PSYCHOLOGY REVISION

Eating behaviour

* Attitudes to food and eating behaviour * Explanations for the success and failure of dieting * Neural mechanisms in eating behaviour

Cognitive development

* Paget’s theory of cognitive development * Vygotsky’s theory of cognitive development * Applications of cognitive developments theories to education
Relationships
* The formation of romantic relationships * The maintenance of romantic relationships * The breakdown of relationships * Sexual selection * Sex differences in parental investment * The influence of childhood on adult relationships * The influence of culture on romantic relationships

Discuss attitudes to food and/or eating behaviour (24 marks)

Social learning theory emphasises the impact that observing people has on our attitudes and behaviour.

As children's’ parents usually provide food for them, it seems obvious that parental attitudes to food will affect their children's attitudes to them. Children also learn what to eat by watching their parents. This can be explained by social learning theory. This occurs when children observe their parents eating. In this sense, the parents act as eating role models. Observing parents getting rewarded by enjoying eating certain foods, the children learn to imitate these food preferences as they expect to receive similar rewards by doing so. This theory would therefore argue that children should show similar preferences as their parents having learned these preferences from them through a process of vicarious learning.

There is a great deal of research support the SLT. For example, Brown and Ogden found consistent correlations between parents and their children in terms of snack food intake, eating motivations and body dissatisfaction. These findings show that observation in childhood in the home is a significant factor in determining eating behaviour and so parental attitudes and behaviour is therefore an essential part of the social learning process of food choice and eating behaviour.

However, it can be argued that the majority of eating behaviour can be learned alternative role models than just our parents. Meyer and Gast surveyed 10 - 12 year old girls and boys, and found a significant positive correlation between peer influence and disordered eating, especially when the ‘likeability’ of the peer was taken into account. This means that children are likely to imitate the behaviour of peers who are popular, and that often this means they are imitating disordered eating behaviour.

As well as parental modelling, the role of social learning is evident in the impact of television and other media on attitudes to eating. MacIntyre found that the media have a major impact both on what people eat, and also their attitudes to certain foods. Women who are successful and are thin encourages girls to believe that if a woman is thin, she is more likely to be successful. As well as the media having a negative impact on eating behaviour, it may also have a positive impact as it can teach people about healthy eating.

Another factor that has been shown to influence eating behaviour is mood. A great deal of research has focused on the relationship between our mood and subsequent food choices. It is generally accepted that food can be comforting when we are feeling down and that we associate certain foods with pleasurable feelings. Research has shown repeatedly that people who are stressed or of low mood do ‘comfort eat’ by increasing their carbohydrate and sugar intake. Further research has suggested a link between happy mood and more nutritious food.

There is research to support the idea that mood plays a key role in influencing eating behaviour. For example, Garg et al found that when 38 participants were offered either hot buttered popcorn or grapes as they watched either an upbeat comedy or sad film, the participants watching the sad film consumed 36% more popcorn whilst those watching the comedy consumed more groups. It was concluded that people feeling sad or depressed, however, just want to ‘jolt themselves out of the dumps’ with a quick indulgent snack that tastes good and gives them an immediate ‘bump of euphoria’

On the other hand, these studies can be argued as gender biased because research solely focuses on females. Most studies focus on body dissatisfaction and disorders in relation to women. However, studies have shown that homosexual men are more at risk of developing an eating disorder. This subculture promotes a lean, muscular body image, putting pressure on gay men to be ‘ideal’. Siever found that homosexual men have shown higher levels of body dissatisfaction and higher levels of dieting than women. This suggests that studies which are only carried out on women are providing a limited view of attitudes to food and eating behaviour

Eating behaviour: Discuss explanations for the success and failure of dieting (24 marks)
One explanation for the failure of dieting is the restraint theory proposed by Herman and Mack. It was developed as an attempt to explain both causes and consequences associated with cognitive restriction of food intake. The theory suggests that attempting not to eat ironically increases the probability of eating. People often fail because the dieter has periods of resistant followed by periods of disinhibition; a result of eating more than normal through loosening resistances.

