources, e.g., food and protection from predators, would have been vital for a woman aiming to keep a child alive. As a result a preference for men of high status with access to resources would have evolved.

Question 12

Hypothesis 3: women will be choosier than males in short- term sexual liaisons

Answer 12

The risks of pregnancy in the EEA were high, so women who were less choosy would have often found themselves without a partner or with a less reliable partner. It would have paid for them and their offspring’s survival to be choosy about who to mate with, especially as there was no reliable contraception. Men, on the other hand, could impregnate many women simultaneously, so being too choosy could reduce their reproductive chances

Question 13

Overview of evidence for Hypothesis 1

Answer 13

• Buss’ (1989) ’37 cultures’ study
• Dunbar & Waynforth’s (1995) content analyses of personal ads
• Feingold’s (1990) meta- analysis

Question 14

Overview of evidence for Hypothesis 2

Answer 14

• Buss’ (1989) ’37 cultures’ study
• Dunbar & Waynforth’s (1995) content analyses of personal ads
• Feingold’s (1992) meta- analysis

Question 15

Overview of evidence for Hypothesis 3

Answer 15

-Clark & Hatfield’s (1989) field experiment
Clark & Hatfield’s adaptation (1990) of the same experiment
-Guegen’s (2011) replication of Clark & Hatfield’s experiment
-Buss & Schmitt’s (1993) survey

Question 16

Buss (1989)

Answer 16

• Investigated the priorities of males and females in choosing a partner
• More than 10,000 pps in 37 cultures on six continents and five islands
• Results: men were more likely to choose youth and good looks, whereas women chose good financial prospects, ambition, older age and emotional security.
• Conclusion: Priorities for males and females differ and appear to be universal

Question 17

Dunbar + Waynforth

Answer 17

-Carried out a study using 900 personal adverts taken from north American newspapers
-They found that a younger partner was important for just under half of men 42% compared to a quarter of women.
-Physical attractiveness was sought by 44% of men compared of 22% of women
They also found that men included indications of wealth 1.7 times more than women, and women included demand for wealth in a partner 4.5 times more than men.

Question 18

Buss evaluation

Answer 18

• The main strength is that the study is cross-cultural with a very large sample
• Suggests results are universal and therefore part of human nature, therefore genetic and therefore evolutionary
• Good population validity, the pps aren’t just from western cultures

Question 19

Dunbar & Waynforth Evaluation

Answer 19

• It was a natural occurring experiment they took adverts form local newspapers,
• good ecological validity; real dating situation
• Covert study- unaware they’re in a study so no demand characteristics of social effects
• However the study was only US samples so culture bound results
• Lacks temporal validity limited amount of people used dating sites back then

Question 20

Hypothesis 1: men will be more concerned with the physical attractiveness of females than females are with the physical attractiveness of males (study- Feingold, Alan 1990)

Answer 20

• Evolutionary and sociocultural theories of mate selection preferences; men place greater value on physical attractiveness than do women.
• meta-analyses were conducted of findings from 5 research paradigms: (1) questionnaire studies, (2) analyses of lonely hearts advertisements, (3) studies that correlate attractiveness with opposite sex popularity, (4) studies that correlate attractiveness with liking by a dyadic interaction partner, and (5) experiments that manipulate the attractiveness and similarity of an opposite sex stranger.
• The anticipated sex difference emerged in all 5 meta-analyses, although it was larger in research that examined self-reports than in research that examined social behaviour.

Question 21

Hypothesis 2: women will be more concerned with the resources that males can offer than males are with the resources that females can offer (study- Feingold, Alan 1992)

Answer 21

• Evolutionary-related hypotheses about gender differences in mate selection preferences; derived from R. Trivers’ parental investment model- women are more likely than men to seek a mate who possesses nonphysical characteristics that maximize the survival or reproductive
• examined in a meta-analysis of mate selection research (questionnaire studies, analyses of personal advertisements).
• They found that women cared more than men about socioeconomic status (SES), ambitiousness, character, and intelligence, and the largest gender differences were observed for cues to resource acquisition (status, ambition). -Where valid comparisons could be made, the findings were generally invariant across generations, cultures, and research paradigms.

Question 22

Strengths of Feingold’s studies

Answer 22

• He used meta-analysis which use a variety of studies accounting fro different factors.
• This combines the results from a series of studies therefore likely to identify the general trend in research
• Replication + triangulation; 5 research paradigms, so different types of research.

Question 23

What from Feingold’s 1990’s study weakens support for sexual selection theory?

Answer 23

• The results for self-reports and examined social behaviour were different, therefor people may have different ideas about partners compares to how they actually chose partners in reality
• ‘Ideal partner’ - unrealistic

Question 24

Additional strength to Feingold’s 1992 study?

Answer 24

-The findings were invariant across generations and cultures which increases population validity.

