8. RELATIONSHIPS (Evolutionary Explanations for Partner Preferences) Flashcards
What is human reproductive behaviour?
Human reproductive behaviour refers to any behaviours related to opportunities to reproduce and increase the survival of our genes, including partner preferences and parental investment.
What is sexual selection?
Sexual selection is an evolutionary explanation of partner preference, where attributes or behaviours that increase reproductive success are passed on and may become exaggerated over generations.
How does sexual selection drive partner preference?
Males and females choose partners to maximise reproductive success through inter-sexual and intra-sexual selection, leading to the evolution of partner preferences in populations.
What is anisogamy?
Anisogamy refers to differences in male and female sex cells: sperm are small, mobile, and produced in vast numbers, whereas eggs are large, limited in number, and require significant energy.
What is inter-sexual selection?
Inter-sexual selection occurs between the sexes, where females prefer quality over quantity in a mate to ensure offspring survival.
How does anisogamy influence partner preferences?
It leads to females being choosier about mates (inter-sexual selection), while males compete for mates (intra-sexual selection) to maximise reproductive success.
What are key male and female mate preferences in inter-sexual selection?
Males prioritize youth and attractiveness (signs of fertility), while females look for resources and stability in a mate.
What did Singh (1993, 2002) find regarding waist-hip ratio?
Males prefer a waist-hip ratio of 0.7 in females, as it signals fertility and reproductive health.
What is the ‘sexy sons hypothesis’?
Proposed by Fisher (1930), it suggests that females prefer mates with desirable traits, ensuring their sons inherit these traits and are also preferred by future mates.
What did Buss (1989) find about partner preferences?
Across 37 cultures, men valued physical attractiveness, while women prioritized resources, supporting evolutionary explanations of partner preference.
What was a counterargument to Buss’ findings?
Buss and Schmitt (2016) found that both sexes seek kindness, love, and loyalty in long-term partners, suggesting less gender differentiation in mate preferences.
What did Clark and Hatfield (1989) find about male and female mate selection?
When asked by strangers for casual sex, 75% of males agreed, while 0% of females did, supporting the idea of female choosiness in inter-sexual selection.
What real-world examples support inter-sexual selection?
The existence of ‘trophy wives’, ‘gold diggers’, and ‘sugar daddies’ supports the theory that males seek youthful, attractive mates while females prioritize resources.
What is intra-sexual selection?
Intra-sexual selection occurs within a sex, where males compete for access to females, favoring traits like size, strength, and aggression.
How has intra-sexual selection influenced human dimorphism?
Males are on average 15% larger than females, as larger males had reproductive advantages in competition.
What behavioral traits result from intra-sexual selection?
Males may develop traits like aggression and intelligence to outcompete rivals, while females use verbal aggression to reduce rivals’ attractiveness.
What evidence supports intra-sexual selection?
Buss (1988) found men are more likely to use threats of violence in mate competition, while Daly and Wilson (1988) found that 90% of same-sex murders involve men in mate competition.
What is a limitation of sexual selection theory?
It does not fully explain homosexual partner preferences, as reproduction is not the primary aim, yet men still prefer attractiveness and women prefer resources.
How is evolutionary theory of partner preference deterministic?
It assumes mate selection is biologically driven, ignoring social and cultural influences such as changing gender roles and contraception use.
What is parental investment?
Parental investment is any investment by a parent that increases offspring survival at the cost of the parent’s ability to invest in other offspring.
Why do females have high parental investment?
Females carry offspring for nine months, have maternity certainty, and can only have a limited number of children, so they invest heavily to ensure offspring survival.
Why do males have low parental investment?
Males have low paternity certainty and produce millions of sperm, so investing in many mates maximizes reproductive success.
How does parental investment support sexual selection?
Women, due to high parental investment, are choosier (inter-sexual selection), while men compete for mates (intra-sexual selection).
What did Clark and Hatfield’s (1989) study reveal about parental investment?
Women’s reluctance to casual sex supports their higher parental investment, while men’s willingness supports their strategy to maximize reproductive success.
How has changing social norms affected parental investment theories?
Women’s increased independence and access to contraception challenge traditional evolutionary explanations, as resource-based mate preferences may be declining (Bereczkei, 1997).
