Relationships - Evolution of Partner Preferences Flashcards
The influence of pheromones
- We select people with different scents as they will have a different genetic makeup due to different chemicals
- We seek out variations for our DNA as a more varied gene pool means less genetic diseases and so more longevity for the gene pool
Evolution processes for sexual selection
- DNA is inherited, these leads to variation - beneficial mutations survive better
- This means there is selection available
- Those who have a good gene pool are more likely to survive to adulthood and so reproduce
- Over generations this has changed our reproductive behaviour
Socio-biological explanation of sexual selection
- Men and women have different selection pressures
- Natural selection has led to the rise of sexual dimorphism
- Anisogamy means that sexual selection has become more important in females
- Natural selection favours female behaviours
Attractiveness:
Physical attractiveness -
> Males look for - Youth, fertility, healthy (skin, hair, hips)
> Females look for - Older, resource rich, kind
Body symmetry -
> Males look for - Waist to hip ratio, too small is not attractive (0.7 ideal)
> Females look for - Waist to shoulder ratio
Male strategies for improving their chances in sexual selection
1) Courtship rituals - allow males to display genetic potential, through characteristics and resource abilities
2) Size - males have evolved to be bigger, demonstrating strength for success in competition against other males - weaponry evolved in some species, for example antlers in deer
3) Sperm competition - natural selection acted on males, making them more competitive by producing larger testicles, bigger ejaculations and faster-swimming sperm; men only want their partner to have their sperm, as they want offspring
4) Mate guarding - males fear being cuckolded (another male get their partner pregnant) and spending resources raising another male’s child - males therefore engage in mate guarding to keep an eye on and remain in close contact with female partners to prevent them mating with other males (Buss; believes while men are fearful of partners being sexually unfaithful, females worry about emotional unfaithfulness due to a fear of their partner spending resources on other females
5) Sneak copulation - males mate with females other than their partners if given the opportunity as it increases their chances of reproductive success - women gain from this too, as having different fathers brings a wider genetic diversity to their children, increasing survival chances; females also gain an adaptive advantage having a resource rich male, while getting pregnant through a sneaky copulation with a genetically fit ‘stud’ though if found out she risks abandonment and being left to raise the child without male resources, research is somewhat contradictory with indications of varying levels of children born through sneak copulations
Female strategies for improving their chances in sexual selection
1) Sexy sons hypothesis - females select attractive males as they will produce sons with the same attractive features, increasing their sons’ thus their own reproductive fitness
2) Handicap hypothesis - Zahavi (1975) believes that females select males with handicaps as it advertises the ability to thrive despite handicaps, demonstrating superior genetic quality - this may explain females finding males attractive who drink or take drugs in large amounts as they are demonstrating an ability to handle toxin, a sign of genetic fitness
3) Courtship - females use courtship to select males on the basis of reproductive fitness, through males demonstrating health, strength and ability to provide resources - prolonged courtship rituals also benefit females as they make males invest time, effort and resources, increasing the chances of males not deserting after successful matings, and so investing more time in females and their offspring - thus human dating, with the investing of resources into a partner
Buss (1989) - mate preferences; predictions and aims of the study
Theories had long proposed that male investments and jealousy in relationships would differ - Buss looked to study this through the following lens’
- Resources; men invest less than females in the physical act of having a baby, therefore in order for the offspring to have a higher chance of survival, the male must provide more resources and make other ‘investments’; to this end, the researchers predicted females to place a higher value on characteristics related to earning capacity such as ambition than males would
- Youth and fertility - research shows that females are most fertile in their early 20s, and that this decreases with age - physical signs of youth are observable in healthy hair and skin and good muscle tone on women - the fertility of a man does not necessarily decrease throughout his life, and so researchers predicted that males would be more likely to value physical attractiveness than females because they are a stronger predictor of fertility for females than they are for males
- Certainty of paternity v maternity - there is never any doubt that the baby a mother is carrying is hers (excluding surrogates) and carries half of her genetic material, however, men have no way (apart from DNA tests) of knowing if offspring is theirs - some researchers propose that jealousy has evolved to serve an evolutionary purpose, by increasing paternal probability; chastity also serves the same purpose, by ensuring future offspring are definitely from the male partner, and researchers predicted males would value chastity more than females
