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How many marks would this exam obtain in Psychology A2 PSYA3?

This exam, which I'm going to paste below in blue, someone said to be a model answer. The question is out of 25 marks, and how much should we be writing in this exam for each question?

Discuss the relationship between sexual selection and human reproductive behaviour (25 marks)

The Darwinian concept of sexual selection involves the notion that any physical trait that enhances reproductive success will gradually be passed down and enhanced over evolutionary time. Evolutionary psychologists explain the relative hairlessness of humans in terms of sexual selection, as this trait was adaptive in that it enhanced reproductive fitness by indicating hygiene. It has therefore evolved and developed over the centuries as it confers a net benefit. Intra-sexual selection involves men competing with each other for access to females. As a consequence of this, men have evolved larger, more triangular backs, as this indicates strength and makes the individual more attractive to females; another example of sexual selection at work. Inter-sexual selection on the other hand, involves the apparent “choosiness” of females. Females invest highly in their offspring, and as a consequence, seek partners that can provide resources and protect them from predators. As a result of sexual selection, both males and females have evolved certain mate preferences which in turn, has lead to the evolution of certain physical characteristics.

Current mate choices evolved in the EEA, and were adaptive in mobile hunter-gatherer tribes. These choices now exist as neural circuits which bias our mate preferences. An example of this bias is the desire for attractive, symmetrical faces. Little & Hancock propose that humans have evolved to be attracted to symmetrical faces because they indicate “averageness”, which equates to genetic health. Furthermore, it has been proposed that sexual selection has caused males to develop fairly large testicles, as this is a way of compensating for female promiscuity. Studies show that chimpanzees, which have highly promiscuous partners, have large testes, whereas gorillas, which have faithful partners, have relatively small testes. Humans are somewhere in the middle, implying that human females are moderately promiscuous. Female choice has created a selective pressure among males, and according to evolutionists, men have developed large, square jaws to display their strength, which attracts females. Females in comparison have evolved large eyes and a curvaceous body in order to indicate fertility, which is a result of the selective pressure from males to seek females who are going to produce the best children.

In support, Buss analysed lonely hearts columns across 37 countries, finding that universally, men seek fertility and attractiveness; and women seek resources and protection. These findings are in line with Darwin’s theory of sexual selection, and the strong cross cultural agreement implies that such mate preferences originated from our evolutionary past, as opposed to being learned. However, this study has attracted a number of criticisms, and studying personal ads may be unrepresentative, as individuals may exaggerate or lie about their mate preferences in order to conform to the cultural norm. Nevertheless, much research supports the idea that women are attracted to males with a lot of resources, and Hill and Kaplan have found that in the !Kun-San tribe, the best hunter-gathers have the most wives, which supports sexual selection theory.

The evolutionary approach does raise ethical concerns however, as sexual selection theory ultimately justifies infidelity in males and dismisses deviant acts such as rape to be evolved and adaptive behaviours which enhance reproductive success. Such a view is unsurprisingly, attacked fiercely. As well as this, Dunbar, who also studied personal ads, found that gay males are less likely to offer resources and lesbians are less likely to look for them in partner. This highlights a weakness of sexual selection theory, as it cannot account for the fact that some people are homosexual, and some couples elect to be childless. However, much research supports the idea that certain traits have evolved over evolutionary time, and Perrett et al. have found a strong cross cultural agreement for facial attractiveness. Furthermore, Langlois et al have found that an interest in attractive female faces develops within the first year of infancy, which implies that such a mate preference is innate and evolved.