In an attempt to explain why dieting might lead to overeating, the ‘boundary model’ states how hunger keeps intake of food above a certain minimum, and satiety prevents us from overeating. Between these two levels, psychological factors have the greatest impact on consumption. It appears that attempting not to eat can, paradoxically, increase the probability of overeating. In addition, restrained eaters have a self imposed desired intake. Once they have gone over this boundary they continue to eat until they reach satiety (beyond the maximum level imposed as a part of their diet).

Support for the claim that dietary restraint can lead to overeating comes from Wardle and Beales. They randomly assigned 27 obese women to either a diet group, an exercise group or a control group. Results in lab assessments showed that women in the diet condition ate more than the other women, implying that overeating is caused by dieting. However, the numbers in each condition of the independent groups design were small, limiting the representativeness of the sample.

Another explanation for the failure of dieting is the role of denial which suggests that attempting to deny a thought frequently has the opposite effect, making it even more prominent. For example, Wegner asked some participants not to think about a white bear, but to ring a bell if they did, and others to think about the bear. Results showed that those told not to think about the bear rang their bells far more often than participants instructed to think about the bear. Therefore as soon as food is denied, it becomes more attractive and likely to be eaten which ruins the diet. Diets often fail because when a restricted food becomes forbidden, the denied food becomes more attractive making attempts to suppress it difficult.

Research support comes from Soetens who divided participants into restrained and unrestrained eaters . This suggests that restrained eaters who tend to overeat try to suppress foods more often but end up thinking about it and wanting it. However, Soetens study used data from personal accounts of participants which suggests limitations on memory. Retrospective recall is never 100%, and this creates problems for the study's internal validity.

An explanation for the success of dieting is the role of detail, Redden suggests that successful dieting lies in the attention we pay to what is being eaten. He claims that people usually like experiences less as they repeat them. To overcome this, Redden suggests that instead of thinking ‘not another salad’, we should focus on the details of the meal (e.g. rocket, pomegranate etc. ). By focusing on the specific details of each meal, people get bored less easily and so are better able to maintain their diet.

To test this theory, Redden gave 135 people 22 jelly beans each, one at a time. As each bean was dispensed, information about it was flashed onto a computer screen. One group saw general information (bean number 8) and the other group saw specific flavour details (cherry flavour number 8). Participants enjoyed the task more if they saw the specific flavour details.

Much of the research on dieting involves women participants. This is also the case for research on obesity, as the majority of people who take part in interventions to promote weight loss are females. Therefore, research into eating behaviour is generally gender biased and so studies may be low in external validity and so research cannot be generalised to males.

Eating behaviour: Discuss neural mechanisms in eating behaviour (24 marks)
AO1: Homeostasis is the biological process involving neural mechanisms that detect the state of the environment inside the body and also correct it to restore that environment to its optimal state. The body has evolved two homeostatic mechanisms to regulate food intake which are both dependant on glucose levels. Hunger increases as glucose levels decrease. This decline activates the lateral hypothalamus resulting in the feeling of hunger. This causes the individual to search for and consume food, causing glucose levels to rise again. This then activates the ventromedial hypothalamus leading to the feeling of satiation.

Researchers discovered that damage to the lateral hypothalamus in rats caused a condition called aphagia. Researchers also found that stimulation of the LT elicits feeding behaviour. A neurotransmitter found in the hypothalamus, called neuropeptide Y is particularly important in turning on eating. When injected into the hypothalamus of rats, NPY causes them to immediately begin feeding even when satiated. Repeated injections of NPY into the hypothalamus of rats produced obesity in just a few days.

Similarly, another explanation of eating behavior is found with the ventromedial hypothalamus.
The ventro-medial hypothalamus (or VMH), is also very important also known as the “stop” switch. A rise in glucose levels and a decrease in grelin (hormone that is released from the stomach when there is no food in it) activates the ventromedial hypothalamus, which leads to feelings of satiation, which in turn inhibits further feeding.

