Sexual selection and human reproductive behaviour Flashcards
Sexual selection
Traits that promote survival will be attractive to the opposite sex, and therefore encourage breeding and passing on of these traits
Anisogamy
Refers to the difference between male and female
Male cells (sperm) are plentiful because they are relatively ‘cheap’
- Small
- Highly mobile
- Created continuously in vast n.o from puberty to old age
Female cells (ova) are ‘expensive’ because they require more energy to produce them
- Relatively large
- Static
- Produced at intervals for a limited n.o of fertile years
Consequence of anisogamy
There are plenty of fertile males but fertile females are a ‘rarer resource’
This gives rise to mating strategies i.e inter sexual and intra sexual
Inter-sexual selection
Selection of mates between sexes i.e females select males/males select females
Females make a greater investment of time, commitment e.t.c before, during and after birth (Trivers)
Female’s optimum mating strategy is to select a genetically fit partner who is able to provide resources
Fisher: can get out of control
- lead to a runaway selection
- characteristics become extreme and unhelpful in the long run
- how much human behaviour has become built in but unhelpful in the long run
Intra-sexual selection
Selection of mates within sexes i.e males compete with other males for mates
Males compete for females as sperm is plentiful but fertile females are limited resource and are choosy
Males who ‘win’ pass on their genes to the next generation so the traits that contributed to their victory (e.g height/cunning) are perpetuated
Intra-sexual selection pressures lead to certain patterns of human reproductive behaviour:
Physical consequences - size is selected in males (e.g males who are bigger win mates)
Behavioural consequences - male aggressiveness also helps win competitions
What are the two strengths
2 types of research support which are:
> Buss
> Clark and Hatfield
Evaluation: Research support (Buss)
It is supported by research that certain partner preferencesare evolutionary.
Buss conducted a survey involving over 10,000 adults across 33 countries, and the results indicated that women often gave more importance to attributes associated to resources in a partner, such as stable finances. On the other hand, males valued a female’s potential for reproduction more than her beauty or modesty, and they preferred younger partners.
Thisuniversallysuggests that partner choices are an evolutionary response to maintain survival and healthy reproduction.
Evaluation: Research support (Clark and Hatfield)
There is additional research support for the idea that females are more careful when selecting a partner
For example, Clark and Hatfield used female choosiness as an illustration. On a university campus, they requested that male and female student volunteers approach different-sex students individually and ask the identical question: “I’ve noticed you around campus.” Would you like to spend the night in bed with me? I think you’re really attractive. They discovered significant differences in gender in the answers. Among the male students, 75% agreed; not a single female student replied yes. But like many other studies on the topic of relationships, this one has drawn criticism for having a small sample size that may not accurately reflect all kinds of relationships
Although this study supports the view that females are choosier than males in partner preferences but we are unable to conclude whether a non student, older sample would be as selective therefore we do not know if evolutionary explanations explain partner preferences in all females.
What is a limitation
Suffers from evolutionary reductionism and determinism
Evaluation: Suffers from evolutionary reductionism and determinism
The claim that partner selection techniques are a function of genetic inheritance and the desire for successful reproduction is evolutionary reductionism, which undermines evolutionary theories of relationships. In reality, though, this is not usually the case as partner preferences vary greatly from person to person. For example, homosexual partnerships, where selecting a partner clearly has no reproductive advantage and does not lead to successful reproduction, are not explained by evolutionary theories.
Similar to this, evolutionary explanations of relationships suffer from determinism because they supposedly imply that a person’s gender determines their choice strategies and that people are drawn to those who will have, raise, and/or care for offspring.
