The relationship between sexual selection and human reproductive behaviour:
Sexual selection: An evolutionary explanation for partner preference, suggesting that attributes beneficial to survival and which increase reproductive success (so are adaptive) are passed on through genes. Therefore, human reproductive behaviour, including mate choice preferences, are affected by evolution.
Anisogamy: The difference between male and female sex cells. For females, they have a finite supply of eggs, only one of which is released each month, meaning it requires much more effort to produce the sex cells (gametes) than males. Males produce large numbers of sperm continuously. This leads to a difference in mating strategies between males and females, and within the genders.
Inter-sexual selection: Refers to strategies one sex uses to select a partner from the opposite sex. This tends to be the strategy females use, as there is a greater investment required to produce an egg, and (historically) females would invest greater time and commitment in the raising of offspring. Therefore, females are much more choosy as to which partner they mate with in order to invest all of these resources. Males end up competing with each other to be ‘selected’ by a female. Certain characteristics that are seen as attractive are more likely to persist, as the male will be chosen for that characteristic, have a son which will inherit the trait, which will be passed down to their son, and so on. If they have a daughter, the preference for the characteristic will be passed down to the daughter. This is known as a ‘runaway process’.
Intra-sexual selection: Refers to strategies one sex uses to be the one that is ‘selected’ by the other sex. This is the preferred strategy of males- the winner of the ‘competition’ between males gets to mate with a female. The characteristics that made them the winner get passed down through generations, leading to ‘dimorphism’- the obvious physical differences between males and females. Physically larger males would be more likely to defeat rival males, whereas there is no need for females to be physically large. Therefore, males are on average physically larger than females. Other characteristics which may be useful for males are aggression, and also a mate choice preference for younger females, who are more likely to be fertile.
- Buss (1989) questioned 10,000 adults in 33 countries about mate choice preference- what they would look for in an ‘ideal’ partner. He found that females preferred resource-based characteristics (such as a good career), whereas males preferred physical attractiveness and youth. This was true across all the countries surveyed. This supports the difference in mate choice preferences related to anisogamy.
- Clark and Hatfield (1989) found that when male and female university students were propositioned by an opposite-sex stranger on campus, 75% of males agreed to the request to spend the night together, whereas no females did. This supports the evolutionary theory that females are much choosier than males when it comes to selecting a mate.
- The theory does not account for major social and cultural changes which may affect reproductive behaviour. There is some evidence of changes to mate choice preference following changes such as the lack of female dependency on a partner. Therefore, mate choice is likely to be influenced by more factors than just evolutionary preferences.
Factors Affecting Attraction: Self-disclosure
Self-disclosure: This refers to the revealing of personal information to a partner, for instance likes and dislikes, hopes and fears, deepest thoughts and feelings. This can strengthen the romantic ‘bond’ between partners.
Social penetration theory: Altman and Taylor (1973) suggested that over time, couples reveal more and more information about themselves. The revealing of sensitive information from one partner encourages the other to respond in kind, leading to more and more information being shared between the couple. This deepens their understanding of each other and makes the relationship more emotionally intimate.
Altman and Taylor suggest that the breadth and depth of self-disclosure is important, using the metaphor of an onion. In the early days of a relationship, only the outer, superficial layers are revealed, and there is a narrow breadth of information offered. Sharing too much information at this stage can be off-putting to a partner. Over time, the deeper, more important layers are shared, eventually leading to the revealing of intimate, ‘high-risk’ information such as deeply-held secrets.
Reciprocity of self-disclosure: Reis and Shaver (1988) suggest that for a relationship to develop, there needs to be reciprocity in information-sharing. Once a person reveals something intimate about themselves they expect their partner to respond in kind. This strengthens the relationship by increasing feelings of intimacy and connectedness.
- Sprecher and Hendrick (2004) found strong correlations between measures of satisfaction in relationships and levels of self-disclosure. High levels of self-disclosure were associated with more satisfaction, supporting the predictions of social penetration theory.
- There are useful real-life applications for this theory. If people can be encouraged to be open, honest and share intimate information with their partner, this may increase the likelihood of a relationship being successful, leading to greater satisfaction and happiness.
- Self-disclosure may be a limited explanation. Findings from collectivist cultures suggest that partners may reveal less about themselves, namely sexual preferences, than what is shared in individualist cultures. This means the explanation may be less applicable to all cultures.
Factors Affecting Attraction: Physical Attractiveness
Physical attractiveness: Refers to what people find appealing about a person’s face and body. Despite individual differences, there is a general consensus on what is physically attractive. This could be explained through evolution. Physical features considered attractive are often signs of fertility or genetic fitness, for example facial symmetry, waist-to-hip ratio, and so on. This would be expected to be an important factor in the formation of relationships.
The halo effect: Dion et al (1972) found that physically attractive people were rated highly on characteristics such as kindness, strength, sociability and other positive traits. Therefore, people who are attractive physically are more likely to be treated more positively, as others tend to think positively of them. This is referred to the halo effect- one characteristic (physical attractiveness) has a disproportional effect on other judgements about a person.
The matching hypothesis: Walster et al (1966) suggested that people choose romantic partners of a roughly equivalent level of attractiveness to themselves. This involves being able to make an accurate judgement about their own attractiveness level. This is partly because, practically, not everyone can mate with the most attractive people, but also to avoid the person being rejected by someone more attractive than them. There may be a difference between what a person would like, and what they would ‘settle for’ in a relationship.
- Palmer and Peterson (2012) found that physically attractive people were rated by participants as more politically knowledgeable and more competent than unattractive people, so supporting the concept of the halo effect.
- Feingold et al (1988) found a significant correlation in ratings of attractiveness between partners in a meta-analysis of 17 studies, supporting the matching hypothesis.
- Taylor et al (2011) found that, when studying mate choice preferences on a dating website, people tended to try to meet potential partners who were more physically attractive than them, seemingly not considering their own attractiveness level. This weakens the matching hypothesis, as it is not consistent with how men and women would be predicted to act.
Jim has recently joined a dating website and his friend Julie is helping him pick which women he should message asking to meet up. ‘What about this one?’ asks Jim. ‘No!’ Julie replies. ‘She’s much better-looking than you are, no offence! You need to be more realistic about who you ask.’
- Use your knowledge of the matching hypothesis to explain Julie’s comments. (4 marks - 1-2 paragraphs).
- Your answer should include: Similar / Attractiveness