AO2: Early researchers found that damage to the VMH result in obesity in a number of different species, including humans. However, Gold that lesions restricted to the VMH produced overeating. However, subsequent research has failed to replicate Golds findings.
The importance of the role of the hypothalamus has been replicated in further studies where the role of neurochemicals (neuropeptide Y ) has also been supported. Repeated injections of NPY into the hypothalamus of rats produces obesity in just a few days (Stanley ef al., 1986), which demonstrates the impact that this neurotransmitter has in eating behaviour.
Lutter (2008) has found supporting evidence for the role of ghrelin as being crucial in boosting appetite. He concluded that extra levels of ghrelin were produced in stressed individuals which caused them to overeat. However, it may be possible that other psychological processes were overlooked in this study (eg psychological impact of mood)

Piagets theory

AO1: Piaget believed that cognitive development was a result of two influences: maturation and the environment. Maturation refers to the effect of ageing. As children get older, certain mental operations become possible and at the same time, through interactions with the environment, their understanding of the world becomes more complex.

AO1: Schema are self-constructed mental structures that can be behavioural (grasping an object) or cognitive (classifying objects). Rather like individual computer programmes, schemas are ‘programmes’ that people construct for dealing with the world. When a child is born, it has few schemas, but these are developed over time as a consequence of the child's interaction with its environment.

AO1: Assimilation is when a child initially tries to understand any new information in terms of their existing knowledge of the world. For example, a baby who is given a new toy car may grasp or suck that toy in the same way that they grasped or sucked on a rattle. Assimilation occurs when an existing schema is used on a new object. Assimilation, therefore, involves the incorporation of new information into an existing schema. Accommodation occurs when a child adapts existing schema in order to understand new information that doesn’t appear to fit.

AO1: According to Piaget, cognitive development is driven by the need for equilibrium in cognitive structures. The child tries to reduce imbalances by developing new schema or adapting old ones until equilibrium is restored, a process Piaget called equilibration.

AO1: Piaget believed that children pass through a series of stages in the same order - they are invariant and that a child moves through the stages in a set order and never skips a stage.

AO1: The sensorimotor stage takes place from 0 - 2 years. Children learn about the world through their sense and actions, hence the name of the stage. Children are extremely egocentric, they are not able to differentiate themselves from others. From 8 months they begin to develop object permanence but this is not fully developed until the end of this stage.

AO1: The preoperational stage takes place from 2 - 7 years of age. Children's thought becomes increasingly symbolic as they begin to represent their world with words, images and drawings. They are, however, not capable of reversibility of thought.

AO2: Piaget’s ‘three mountain study’ demonstrates egocentrism. Children were placed in front of a model of three different mountains with a doll placed in another position and asked what the doll could see from the locations, A,B, C and D. Four year old children almost always chose their own perspective, rather than the perspective from the doll. Only 7 - 8 year olds could succeed. This shows the inability to step outside your own perspective and see things from another’s point of view.

AO1: With the concrete stage, children can now perform logical operations and can therefore reverse concepts. This is the most important change as they no longer judge only by appearances. However, children cannot deal with abstract concepts.

AO1: The formal operational stage takes place from 11 years and onwards. The individual can now deal with abstract situations, going beyond the realms of immediate reality. He or she can think in the abstract, especially in scientific thinking.

AO2: Piaget used the beaker problem to demonstrate how children apply logical thinking to problem solving. Children were shown five liquid beakers and asked to work out how to turn the liquid yellow by combining various liquids. Young children tried random combinations whereas children at the stage of formal operations developed a logical strategy.

AO3: Piaget’s theory combines nature with nurture to explain cognitive development. Piaget’s conception of nurture is more focused on the physical environment.

