Evolutionary Explanations

Question 1

Sexual selection.

Answer 1

An evolutionary explanation of partner preference; attributes or behaviours that increase reproductive success are passed on and may become exaggerated over succeeding generations of offspring.

Question 2

Darwin’s (1871) concept of sexual selection concerns…

Answer 2

The selection of characteristics that aid successful reproduction.
Physical characteristics determine signs of genetic fitness.
Adaptive characteristics - provide an advantage for a male over competitors for reproductive rights.

Question 3

Anisogamy.

Answer 3

The basis of human reproductive behaviour.

Refers to the differences between male and female sex cells.

Question 4

Male gametes.

Answer 4

Small, highly mobile, created continuously in vast numbers from puberty to old age and don’t need much energy to be produced.

Question 5

Female gametes.

Answer 5

Relatively large, static, produced at intervals for limited number of fertile years and require significant investment of energy.

Question 6

Consequence of anisogamy.

Answer 6

No shortage of fertile males but a fertile female is a much rarer ‘resource’.
Anisogamy is important in partner preference between it gives rise to two types of sexual selection.

Question 7

Two types of sexual selection.

Answer 7

Inter-sexual selection.

Intra-sexual selection.

Question 8

Inter-sexual selection.

Answer 8

Between the sexes - the strategies that males use to select females or vice versa.
The preferred strategy of the female, quality over quantity.

Question 9

The female preference determines…

Answer 9

which features are passed on to the offspring.

Question 10

(Inter) Robert Trivers (1972).

Answer 10

The female makes a greater investment of time, commitment and other resources regarding offspring.
Both sexes - choosy, because both stand to lose if they invest resources in substandard partners.
Consequences of making wrong partner choice - more serious for females, hence more selective and females optimum strategy is to select genetically fit partner who is able to provide resources.

Question 11

(Inter) Ronald Fisher (1930) - Sexy Sons Hypothesis.

Answer 11

The genes we see today are those that enhanced reproductive success.
A female who mates with a male who has a certain characteristic then will have sons inheriting this ‘sexy’ trait. Then her sons more likely to be selected by successive generations of females who will mate with her offspring. Therefore the preference of this ‘sexy’ trait is perpetuated.

Question 12

Intra-sexual selection.

Answer 12

Within each sex - the strategies between males to be the one that is selected.
Preferred strategy of the male, quantity over quality.
Winner of competition between males produces and therefore the characteristics that contributed to his victory may be passed on to his offspring.

Question 13

Intra-sexual selection given rise to dimorphism.

Answer 13

Males and females end up looking very different because of intra-sexual selection.
Larger males have an advantage and are therefore more likely to be reproductively successful.
Females do not compete for reproductive rights so there is no evolutionary drive towards favouring larger females.
In females youthfulness is selected because males have a preference to mate with younger more fertile women.

Question 14

(Intra) Behavioural consequences.

Answer 14

Favoured characteristics are passed on are those that allow a male to outcompete his rivals.

Question 15

Strength: evidence to support the predictions of sexual selection theory.

Answer 15

David Buss (1989) carried out a survey of over 10000 adults in 33 countries. He asked questions relating to a variety of attributes that evolutionary theory predicts are important in partner preference. 
He found that females placed greater value on resource-related characteristics than males did, such as good financial prospects and ambition. Males valued physical attractiveness and youth more than females did.
These findings reflect consistent sex differences in partner preferences and support the predictions from sexual selection theory.

Question 16

Limitation: Evolutionary theories overlook the influences of social and cultural factors on partner preference.

Answer 16

Partner preferences over the past century have undoubtedly been influenced by rapidly changing social norms of behaviour; these develop much faster than evolutionary timescales imply and have instead come about due to cultural factors.
Women’s greater role in the workplace means they are no longer dependent on men to provide for them. Tamas Bereczkei et al (1997) argue that this social change has consequences for women’s mate preferences, which may no longer be resource-oriented.
Therefore, partner preferences today are likely to be the outcome of a combination of evolutionary and cultural influences. Any theory that fails to account for both is a limited explanation.

Question 17

Strength: Evidence supporting the specific role of female choosiness in heterosexual partner preference.
Counterpoint inclu.

Answer 17

Clark and Hatfield (1989) sent male and female psych students across a university campus. They approached other students individually with this question: ‘I have been noticing you around campus. I find you to be very attractive. Would you go to bed with me tonight?’ Not a single female student agreed, whereas 75% of males did.
This supports the view that females are choosier than males when it comes to selecting sexual partners and that males have evolved a different strategy to ensure reproductive success.
The argument from sexual selection that one strategy is adaptive for all males and another is adaptive for all females is simplistic. At the very least it appears that strategies differ according to the length of the relationship. Sexual strategies theory (Buss and Schmitt 2016) argues that both males and females adopt similar mating strategies when seeking long-term relationships. Both sexes are very choosy and look for partners who are loving, loyal, and kind, for e.g.
This is more complex and nuanced view of how evolutionary pressures influence partner preferences which takes account of the context of reproductive behaviour.

Question 18

Limitation: There are many methodological weaknesses in the research which evolutionary psychologists’ use to support their claims that women prefer high-status and well-resourced men.

Answer 18

Most of the studies into females choice of mates were carried out on undergraduate students. As these women were expected to achieve a high education status leading to a secure income, their preference for high-status men may stem from similar interests and prospects, rather than an innate mechanism. Furthermore, research into evolutionary explanations may also lack validity since studies only measure expressed partner preferences rather than real-life ones. Since research often takes a retrospective approach, largely based on speculations about what may or may not have been evolutionary adaptive for our ancestors, it means that there is no reliable way to check whether these suggestions are valid.