EATING BEHAVIOUR

To read up on eating behaviour, refer to pages of 189–199 of Eysenck’s A2 Level Psychology.

Ask yourself

  • What is the strangest food you have eaten?
  • How does food differ across cultures?
  • How might health concerns affect eating behaviour?
  • What is comfort eating?

What you need to know

FACTORS INFLUENCING ATTITUDES TO FOOD AND EATING BEHAVIOUR / EXPLANATIONS FOR THE SUCCESS OR FAILURE OF DIETING
  • The effect of culture, mood, and health on attitudes to food and eating disorders
/
  • Operant conditioning
  • Biological explanations
  • Self-delusion

Factors Influencing Attitudes to Food and Eating Behaviour
Culture

There are many variations in food eaten across cultures and so learning plays a large role in eating behaviour. For example, to Hindus the cow is a sacred animal and so to them beef is not a food. And Jews have religious laws forbidding them to eat pork or shellfish, so these are not counted as food items.

THEORIES/RESEARCH EVIDENCE FOR CULTURAL FACTORS
  • Classical and operant conditioning, as well as social learning, are the learning processes by which culture affects our food choices. Babies will be weaned on to the type of food their parents eat, and so therefore will not only associate those tastes with eating, but will be praised for eating up and so positively reinforced. Children will also model their parents’ eating habits. Social influence from peers, advertisements, and the media is also likely to add to or alter the food schemas that have been constructed, and this could continue throughout life.
  • People also construct schemas of what is and is not food, based on cultural norms. For example, British soldiers in the Second World War, on reaching Russia, were given caviar but said that “fish jam” was not what they thought of as food. Similarly, most British people might baulk at crispy fried insects or stewed ducks’ feet, both of which are considered delicacies in other cultures!
  • Eating behaviour also varies between sub-cultural groups. This can include the timing and frequency of meals, the size and type of meal, and the eating crockery and cutlery. So whether you have a proper meal at lunchtime or in the evening; eat supper at 6 p.m. or, as traditional Spaniards do, at 11 p.m.; whether you use plates or bowls, a fork, a knife and fork, or chopsticks; these variations are the norm in some environments and not in others.
EVALUATION OF CULTURAL FACTORS
  • Strong evidence. There is a wide range of evidence showing a clear link between culture and eating behaviour.
  • Cause and effect. The research evidence on culture and eating uses the natural experimental method where culture is a naturally occurring IV. This means cause and effect cannot be established and so only associations between culture and eating can be made.
Mood

Many people crave sweet or starchy foods (carbohydrates) when they are feeling low; this is the so-called comfort eating, and shows how a low mood can increase the amount of food consumed. The opposite of this, a decrease in eating, can occur as a result of an anxious or elated mood.
Psychological explanations: Learning theory can explain the effect of mood on eating through classical conditioning, and the learned association between the natural high and the eating of chocolate or other comfort food. Or operant conditioning can explain it because the feelings of happiness or pleasure when eating act as positive reinforcement. Social learning may also play a part because in our own society giving or receiving chocolate as a reward is a social norm.

RESEARCH EVIDENCE OF MOOD AS A FACTOR
  • Carbohydrates are linked to increased mood because they lead to an increase in serotonin, one of the brain’s neurotransmitters sometimes called the “happy” chemical because it is associated with raised mood, which would explain the comfort-eating behaviour. Laboratory studies have shown that a high carbohydrate diet increases the rate at which tryptophan enters the brain, and this is a precursor of serotonin.
  • The food with the greatest positive effect on mood is chocolate; people report chocolate as helping their mood when they feel emotionally low (Benton & Donohoe, 1999, see A2 Level Psychology page 192). The mood improvement is not the result of the carbohydrate in chocolate, as it also contains protein. The chemicals in chocolate that could affect brain function, such as anandamines, caffeine, phenylethylamine, and magnesium, are in such small quantities that they are unlikely to have any real effect on mood. This is supported by the fact that other foods have greater quantities of these chemicals and they do not seem to improve mood. So this leads to the conclusion that eating chocolate is in itself pleasurable because of the scent, taste and texture, which means endorphins are released in the brain, and it is these chemicals that lift mood and give an increased sense of well-being
  • Parker, Parker, and Brotchie’s (2006, see A2 Level Psychology page 192) meta-analysis of a wide range of research into eating behaviour, chocolate, and mood contradicts the above findings because they found no significant empirical evidence for chocolate as a mood-enhancing food. They concluded that chocolate gives emotional pleasure because it satisfies certain cravings but it does not have a lasting effect on improving mood. The pleasure is transient and caused mainly by the “melt-in-the-mouth” smoothness of the chocolate.
  • Caffeine is another food substance linked to mood. In Western industrialised culture it is very common for people to start the day with a caffeine “kick”. This is usually a drink with enough caffeine in it to make the person feel energised, more alert, and positive. Smith et al. (2003 see A2 Level Psychology page 193) found that two cups of normal strength coffee increased mood, alertness and concentration, general task performance, and memory. They also suggest a cause for this cognitive improvement, in that caffeine helps to maintain levels of noradrenaline centrally.
  • Neurotransmitter balance seems to be linked to mood and eating behaviour, and this can explain the over- or under-eating associated with mood disorders such as depression. Heath et al. (2006, see A2 Level Psychology page 193) have found that levels of serotonin (5-HT) and noradrenaline (NA) actually alter taste perception; raised levels of 5-HT and/or NA make food seem tastier, and lower levels of 5-HT and/or NA, as found in mood disorders such as depression, would make food less tasty. Thus, depressives may eat more because they are searching for the tastiness food used to have or they may eat less because of its lack of taste. This link between neurotransmitters, mood, and eating behaviour could also explain why many people eat less when really happy or when they are anxious.
EVALUATION OF MOOD AS A FACTOR
  • Tryptophan uptake is limited. Even a small amount of protein prevents the increased uptake of tryptophan and so would not increase serotonin levels; as little as 2–4% of the meal’s calories as protein would have this effect. This means the link between carbohydrates and increased mood is not as clear-cut as an increase in the uptake of tryptophan, as protein is also likely to be eaten at the same time and this prevents the reuptake of tryptophan.
  • Biochemical theory lacks validity. The biochemical theory of the effect of chocolate on mood is challenged because the amount of these chemicals in chocolate is low; other foods have higher levels and are not associated with improved mood.
  • Usefulness of the findings. The greater understanding the findings on the link between neurotransmitters, mood, and eating behaviour offer into mood disorders such as depression means the findings are of great value.
Health Concerns

