According to evolutionary psychologists, whatever pressures our ancestors face when it came to reproduction still affect our behaviour today

The consequences of casual sex are greater for women who may be left pregnant with 'poor quality' offspring, no partner, reputational damage etc.

The more females a male impregnates, the greater his reproductive fitnesss

Female gametes are less numerous and more costly to produce than male gametes

A woman produces one egg a month but a man can produce billions of sperm in one ejaculation

A female can only have a limited number offspring whereas men can have an unlimited number

For men, to maximise their reproductive fitness, they need to have as much sex as possible

For women, reproductive fitness means finding one man who will give her children and stick around to support them long term

Attractive male and female researchers approached strangers on a university campus and asked if they wanted to have sex

Found sig. differences in male and female motivation for casual sex

This is evidence that men have evolved psychological mechanisms to ensure success in short-term mating

Found men show a marked decrease in attraction for their casual sex partner following sex

This is allegedly an evolved adaptation which prevents men wasting time with one woman

Darwin (1874) proposed his theory of sexual selection which explains that reproductive fitness must have been enhanced through such features

An important feature of most species is that males are brightly coloured

It also affects the strategies they take to choose a partner and has given rise to 2 types of selection

Anisogamy and reproductive fitness therefore affect male and female attitudes to sex

Members of one sex compete with each other for members of the opposite sex

This form of selection involves the preferences of members of the opposite sex who possess certain qualities

The preferences of one sex therefore determine the areas in which the other sex must compete

Wanted to explore whether there were universal mate preferences

Across all cultures, women wanted men who had resources or traits that would translate to resources

The fact that the same preferences existed everywhere, indicate that sexual selection is an innate, natural mechanism and not on affected by nurture

In the EEA, for women engaging in casual sex, this would have been a huge risk as they would have been left as single mothers

However, we now have contraception which reduces pregnancy risk and alters female sexual behaviour

Women can now engage in as much casual sex as men without fear of consequences

Psychologists maximise the difference between the sexes ie. men are viewed as uncaring, irresponsible whilst women are viewed as monogamous, caring and responsible

Baby face, button nose, delicate chin, big eyes, neotenous

Couples who are matched are more likely to have happy, enduring relationships

The more socially desirable a person is, in terms of physicality, social standing, intellect etc. the more desirable they would expect a partner to be

Walster referred to this notion as realistic choices because each individual is influenced by the chances of having their affection reciprocated

The success of these random matches were assessed using questionnaires during the dance and then 6 months later

Before the dance, the more attractive the student, the more attractive they assumed their date would be

They believed they had been matched with their date even though they were randomly allocated partners

Once ppts had met their matches, they reacted more positively to physically attractive dates and were more likely to try to arrange subsequent dates with them

752 undergrads at University of Minnesota were invited to a dance

Individuals continuously tried to arrange dates with people considered more attractive than themselves

Proposed that people want to be with someone more physically attractive than they are, to increase the child's genes

Carried out research on real online dating sites and no support for realistic choices

Photos of random men and women were shown independent judges who rated each picture out of 20

When they were put back together, the ratings matched with the correlation being high enough to be statistically significant

Found a more significant effect of matching hypothesis in committed couples compared to casual couples (Cavior & Boblett, 1972)

In reality, matching is more complex, for example someone may not be physically attractive but has a lot of money

Physical attractiveness of women is valued higher by men but that of men is valued less by women

This implies that men can compensate for any deficit in physical attractiveness with other qualities more than women

Takeuchi (2006) has shown that a gender difference exists in the degree to which physical attractiveness is valued

Matching is sometimes influenced by third parties such as family or even dating sites

Found that men and women were more concerned with their partner being trustworthy, supportive and warm over physicality

Suggests that physical attractiveness may not be as deterministic as the matching hypothesis sets out

Psychologists believe that in successful relationships, partners are careful with the pace at which they reveal personal info

At first, they reveal relatively little personal info but this increases more and more over time as we build trust and want the relationship to progress

Once one partner discloses something difficult, it is important that the other partner responds appropriately with empathy, respect and an equally difficult personal disclosure

The relationship is only successful if both partners are equally willing to self-disclose

Relationships will be successful if both partners reciprocally self-disclose over time

However, as a relationship develops and trust builds, we disclose more complicated feelings, making the relationships stronger

The correct pace and style of self-disclosure seems to have become an implicit social norm

At the outset of a relationship, breadth of info is narrow because lots of topics are off limits

These studies suggest that we can have confidence in the validity of the theory

Surveyed heterosexual couples and found a strong positive correlation between the amount of self-disclosure occurring in a relationship and reported satisfaction