Question 25

Clark & Hatfield (1989)

Answer 25

-They had attractive confederated approach opposite-sex strangers on a university campus and asked either
1- would you go out with me tonight
2-would you come over to my apartment tonight?
3-would you go to bed with me tonight?
-50% of women and men said yes to the first question,
6% of women and 69% of men said yes to the second question and of the 96 students no woman agreed to have sex, but 75% of men did.
-Appears to demonstrate females are more choosy than men when it comes to sex. It had been suggested that it was due to women’s fear for their safety, however these fears were not expressed in debriefing interviews.

Question 26

Clark & Hatfields (1990)

Answer 26

• They modified the experiment in 1990 and assured participants about the trustworthiness of the stranger, the results were still the same- women did not generally agree to casual sex.
• The general unwillingness to engage in uncommitted sex is also found in lesbians (Buss & Schmitt 1993)

Question 27

Buss & Schmitt (1993)

Answer 27

-They asked how many sexual partners people would ideally like over the next two years, the decade and their life time
Next two years: men= 8, women=1
Over a lifetime: men= 18, women= 4/5

Question 28

Gueguen (2011)

Answer 28

-replication of Clark & Hatfield, conducted in france
-Confederates of various levels of attractiveness approached strangers and asked if they would have sex
-High attractive confederate (% that agreed):
men= 83% women= 3%
-Average attractiveness (% that agreed):
men= 60% women= 0%

Question 29

Clark & Hatfield, strengths

Answer 29

• It was a field study which increases the validity of the findings
• Because the pps did not know they were being studied, therefore are likely to act truthfully (no bias)
• Ecological validity
• Covert study= naive pps

Question 30

Which studies support C&H

Answer 30

• Gueguen because the men were more likely to then women (more recent study so overcomes temporal validity issues)
• Buss & Schmitt prove men are more will to have sexual partners than woman; its a questionnaire support for a similar type of hypothesis

Question 31

Criticism of C&H

Answer 31

• Limited sample; students on a university campus
• The women could’ve been fearful of the stranger (overcome in 1990 study)
• Cultural bias; westernised culture

Question 32

How did they overcome C&H’s issue in 1990

Answer 32

• They assured pps that the men were trustworthy and safe

- However this is not hugely convincing, as not stated how they convinced them

Question 33

Hypothesis 4: men will be attracted to indicators of fertility

Answer 33

• Men will be attracted to indicators of youth and fertility. Mating with younger females enhances the chances that they will be fertile - offspring
• One indicator for youth is waist- hip ratio (WHR). Before puberty the females figure is boy- like, i.e, straight up and down, but at puberty fat deposits on the hips, the waist narrows and the female body shape becomes more like an hour- glass.
• Male preferences will, then, be on indicators of a youthful figure. This type of figure will also be associated with higher fertility, better health, etc.

Question 34

Hypothesis 4: men will be attracted to indicators of fertility (Support studies -Singh et al, 1993)

Answer 34

• Aim: To investigate the waist-to-hip ratio (WHR) in terms of attractiveness in females.
• Procedure: The measurements of the Miss America Pageant winners and Playboy centrefolds over the previous 50 years were studied.
• Results: although factors like physique and body weight varied across the years, a WHR of around 0.7 was a consistent feature of female attractiveness.
• Conclusions: A WHR of 0.7 differentiates women from pre-pubertal females and signals that they are not already pregnant. It is associated with better health status and therefore potentially better reproductive capacity. This preference in men is therefore adaptive in maximising reproductive potential.

Question 35

Hypothesis 4: men will be attracted to indicators of fertility (Support studies -Singh et al 2009)

Answer 35

Researchers presented different WHR models to diverse racial groups to examine the universality of relationships between WHR and attractiveness. Results showed that in each culture participants selected women with a low WHR as attractive, regardless of increases or decreases in BMI. This cross-cultural consensus suggests that the link between WHR and female attractiveness is due to adaptation shaped by the selection process.
-Cross culture study

Question 36

Hypothesis 4: men will be attracted to indicators of fertility (Support studies - Karremans et al 2009) blind pps

Answer 36

• Karremans, et al explored men’s WHR preferences with one twist: the men in question were congenitally blind!
• this largely removes the possibility that these men were taught via media images to prefer a particular female body type.
• The researchers had two mannequins dressed in exactly the same way but who varied in terms of their WHR (0.70 or 0.84).
• The blind men touched both mannequins subsequent to which they provided attractiveness scores on a 1-10 attractiveness scale (higher meant more attractive). The goal here was to gauge the strength of the preference across the three groups, namely blind, sighted, and blindfolded men.
• For all three groups, the mannequin with the 0.70 WHR was preferred to the one with a WHR of 0.84.

Question 37

Sex differences in parental investment

Answer 37

• Parental investment involves investing time, effort or money in an infant in a way that increases the chances of that offspring’s survival and subsequent reproduction.
• Parental investment, then, is a way of enhancing ones chances of getting ones genes into subsequent generations.
• if parental investment increases such chances, that genes for parental investment would spread through a species.