Buss (1989) - mate preferences; methodology
Tested the above predictions using a range of genders and culture on heteorosexual male preferences:
- There were 10,047 participants from 33 countries and 37 cultures with a mean age of participants ranged from 16-28
- Participants were asked to rate 18 specific traits as 0-3 (0 = undesirable, 3 = indispensable)
- Examples of traits include good looks, chastity, ambition, industriousness, sociability
- Biographical information was collected on the participants and information on preferences regarding marriage
- They were also given 13 characteristics and they were asked to rank them in order from 1-13, examples of these characteristics being ‘good earning capacity’ and ‘physically attractive’
Buss (1989) - mate preferences and results / conclusions
Results:
- Females from 36/37 cultures valued good financial prospects higher than males, however, males preferred mates that were younger, while females preferred males who were older
- This result was cross-checked with other data and it shows that on average, men are older than women when couples are married - There were also moderate support for the gender chastity hypothesis, with males from 62%of the cultures valuing this more than females
- Interestingly, men from collectivist cultures tended to place higher values on chastity, and domestic skills than individualistic cultures - women from collectivist cultures tended to place higher importance on ambition, social status and financial prospects than women from individualistic cultures
Conclusions -
- Evolution and behaviour; because men across cultures had similar preferences, and so did the women, it suggests these preferences have a biological basis and are not a product of culture (because all of their cultures are different) and these results were similar to Buss’ hypotheses and perhaps we find particular qualities and features attractive because they give our offspring the highest chance of survival in the future
- Culture and behaviour - because there were some differences in preference across cultures, these could be explained by looking at the particular cultural values associated with individualistic and collectivist cultures; for example, men from individualistic cultures might place less emphasis on domestic skills because they have been raised to be more independent and look after themselves; collectivist cultures also tend to be more traditional with more defined gender roles and with stricter gender roles comes more preference for the qualities that would make someone successful in that role
Buss (1992) - Jealousy in males and females
Aim - aimed to see if males and females experience different forms of jealousy (sexual or emotional) in response to thoughts of infidelity
Methodology - male and female (American students were asked to think of a current or former partner becoming involved with someone else) and then they were asked if they would find either their partner forming a deep emotional attachment with X or having passionate sexual intercourse with X more upsetting. Some participants imagined the two scenarios while the psychologist response were measuring their pulse rate
Results - 60% of men (17% of women) were more distressed by the sexual infidelity scenarios and 83% of women (40% of men) were more distressed by the emotional infidelity scenario than the sexual one
- Men showed more physiological activity in the sexual infidelity scenario compared with the emotional one - women showed the opposite but the differences were not as strong as they were for men
CORE STUDY - Schutzwohl and Koch
Method:
- 100 male and female German students given 4 scenarios with two responses
- Participants were asked to vividly imagine the scenario with their current/previous partner
- Counterbalancing was used and choices along with decision time were looked at
Findings:
- Both sexes reported jealousy for emotional involvement
- More men than women (37/20%) chose sexual infidelity
- Times correlated with choice
Conclusions:
- Men who are more sexually jealous use less decision making strategies
- Instinctive response plays a role
Other research into sexual selection
- Davis - personal ads show differences in men and women
- Dunbar - women do not disclose age in personal ads
- Toma - males lie about education and income whereas females lie about weight
- Cartwright - symmetrical breasts are correlated with fertility
- Langlois - both men and women prefer symmetrical faces
Evaluation of sexual selection
- Evidence from sneak copulation found because it is looked for
- Oversimplified (heterosexual)
- Maximising reproductive success can also be explained socially
- Women do not need men as they once did and so theory is outdated
+ Evolution influences courtship behaviours too (eg: music)
+ Research support risky behaviours in men
+ Use of surgery and make up etc support female fertility
+ Real life application in pick up coaches
Intersexual and intrasexual selection
Intersexual selection -
- This is the idea that humans develop traits that make them attractive to the opposite sex, and make them the best choice for others
Intrasexual selection -
- This is the idea that humans develop traits that allow them to compete with their own sex, and ensures that they have the best chance of passing on their genes to their offspring
Traits that increase reproductive success can be seen in anisogamy, which is the difference in male and females resulting from different mating strategies.