AO2: Piaget underestimated children’s abilities at younger ages and may have overestimated the ability to use abstract logic in the formal operational stage. In general, his theory focuses too much on logic and generally ignores social factors. A further criticism is that the methods he used to research children's behaviour were flawed. One issue is that Piaget’s studies involved children from European academic families who valued certain aspects of cognitive development, such as logical thinking.

AO2: However, despite the criticisms, Piaget remains one of the most influential psychologists. His theory has had an enormous influence on education and psychological research.

Vygotsky’s theory
AO1: The major theme of Vygotsky’s theory is that social interaction plays a fundamental role in cognitive development. Vygotsky believed that every aspect of a child’s cognitive development appears first at social level and later, at an individual level.
AO1: Vygotsky proposed that children are born with elementary mental functions, such as perception and memory. These are transformed into higher mental functions by the influence of culture. Lower mental functions are biological and a form of natural development. Higher mental functions are exclusively human. The role of culture is to transform elementary mental functions into higher mental functions.
AO2: Vygotsky proposed that higher mental functions were uniquely human. However, research over the past 20 years suggests that he was wrong. Savage et al taught several chimpanzees to use human language. The chimpanzees are exposed to the human culture around them and moved through their ZPD.
AO1: Through culture, children acquire much of the content of their thinking. The surrounding culture also provides a child with the processes of their thinking. In short, culture teaches children both what to think and how to think.
AO1: A child learns through problem – solving experiences shared with someone else, usually a parent or teacher but also peers. All people with greater knowledge are called experts. Initially, the person interacting with the child assumes most of the responsibility for guiding the problem – solving activity, but gradually this responsibility transfers to the child.
AO1: Vygotsky believed that children cannot be accelerated beyond their understanding but can move ahead a reasonable distance if given assistance. He used the expression zone of proximal development to refer to the area between the level pf performance a child can achieve and that which can be achieved by working with someone who has greater skills. According to Vygotsky, learning or cognitive development does not take place in the area of current development or does it take place too far ahead of what the child can do independently.
AO2: Evidence for the ZPD was produced in a study by McNaughton and Leyland. They observed young children working with their mothers on a jigsaw puzzle of increasing difficulty, and then a week later observed the children working on their own. The children reached a higher level of difficulty with their mothers than when they were on their own so defining their ZPD. Vygotsky predicted that the greatest teaching input will occur at the edge of ZPD at which the child can still cope.
AO1: According to Vygotsky, children learn little if left alone to struggle. What they require, and what most adults provide is scaffolding, which can be defined as the appropriate support framework for children’s learning
AO1: Vygotsky attached greater importance to language. In the early years, children talk to themselves while playing. He referred to this as private speech because it does not serve the function of communicating with others. Vygotsky believed that language is fundamental to the development of cognitive abilities because it serves two important functions. First, internalised language is through, second, it is the means by which ideas are communicated and received, thus increasing understanding.
AO2: Vygotsky claims about the effects of culture have been supported in cross – cultural research. Gredler found that in Papua New Guinea as an example of how culture can limit cognitive development, counting is done by starting on the thumb of one hand and going up the arm and down to the other fingers, ending up at 29. This system makes it very difficult to add and subtract large numbers; a limiting factor for development is culture.
AO2: Vygotsky’s theory is a more positive approach than Piagets because it offers ways that others can be actively involved in assisting a learner. In this way, Vygotsky’s theory may potentially have more educational application than Piaget’s theory.