Question 38

Trivers’ theory of parental investment

Answer 38

(i) whether they are genetically related
(ii) The extent to which they are genetically related
(iii) The certainty of genetic relatedness

Question 39

Trivers’ theory of parental investment: (i) whether they are genetically related

Answer 39

We would expect biological relatives to invest more in offspring than non- relatives. This explains why any parental investment occurs, i.e., it increases the chances of ones offspring/ relatives surviving and reproducing and, therefore, our own genes spreading.
-Step parents are less parentally invested as they aren’t genetically related

Question 40

Trivers’ theory of parental investment: (ii) The extent to which they are genetically related

Answer 40

We would expect parents to invest more than grandparents or uncles / aunts, because they share more genes.
-We share 25% of genes with these family members

Question 41

Trivers’ theory of parental investment: (iii) The certainty of genetic relatedness

Answer 41

Trivers argues that this is the core of the explanation of sex differences in parental investment. Men and women differ in the extent to which they can be certain that they are the parent of any (purported) offspring.

Question 42

Why does fertilisation lead to greater maternal then paternal certainty of paternity?

Answer 42

• Mothers can be certain that their child is theirs, whereas the father can’t be 100% certain. (as he doesn’t birth the child)
• You can’t tell which sperm has fertilised the egg

Question 43

What are the consequences of infidelity in men and women?

Answer 43

For men they could have multiple children with different partners, however, is could reduce their fertility if a women cheats as he doesn’t have a child when he could’ve, but the woman will have children either way

Question 44

What biological factors mean that women are more parentally invested into their children?

Answer 44

• The women carries the child and gives birth to the child, they risk their own survival in order to bring up the child so invest more time into it.
• They are also the only ones which can feed the child

Question 45

What are the strategies for men and women in order to pass their genes on

Answer 45

Women= investing more time into their children
Men= more effort into mating

Question 46

Cross-species comparison study

Answer 46

In species in which parental investment occurs, male investment varies. The basic pattern is especially pronounced in mammals, where male parenting is found in less than 5% of species and where females invest heavily in offspring (Clutton-Brock, 1991).
-In seahorses, the female inserts her eggs into the male’s pouch, where they are fertilised and hatch. Male seahorses invest more than females, and it is the females who compete for access to males. This leads to greater male than female paternal certainty, a reversal of the usual pattern, but one which supports Trivers’ theory that it is parental certainty that drives sex differences in investment.

Question 47

“Seahorses are the exception to the rule”

Answer 47

• Those who are the parental certainty invest more into the child.
• For humans this is always the female with parental certainty; however in seahorses the males have parental certainty sp therefore they are an exception

Question 48

Cross- cultural comparisons: investment of offspring (Geary 1998)

Answer 48

Geary conducted a cross- cultural study, drawing on anthropological data collected by others about parental care in a range of societies. He found that fathers spend less time interacting with and caring for their children than do mothers in all cultures that have been studied. He also found that the amount of time men spent on child care varies across cultures.
-Strong support as found in different societies so universal; evolutionary

Question 49

Cross-cultural comparisons: investment in mating

Answer 49

David Schmitt.

• Self-report measure of individual differences in mating strategy using the Sociosexual Orientation Inventory (SOI)
• Across 48 nations and 14,059 pps
• Found that sex differences in sociosexuality were large and demonstrated cross-culturally, universally across 48 nations- confirming several evolutionary theories of human mating.
• Strengths: Standardised self-report with good reliability and validity translated to each culture, cross-culture study, large sample

Question 50

Comparisons of investment by relatives

Answer 50

Euler & Weitzel (1996)

• Euler and Weitzel asked German adults to rate how much each biological grandparent had cared for them up until the age of seven.
• They found that the most amount of care given by a grandparent was in this order: 1. Mothers Mother, 2. Mothers Father, 3. Fathers Mother, 4. Fathers Father.

Question 51

How would parental investment theory explain the pattern of results in Euler & Weitzel’s study?

Answer 51

• Mothers mother has no degree of uncertainty so she knows that they must be her grandchildren and therefore invest the most time.
• Fathers father has the most degree of uncertainty and cannot be sure the grandchild is theirs

Question 52

Gaulin et al (1997)

Answer 52

Combined investment scores for relatives 
Maternal:
Aunt- 4.75
Uncle- 3.65
Paternal:
Aunt- 3.96
Uncle- 3.28

Question 53

Explain why maternal relatives invest more than paternal relatives.

Answer 53

-The maternal relatives can be sure that they are related to the child

Question 54

Comparisons between males and females in David Schmitts study

Answer 54

Men:
-More promiscuous 
-More mating
-Less investment 
Women: 
-More monogamous 
-Less mating
-More investment