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A2 Psychology - Relationships lesson 2

Human reproductive behaviour

Amanda Lane

on 28 June 2015

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Transcript of A2 Psychology - Relationships lesson 2

Human Reproductive behaviour
A2 Psychology - Relationships
Lesson Objective
During non-fertile periods of their menstrual cycle, both sets of women were earning the same amount of money. However, the women who were not on the pill, earned twice as much as those on the pill when they entered their fertile period
Natural selection V's
Sexual selection
Mate Choice
So how have the sexual selection traits evolved over the natural selection traits?
Mental Characteristics
To explore the theories that explain human sexual behaviour and mate choice.
According to Darwin (1871) the nature of sexual selection is to be successful in attracting a mate which in turn enhances the success of natural selection. So what happens if sexual selection 'interferes' natural selection? (Traits which enhance survival)
Humans are naturally picky when it comes to mate selection as we want the best possible combination of genes for our offspring, as well as passing on successful selection traits and characteristics.
Our brain size has tripled over the last 2 million years of evolution so it comes as no great surprise that mental characteristics are highly sort after in mate selection, especially the neophilic aspects in people such as music and literary talents, humour, artistic qualities etc.
Investigating sexual selection theory
One of the key assumptions of SST is that men are attracted to women who are fertile and healthy. Another key aspect is that women need to be 'in OESTRUS' (ovulating and the ability to become pregnant), so how do men know this?
Miller et al. (2007)
Compared the earnings of lap dancers who were menstruating naturally with those who were menstruating on the pill. The pill prevents oestrus as you cannot become pregnant.
What reasons can you attribute for this difference in earnings?
So what is
'sexual selection'?
Darwin states that competition for mates between individuals of the same sex affects the evolution of certain traits. Theses traits will enable individuals to have characteristics that will ensure sexual success against rivals in competition
Take the humble peacock....
To ensure sexual selection success, a male peacock's plumage is large, bright and vivacious....
However, the tail feathers are cumbersome, inhibits flying and advertises the peacock to predators. Its mating call also attracts attention by informing predators of its whereabouts.
Darwin theorised that survival of the fittest is in part the ability to reproduce so in this sense the peacock's plumage is more about 'survival of the sexiest'
This theory can also be applied to humans and the 'hour-glass' figure which has been found to be the most attractive to men across many different cultures. This would make sense as curvy women are synonymous to fertility and health
There are 4 main criteria for mate selection
Mate choice is based on visual indicators that denote health, age, fertility, strength, disease resistance etc
Mate selection can be determined by the giving of gifts! This is true in animal species giving gifts of food.
Facial Preferences
The human face is an important aspect when choosing a mate. But why are some faces considered more attractive than others?
Attractive faces are an advert for 'good genes' and something you would want for your offspring to enhance their future sexual selection success.
Testing sexual selection in real life!
Look at the lonely heart ads and fill out the table!
Can you apply the sexual selection theory to real life? What evaluative flaws can you identify with the theory?
Casual sex
A consequence of sexual selection is the evolution of sexual strategies such as casual sex
However, there are greater consequences for women than there are for men!
Clark & Hatfield (1989) conducted a casual sex experiment to see if there were sex differences in the frequency it was carried out!
Sperm competition
In many animal species, females will mate with more than one male so sperm competition will determine which male's sperm will fertilise the egg
Testicle size has been linked with the idea that the more sperm you can 'offload' the better the chance of winning the sperm competition!
For example...
Chimpanzees are highly promiscuous so males have large testicles in relation to body size.
Gorilla's however have very small testicles as there are usually 2 or 3 females to one male. Gorilla's are monogamous so do not need to worry about sperm competition from other males.
Human males on the other hand had medium sized testicles which suggests that females are moderately promiscuous.
Evaluating sexual selection theory
In terms of reproductive behaviour, SST states that we have sexual preferences but who we actually end up with in a long-term relationship maybe someone totally different!
Attractiveness may not be the result of social convention but more of an evolved behaviour.
Women's perception of attractiveness changes depending on the position within her menstrual cycle
People choose partners on more than just looks!
To apply these theories in order to understand how relationships are formed
Lesson Outcome
According to

the way in which we select a potential mate is determined by behaviours that are innate which aids our survival.....
Where have we encountered the evolutionary psychologists before?
Choosing a mate... EVO style!

Men tend to choose female mates that have 'child' like characteristics such as large eyes, small nose and full lips.
which is identified by smooth skin, glossy hair, red lips, slim waist.
women are attracted to men with masculine facial characteristics such as a large jaw and prominent cheek bones.
identified by athletic figure which is synonymous with the ability to provide
Females look for:
Males look for:
women will enhance their physical appearance and attractiveness because it is expected that men will seek it.
Men will advertise their wealth and status because it is expected that women will seek such qualities when looking for a mate.
Sexual selection theory... the ins and outs
How is this approach different to the theories we looked at last lesson?
Full transcript