The formation of romantic relationships
AO1: The reward / need satisfaction theory suggests that we are attracted to people who we find satisfying. Most stimuli in our lives can be viewed as being rewarding or punishing in some way and we are motivated to seek rewarding stimuli and avoid punishing stimuli. The sort of things we find rewarding are the need for company, financial security and an attractive partner. Mutual attraction occurs when each partner meets the other’s person’s needs.
Rewarding stimuli produce positive feelings in us and punishing stimuli produce negative feelings. Given that some of these stimuli are other people, it follows that some people make us happy and some do not. According to the principles of operant conditioning, we are likely to repeat any behaviour that leads to a desirable outcome and avoid behaviours that lead to undesirable outcomes. Byrne and Clore’s theory suggests therefore, that we enter into relationships because the presence of some individuals is directly associated with reinforcement (the person creates positive feelings in us) which makes them more attractive.
As well as liking people with whom we share a pleasant experience with, we also like people who are associated with pleasant events. If we meet someone when we are feeling happy, we are much more inclined to like them than if we meet them when we are feeling unhappy. Byrne and Clore believed that the balance of positive and negative feelings was crucial in relationship formation. Relationships where the positive feelings outweigh the negative feelings were more likely to develop and succeed, whereas, relationships where the negative feelings outweigh the positive feelings were likely to fail.
AO2: The theory proposes that we like some individuals because they provide direct reinforcement. Support for this claim comes from Griffit and Guay. Participants were evaluated on a creative task by an experimenter and then asked to rate how much they liked the experimenter. This rating was highest when the experimenter had positively evaluated the participants performance on the task.
Most of the studies carried out in this area are laboratory studies and therefore do not necessarily show that the principles of need satisfaction apply to real life, such studies lack mundane realism.
The reward / need satisfaction theory does not account for cultural and gender differences in the formation of relationships. For example, Lott suggests that in many cultures women are more focused on the needs of others rather than receiving reinforcement. This suggests that this theory is not a universal explanation of relationship formation and therefore culturally biased.
AO2: There is empirical evidence by Zajonc (1968) supporting the rewards and need for satisfaction theory. Zajonc conducted a lab experiment which predicted the more time spent with one another, the more one another liked each other. He found that the longer spent with someone the more they liked them and the more they found them psychically attracted.(C)This supports the theory's factor of close exposure being rewarding and as an explanation into the formation of a romantic relationship, and thus increasing the internal validity of the theory.

However the supporting empirical evidence from Zajonc can be criticised for containing a methodological flaw, as the experiment was conducted in an artificial environment as participants were introduced to strangers in a laboratory setting. This means that Zajoncs' findings cannot be applied to real life and thus reducing the ecological validity of the study. This furthermore reduces the internal validity of the theory as the empirical evidence acting as supporting evidence is weakened.

Discuss two theories of the maintenance of romantic relationships
Social exchange theory: Thibaut and Kelly
AO1: At the centre of this theory is that assumption that all social behaviour is a series of exchanges; individuals attempt to maximise their rewards and minimise their costs. In our society, people exchange resources with the expectation that they will earn a profit. Rewards that we may receive from a relationship include being cared for and sex. Costs may include effort, financial investment and time wasted. Rewards minus costs equal the outcome. Social exchange stresses that commitment to a relationship is dependent on the profitability of this outcome.
AO1: In order to judge whether one person offers something better or worse than we might expect from another, Thibaut and Kelly proposed that we develop a comparison level – a standard against which all our relationships are judged. Our comparison level is a product of our experiences in other relationships together with our general views of what we might expect from this exchange.
AO2: There is empirical evidence by Marelich et al (2008) supporting the social exchange theory. Marelich et al surveyed 267 students in the US and found men were more likely to use blatant lies to have sex with woman, whilst woman are likely to have sex to avoid confrontation. The findings show that both genders avoided costs (confrontation) to receive rewards (sex), which further shows that rewards are favoured in the maintenance of a romantic relationship. These findings support the theory in that the cost-rewards ratio is taken into account into the maintenance of a romantic relationship, and thus the internal validity of the theory is strengthened.