Surveyed 50 heterosexual couples and found that the amount of overall self-disclosure in the relationship was predictive of whether the couple stayed together long term

It was found that self-disclosure in each partner was positively correlated with intimacy levels

Furthermore, less intimate couples rarely engaged in self-disclosure

Asked ppts in long-term marriages to write daily diary entries involving disclosure and intimacy

Research investigating the strength of the theory with gay and lesbian ppts totally supported the theory

This would explain why couples counselling is successful in saving long-term relationships from break down

The extensive self-disclosure that partners work towards during the course of therapy would explain why it's so valuable in preventing marriage/relationship breakdown

Researchers found that there were cultural variations in willingness to disclose certain types of info - particularly those relating to sexual intimacy/history

Partners from Western cultures tend to disclose freely of such info, but it is rarely shared in collectivist cultures like China

Cross-cultural research by Tang (2013) highlights that self-disclosure theory may be culturally biassed

Field of desirables - people you'd actually consider having a relationship with

We may filter out people of a certain religion, social class, education level because they would be too different to us

Geographical location, social class, education level, ethnicity, religion etc.

The outcome of all this filtering is homogamy whereby you form a relationship with someone who is socially and culturally similar

It is easier to find things in common with these people, making them more attractive

In the first 18 months of a relationship, it is important to establish that both partners have the same attitudes, beliefs and values

This lays a foundation for a successful future and promotes self-disclosure

When similarities in values aren't shared by both partners, relationships are likely to break down

Two partners complement each other when they have traits that the other lacks

Patience vs impatience, nurturing vs being nurtured, organised vs passive

This concerns the ability of each partner to meet the other's needs

Complementarity is key in the success of the relationship enduring

The authors assume that students in relationships over 18 months are more committed and had a deeper relationship

Derived from a single study into long (over 18 months) and short term (under 18 months) student relationships

This isn't objective and hasn't been replicated experimentally making it incredibly unscientific

Research has shown that when partners are in committed relationships they become more similar and develop shared attitudes and beliefs

The direction of cause and effect is a huge issue in this theory, which assumes that we choose people who already have similar attitudes and beliefs to us, resulting in a successful relationship

This theory was produced in 1962 and the authors would've been blown away had they realised that you could filter out any undesirable characteristics with a click of a button

Online dating has reduced the importance of certain variables, making it possible to communicate and bond with people who would have not been in the field of availables

Online profiles allow us to judge all 3 levels before we have met the partner and render any timeline useless

Psychologists argue that the real value in this filtering process is the fact that it stops people wasting time on relationships that will break down, so they can invest in a positive relationship

Filtering stops people making the wrong choice and having to live with the consequences

Dijkstra and Barelds (2008) found that 760 ppts they surveyed were more concerned with having a partner with the same needs, not complementary ones

If the rewards outweigh the costs, we stay but if not, we don't maintain the relationship

Each partner attempts to maximise their rewards and minimise their costs

A relationship is based on a series of exchanges between individuals

Bargaining - the couple costs out the relationship and identifies the sources of profit and loss

Commitment - the couple settles into a relationship, the exchange of rewards becomes relatively predictable

Sampling - the couple explores the rewards and costs in a variety of relationships

Institutionalisation - the interactions are established, the couple have settled down

We compare the costs and rewards in our current relationship with the costs and rewards we have experienced in past relationships or to friends' relationships

If the current relationship compares favourably, we are motivated to stay in the relationship

We compare the costs and rewards in our current relationship to what we think we would get with another partner or from being on our own

If our current relationship doesn't compare favourably to this alternative, we will end the relationship

Someone with low self-esteem will be satisfied with little profit and will perceive alternative choices as unlikely to be an improvement

Self-esteem becomes an additional factor influencing cost/benefit analysis and isn't something initially considered

In the communal couple, individuals are more worried about the other's needs and happiness above their own

Only in the exchange couple is there the score keeping predicted by SET

Clark and Mills (2011) identified 2 different types of couples; the communal couple and the exchange couple

The existence of the communal couple doesn't support the theory

Couples therapy aims to increase the number of positive exchanges between partners and decrease negative ones

The success of couples counselling can be used to assess the validity of this theory

Christensen (2004) found in a study of 60 couples that after therapy 66% reported sig. improvement as a direct result of an increase in positive exchanges

Individual differences in our perception of what constitutes a cost and a benefit, hindering the application of the theory

One huge benefit might be spending time getting to know the other's family but that could be a major con for someone else

Although many of the central assumptions of SET were supported by research, it became clear that for most people, profit is less important than fairness

The SET was modified in several respects, resulting in the Equity Theory