Evolutionary Explanation For Partner Preferences Content Flashcards
How does Darwin’s theory of natural evolution extend to partner preferences?
Sexual selection = survival of the sexiest, where sexy is defined as traits that increase reproductive success, meaning they become more adaptive as you are more likely to become involved in creating new offspring
What kind of traits are adaptive in sexual selection?
Different for males and females, but they are the traits that can enhance the chance of reproductive success as they will produce more offspring
Which traits can help individuals gain a reproductive advantage in males and why?
. Strength
. Height
. Aggression
- these signal to the female that they are prepared to offer protection to their partner and their offspring, and are willing to fight against any competition.
- these traits are desired by females for reproductive purposes so help you do well in sexual selection
Which traits can help gain a reproductive advantage in females and why?
. Wide hips = sign of fertility
. Good looks = ‘good looking’ offspring genes = traits will be passed down and make the offspring’s characteristics adaptive for sexual selection.
. Younger = greater reproductive success as holding more eggs in ovaries
What two ways do sexual selection operate and how are they linked?
- Intra-sexual selection = mate competition
- Inter sexual selection = mate choice
Inter-sexual selection leads to intra-sexual selection as the preferred traits are chosen and competition is initiated for these adaptive traits in sexual selection
What is intra sexual selection?
Usually occurs in males, when one sex must outcompete others of their sex to mate with the opposite sex and produce offspring and pass on their genes. The winners will possess the traits desired by the opposite sex and the losers won’t have their genes passed on at all.
What is intersexual selection?
One sex (usually females) evolves preferences for desired qualities in opposite sex potential mats based on the value of the qualities in producing ‘good’ offspring. This means that the opposite sex possessing these preferred traits will have a reproductive advantage and this will determine the areas that the opposite sex will compete over.
What is the runaway process?
How reproducing with the same desirable traits over time will develop these desirable traits over time and make them more pronounced so offspring become more and more adaptive for sexual selection - ‘sexy son hypothesis’
What kind of mate preferences are females looking for in the long-term?
Quality, as they only possess so many eggs and their investment is huge as once offspring is created, there is a need to stay and nurture the offspring.
. Attracted to males who can invest and provide resources for her and the child.
. Able to physically protect her and her children
. Promise of a good parent
. Sufficiently compatible to ensure high-quality offspring genetics.
How is random mating viewed in evolutionary theory?
Almost as stupid mating, as maladaptive genetic traits will be passed on, impairing the survival of the offspring in sexual selection.
What kind of mate preferences are males looking for in the long term?
They are mainly looking for quantity over quality as they don’t require high investment due to their vast amounts of reproductive resources, making the process of mating less valuable for them. (Could just smash and run)
. Nonetheless, males don’t just give their resources to anyone
- they want females that show signs of fertility as this shows reproductive value
What do the differences in investment in offspring in males and females arise from?
Anisogamy - the differences between male and reproductive cells
- loads of sperm vs around 300 eggs + 9 month pregnancy makes it much more significant for female to engage in mating (they are usually more choosy)
What did Buss 1989 study?
What males and females looked for in long-term partners
What was the procedure of Buss 1989?
. Sample: more than 10k people from 37 different cultures
. Had to rate each of 18 characteristics on how important they would be in choosing a mate such as physical attractiveness
. Four point scale used where 0 = irrelevant, 3 = vital
What are the findings of Buss 1989?
Women wanted:
. Men with resources and ‘good financial prospects’, translating to qualities such as ambition
Men wanted:
. Physical attractiveness as this hints to fertility
. Mates who are younger than them - sign of increased fertility
Both sexes wanted:
. Kindness = interest in long-term relationships
. Intelligence = skilled parenting
Which study looked into sexual jealousy and how?
Buss 1992: asked participants to imagine their partners having sex/falling in love with someone else and measured stress response
Why does sexual jealousy make sense in evolutionary terms?
There is a fear of cuckoldry - raising offspring not genetically related to you - as you put in the investment and time to give your resources and reproductive advantages to your partner and offspring.
What are human reproductive strategies to try and win competition in sexual selection?
. Male courtship rituals - showing off your ‘saleable’ and attractive genes
. Sneak copulation - evolutionary-speaking ‘low quality’ males mates with ‘low quality’ female
. Sexy sons hypothesis (Fisher)