However the supporting empirical evidence by Marelich et al has been criticised for containing a methodological flaw. Marelich et al surveyed 267 students in the US only and so the study can be said to be cultural bias as findings can now not be generalised to romantic relationships, other than those of the US culture. This therefore reduces the population validity of study and furthermore also weakens the internal validity of the theory as it acts as supporting evidence.
AO2: The theory has been criticised by some psychologists for being deterministic as research shows that the theory fails to explain the role of free will in that some couples maintain their romantic relationship out of love and care rather than the cost-reward ratio
AO1: Another theory acting as an explanation for the maintenance of romantic relationships is the equity theory. The theory suggests that the most important feature into the maintenance of a romantic relationship is perceived to be the fairness between partners, by counting costs and benefits. These costs and benefits of the relationship can be unprofitable and the relationship can still be maintained, as long as it is perceived as fair by each partner and the cost-reward ratio remains the same. If the cost-reward ratio was to change a partner who finds it most unfair will become dissatisfied and may choose to end the romantic relationship
AO2: There is empirical evidence by Van Yperen & Buunk (1990) supporting the equity theory. Van Yperen & Buunk conducted a longitudinal study with a sample of 259 couples who had been gathered from an advert in a local paper (86% of which were married) who obtained a score for equity in the relationship using the Hatfields' Global Measurement of Satisfaction. Van Yperen & Buunk found that those who had found their relationship equitable a year previously now were most satisfied whilst those who under-benefited a year previously were now least satisfied. These findings show that those who felt the relationship was most fair, a year later was the most satisfied and so supports the theorys suggestion of that the most important feature into the maintenance of a romantic relationship is the fairness between partners and thus increases the internal validity of the equity theory as an explanation into the maintenance of romantic relationships.

However the supporting empirical evidence by Van Yperen & Buunk has been criticised for containing a methodological flaw. Van Yperen & Buunk conducted a longitudinal study were there sample had to obtain a score for equity in the relationship using the Hatfields' Global Measurement of Satisfaction questionnaire. Using a self-report the study is prone to social desirability with participants wanting to be looked at in the best light. This disrupts the findings of the study as its possible that the findings did not measure what they had set out too ( the importance of fairness) and thus reduces the internal validity of the study. Furthermore acting as supporting empirical evidence as it is now weakened, the internal validity of the theory is also weakened.
AO2: The theory has been criticised by psychologists for being deterministic, in ignoring the role of free will of individuals by suggesting that we only take into account the fairness of our relationship when maintaining it and ignores our individual choices or other factors
AO2: The equity model seems to explain maintenance and breakdown of western relationships, but is less effective in collectivist non-western cultures or in cultures where the freedom to leave a relationship is limited by laws and social norms. These economic theories are ethnocentric and an etic analysis or an attempt to apply them in other cultures would be inappropriate.

The breakdown of relationships
AO1: There are a range of theories overlooking the breakdown of romantic relationships. One being Ducks theory of relationship dissolution (ToRD), which explains the breakdown of romantic relationships through four stages. The first stage; intra-psychic phase: refers to where feelings are expressed between the partners and they discuss plans to save the relationship. The second stage; the dyadic stage: refers to where the partners assess the others behaviour in order to evaluate the costs of withdrawing from the relationship. The third stage; social phase: refers to where the partners engage in getting over activities and publicly announce the break-up. The final stage; grave-dressing: refers to where each partner questions their decision and then consider how the break-up has impacted their social network.
AO2: There is empirical evidence by Tashiro & Frazier (2003) supporting Ducks ToRD. Tashiro & Frazier surveyed undergraduates who had recently broken up with their partners. It was found that they reported emotional distress and personal growth. Through grave dressing processes they were able to put the relationship to rest.(C) Findings suggested that the breakdown of romantic relationships is broken down into stages like Duck's theory suggests. Findings also suggested just like Ducks theory that grave dressing was the last stage of the breakdown of a romantic relationship. Supporting the theory, the study improves the theory’s internal validity.
However supporting empirical evidence by Tashiro & Frazier can be criticised for containing a methodological flaw. By containing the sample of undergraduate students the study is criticised for being sample bias, as findings cannot be generalised to relationships other than those of undergraduate students. This reduces the population validity of the study, and further the internal validity of the theory as the study acting as supporting evidence has just been weakened.
AO2: The theory has been criticised by some psychologists for being deterministic. The theory suggests that breakdown of romantic relationships is the result of four liner stages, but fails to take into account any other factors such as choice of breaking up and how we act after the break-up. The theory therefore ignores the role of free will and fails to consider for the breakdown of all romantic relationships as it is unlikely that all breakdown of relationships occur through the four linear stages. This furthermore reduces the external reliability of the theory.
AO2: Psychologists have however praised the theory for being intuitively appealing. The theory makes logical sense in suggesting that people experience different emotions and behaviour during a breakdown. With the theory taking into consider individual differences it can be applied to breakdowns in every-day life and thus increased the external validity of the theory.