In recent years a number of health issues have arisen such as the healthy diet, safety of food additives such as colourings, and the inherent goodness of the food itself such as food produced without use of chemicals or hormones.

RESEARCH EVIDENCE ON HEALTH CONCERNS
  • A UK government study (Food Standards Agency, 2007, see A2 Level Psychology page 194) of nearly 900 children found 58% of the sample aged 7 to 16 years had no serious food concerns, however, 42% were concerned about food-related diseases and illness such as bird flu (in the media at the time of the survey), the fat, sugar and salt content of food, and risk of food poisoning. Around 95% said that eating healthy food would make them healthy, and 82% agreed that eating healthily was personally important; 79% obtained healthy eating information from school and 31% from family or friends. The vast majority were aware that they should eat five portions of fruit and vegetables a day to stay healthy, and most were trying to cut down on sugary or fatty foods and sugary, fizzy drinks.
  • As the evaluation below shows, children’s concerns about food are not necessarily translated into their behaviour, as they may be concerned about healthy eating but not practise it. This may be in part due to the fact that a lot of advertisements for sugary and fatty snacks are colourful and designed to appeal to children by associating fun with the unhealthy food. Also, attractive models are often used and so social learning will also be involved.
  • The Food Standards Agency (2008, see A2 Level Psychology page 194) reports that the number of UK people aware of the benefits of eating five portions of fruit and vegetables a day rose from about 43% in 2000 to 58% in 2004, and sales of fruit and vegetables have also increased this century.
  • Health concerns about the use of pesticides and the fact that 4.5 billion litres are used annually (BBC, 2008) has led to a growth in the organic farming market. Organic farming increases the nutritional value of potatoes, carrots, and milk. This could explain why people are buying more organic food even though it is more expensive, as the sales grew by 22% between 2004 and 2005, and sales of boxes of organic vegetables increased by 53% in the same time period.
  • Garcia’s classic studies in the 1950s and 1960s have shown how one-trial learning can be linked to health. The original studies were based on the effects of radiation, including nausea. Rats learned an aversion to sweetened water (something they ordinarily have a strong preference for) when it was consumed before being irradiated. The rats learned this association through classical conditioning in one single trial, whereas usually classical conditioning takes many trials. This became known as the Garcia effect and explains how children may learn to avoid foods that might have harmful effects, for example foods that have made them feel sick. The one-trial learning is an adaptive or protective mechanism; the learning is so powerful that sometimes even the thought of that substance, let alone the sight or smell, is enough to make the child feel queasy.
EVALUATION OF RESEARCH EVIDENCE ON HEALTH CONCERNS
  • Contradictory data. The data from the government’s children survey does not seem to match the data on childhood obesity, which states that 27% of children in the UK are overweight (BBC, 2006, see A2 Level Psychology page 194) and 13.7% are clinically obese (Jotangia et al., 2005, see A2 Level Psychology page 194).
  • Self-report data. The UK government study findings are just self-report. What the children report they are worried about may not be reflected in their behaviour, i.e. in the foods they actually eat!
  • Socioeconomic factors. Obesity is far more common in lower socioeconomic groups, which suggests that socioeconomic factors might be relevant. These could include poorer access to educational resources for the parents so that norms for meals and snacks include a reliance on high-calorie, low-nutrient foods that are satisfying and cheap.
  • Lack of reliability. The actual percentages of people who say they do eat five portions of fruit or vegetables daily being 25% in 2000 and 50% in 2004 do not quite match those of the Food Standards Agency, and so there is a lack of reliability. This mismatch could be because fruit is quite expensive and many people do not enjoy eating vegetables. There is also the association between eating meat as a sign of self-worth and success because it is more expensive than vegetables, so eating meat could represent a reward for one’s work and effort.
  • Organic food is only a small proportion of food bought. The actual amount of organic food chosen is small compared to the total amount bought nationally.
  • The Garcia effect. This does have face validity: we do often avoid foods that have made us ill. However, this is not always the case, as anyone who has been sick on a particular form of alcohol and then continued to drink it can testify!
Explanations for the success or failure of dieting

