Biological explanations of Relationship formation

What is the Evolutionary Theory?

Evolutionary Theory describes the innate desire of males and females to reproduce.

We are drawn to seek a mate who has particular biologic characteristics. These are related to our evolutionary desires to reproduce.

What do Evolutionary explanations describe? + Parental Investment Theory

Evolutionary explanations describe the formation of relationships between males and females in terms of Parental Investment Theory. (Trivers, 1972) which proposes that one factor that affects mate selection is parental investment.

He proposes that the sex investing more in offspring (usually the mother) will have a strongerpreference about mating partners.

What did Trivers claim?

Trivers claimed that the formation of romantic relationships is driven by evolution, specifically how each sex has a different level of investment in ensuring their offspring survives in order to pass on the family genes.

In humans, females invest more time and energy in reproduction than men. Male investment is minimal while female investment is greater as she then carries the child through pregnancy, and takes the majority of the responsibility of child rearing into adulthood.

What are women likely to be due to their high parental investment?

The fact that women invest more in reproduction means that they will be choosier in their mate choice.

It also means that women's selection of men should be influenced by their ability to contribute to childrearing - this theory suggests that women will favour ambitious, hard-working and rich men who are most likely to be able to look after them and their children.

The male must have lots of resources for her and her child. The female also looks for a male who is older than her because he is more likely to have such resources.

How much do men invest in their offspring?

However, men do not invest much in their offspring. They can have many children with many different women in a very short space of time. Once the male impregnates the female, there are no risks to him because he is not physically involved in the pregnancy.

Therefore, men look for signs of youthfulness and reproductive success in a female, such as smooth skin, white teeth, wide hips and large breasts. These are all signs of good genes and the ability to carry and feed their offspring successfully.

What did Symons believe?

Symons believed that males look for females who have high reproductive value meaning they look for a female who is able to have many children over a long period of time, e.g. a girl aged 13 has a high reproductive value as she could produce babies for around 40 years.

Opposingly, What did William state?

Williams stated that males would look for a female who had high fertility. Therefore, even though a 13-year-old female may be able to have offspring for many years, her fertility would not be good enough and she could not look after a baby successfully.

For that reason, males should look for a female who is very fertile, but who can also look after herself and her offspring, e.g. a woman aged 23 has high fertility.