Sexual selection
AO1: Psychologists suggest that there is a relationship between human sexual selection and reproductive success. Explaining this relationship there is intra-sexual selection and inter-sexual selection. Intra-sexual selection suggests that members of the same sex compete with each other in order to get a member of the opposite sex and ensure reproductive success. The winner mates and then passes on their genes. Whichever traits led to their success i.e. health because there genes are stronger, will be passed onto the next generation (the offspring) through their genes. This is known as male competition as they fight for women with certain traits i.e. an hourglass figure because they are more fertile/ young age because of their reproductive ability.

Inter-sexual selection suggests that members of one sex will be attracted to the opposite sex if they possess certain qualities i.e. power because they can offer more resources to ensure survival for offspring. This is known as female choice as the females choose the male on offer most powerful the opportunity to mate, as she feels this will increase the rate of reproductive success.
There is supporting empirical evidence by Singh (1993) into the relationship between human sexual selection and reproductive success. Singh found that although breast size, weight and physique varied over the years of beauty winners, a consistent feature was a small waist set against full hips. This suggests that the waist to hip ratio may symbolise fertility as this is a quality men find attractive and look for in women when choosing their partner. This supports the theory of that there is a relationship between human sexual selection and reproductive success as it supports the intra-sexual selection explanation of that men look for certain traits in order to ensure reproductive success. By supporting the theory, this increased its internal validity.

There is a second piece of supporting empirical evidence by Swami & Furnham (2006), that found that the optimum waist to hip ratio of 0:7:1 closely corresponds to supermodels. Just like Singh, it was found that the waist to hip ratio was an attractive quality in women for men. This improves the internal reliability of the theory that there is a relationship between human sexual selection and reproductive success as the same results were found by Singh and Swami & Furnham.
However both pieces of supporting empirical evidence by Singh and Swami & Furnham contain a methodological flaw. Both studies measure mate preference as opposed to actual choice as it takes into account our desires only which we will not all gain. Therefore the findings of the study do not set out to measure what we had actually hoped to (the relationship between human sexual selection and reproductive success) and thus decreased the internal validity of both studies. This furthermore reduces the internal validity of the theory as both pieces of its supporting empirical evidences have been weakened by methodological flaws

Parental investment
AO1: Human females make a greater biological investment than males, because females have far fewer egg cells and egg cells are far more costly to produce than sperm cells. Another reason why females have a greater initial investment because females can only have a limited number of offspring, whereas, males can have a much larger number of children.
As well as this, females must make a postnatal investment. Human females are consequently burdened with the extended period of childcare. This is another reason why parental investment is high in females.
The greater investment of females may also be explained in terms of parental certainty. This is because females are always certain that the child is theirs, as fertilisation is internal. On the other hand, the male is under pressure to protect themselves from investing resources in a child who may not be theirs.
Also, sexual jealousy may have evolved as a solution for sexual infidelity. Men are more jealous of the sexual act, whereas, women are more jealous in a shift of emotional focus.
AO2: Evidence that parental investment by males is an evolutionary behaviour comes from comparative studies. Such research has found that in both chimpanzees and bonobos males show little or no parental investment. This suggests that male parental investment is an evolutionary change through our ancestors.
However, some psychologists view the evolutionary approach as limited and suggest that personal and social factors determine male behaviour. These factors include the quality of the relationship with the mother. Evidence for this is that childhood experiences such as divorce tend to correlate with the degree to which men invest.
A consequence of the sex differences in parental investment is that some women attempt greater parental investment by cuckolding their parents. The benefits may include financial stability and high quality genes. However, risks of this may include abandonment or violence from the females current partner.
Because men are liable to be unsure of their childs paternity, they rely on the childs resemblance of themselves. Daly and Wilson recorded conservations in a maternity ward and found that mothers often tried to strengthen the bond between father and son by commenting on similarities suggesting an increased confidence in their childs paternity which increases child investment.
This theory of parental investment would predict that parental investment would be greater if fathers know that the child is biologically theirs as they would be reluctant to spent time and money on a child that is not theres. However, Anderson found that men invested no more resources in their biological children than in their step children.
A physiological approach can be used to explain the differential costs of parental investment among males and females. A study by Geher et al found that males had greater arousal of the automic nervous system than females when presented with examples that show the cost of parenting.

The influence of childhood on adult relationships

The influence of culture on romantic relationships
AO1: Relationships in Western and non – Western cultures differ in the degree to which they are voluntary or non – voluntary. Western cultures generally have a high degree of social mobility, allowing frequent interaction with a large number of people and so a high degree of choice in romantic relationships. Non – western cultures have less social mobility, therefore less choice about whom they interact with.
Cultures also differ in the degree to which relationships reflect interests of the individual. In individualistic cultures, individual interest are more important and romantic relationships are more likely to be based on love. In collectivistic cultures, relationships are more likely to reflect the interests of the family.
Cultures differ greatly in terms of norms that apply to the development of romantic relationships. These norms act as guidelines for appropriate behaviour within a culture. For example, Ma studied self – disclosure in internet relationships and found that American students self – disocled sooner than East Asiana students.

AO2: There is empirical evidence by Moore and Leung supporting the theory. It was found that when studying on a group of 106 collectivist students (Chinese students) and a group of 212 individualistic students (Australian students) 61% of the individualistic students were in a romantic relationship in comparison to just 38% of collectivist students being in a romantic relationship. With findings showing that there more romantic relationships in the individualistic culture, it supports the theory’s suggestion of that there are relationship differences in cultures and thus increases the internal validity of the theory.

However the supporting empirical evidence by Moore and Leung (2001) has been criticised for containing a methodological flaw. Moore and Leung contained a sample of almost double the amount of students from the individualist culture than the collectivist culture which means that the sample used was not fair and thus neither will the findings be. Findings therefore are weakened by not taking into account this sample issue and the internal validity of the study is also weakened. Furthermore by acting as supporting evidence the weakened study has now weakened the internal validity of the theory also.

The theory contains opposing empirical evidence by Pinker (2008). Pinker found that romantic love is evolved to promote survival and reproduction among human beings, and thus considered love to be human universal. Pinker suggests that romantic relationships are a form of an evolutionary process and I universal, and thus occurs in every type of culture. Pink therefore opposes the theory’s idea of that romantic relationships differ between different cultures and thus decreases the theory’s internal validity.

The theory contains a further piece of supporting empirical evidence by Gutah & Singh (1982). Gutah & Singh found that love marriages reported feelings of happiness in the early stages of their relationship, yet depleted overtime, whilst those in arranged marriages reported low levels of love in the early stages which increased overtime. Findings covered both cultures of the collectivist culture (arranged marriage) and the individualistic culture (love marriages) and found that there were differences within the romantic relationships of the two different cultures. This therefore supports the theories of idea of that relationships differ between cultures and thus the internal validity of the theory is strengthened.

Psychologists propose that the theory can be criticised for failing to consider the role of nature. As research has shown that romantic love can be considered as human universal and thus evident in all relationships within cross cultures to promote survival and reproduction, the theory can be criticised for failing to consider this. This decreases the internal validity of the theory as human universal love has evidenced that there are no differences in relationships between cultures.