Britain has an adult obesity problem as four times as many people are now classed as obese as were 25 years ago: 22% of adults are considered obese and 75% overweight (Lopez-Jimenez, 2008, see A2 Level Psychology page 195).
A diet usually refers to a lower calorie intake than normal. The general view is that dieting to lose weight may succeed in the short term, but the lost weight often returns in the long term. A number of aims can inspire the diet: the ideal of slimness being attractive and youthful, as well as healthy, and so the possibility of a longer lifespan.

Operant conditioning

Learning theory provides an explanation for the success or failure of dieting. Operant conditioning could positively reinforce dieting behaviour and weight loss if the weight loss is successful, so this would encourage the dieting behaviour to be repeated. On the other hand, if the diet did not result in weight loss this would be seen as punishing. Feelings of hunger would also provide punishment and so if punishment outweighed rewards then the dieting behaviour would be stamped out.

EVALUATION OF OPERANT CONDITIONING
  • Face validity. The strength of operant conditioning is that it offers a simple explanation that does seems to account for the success and failure of dieting.
  • Reductionism. A key weakness of operant conditioning is that it only considers environmental factors (nurture) and so ignores the biological factors, for which there is strong evidence.
  • Ignores cognition. A key weakness of operant conditioning is that it ignores the role of cognition because it is not observable and measurable and so is considered unworthy of study. This is a key weakness because clearly thoughts and expectations play a major role in dieting.
Biological Explanations

Mark (2006, see A2 Level Psychology page 196) argues that the reason diets fail is less to do with environmental factors and more to do with biological reasons, such as an imbalance of the hormone leptin, which has a role in regulating appetite. Bellar and Jarosz (2008, see A2 Level Psychology page 196) offer a further biological explanation. They point to the fact that blood sugar levels are imbalanced in the overweight as they have developed an insensitivity to the hormone insulin, which would normally regulate blood sugar levels, and this insensitivity has to be addressed to lose weight. For the diet to be successful, the dieter needs to develop insulin sensitivity, and to achieve this the dieter needs to exercise regularly as well as eat fewer calories. The weight loss is more permanent if the weight is lost gradually.

EVALUATION OF BIOLOGICAL EXPLANATIONS
  • Strong empirical support for the role of leptin. Havel (2000, see A2 Level Psychology page 196) has outlined the action of leptin on various hypothalamic areas that influence feeding behaviour and energy expenditure. Leptin seems to inhibit the release of another neurochemical, neuropeptide Y, which is the neurotransmitter stimulating hunger and eating behaviour. A low-calorie diet leads to low levels of leptin and this is why such diets seem to produce the increased sensations of hunger, and consequently weight may be regained. Weigle et al.’s (2003, see A2 Level Psychology page 196) study also found that a low-calorie diet results in low levels of leptin so it increases hunger, which leads to subsequent weight gain.
  • Contradictory evidence. Contradicting the leptin explanation is that obese individuals usually have high levels of leptin, which should mean they have small appetites and are not overweight.
  • Further explanation. Laposky et al. (2007, see A2 Level Psychology page 196) provide a further explanation that obesity is linked, probably genetically, to leptin resistance. This means obesity may be due to an abnormal leptin regulation system, which makes obese people insensitive to leptin and its signals to eat less. This would explain why they are obese in the first place, and why dieting is not successful in long-term weight loss.
  • Research applications. This means that there is the possibility of drug treatment or gene therapy in the future to regularise the physiological leptin system and therefore reduce obesity.
  • Dieting may not be good for you. Contradicting the positive effects of dieting, a Finnish study (The Guardian, 2005, see A2 Level Psychology pages 196–197) showed that although dieting and losing weight reduces the risk of heart disease and diabetes, it can lead to physiological damage, which can lead to long-term health risks of dying young.
  • Reductionism. The biological explanation is reductionist because it focuses solely on biological factors and ignores psychological factors. Truby et al.'s (2006, see A2 Level Psychology page 197) study for the BBC programme “Diet Trials” showed psychological factors, such as initial and quite fast weight loss, are highly motivating and so provide positive reinforcement (operant conditioning). Also, the need for social support when weight loss slows down is important. It is likely that the knowledge of media interest, even in the majority of participants who were not going to be filmed for the television programme, also acts as encouragement to stay motivated.
  • Social factors. de Castro and de Castro (1989, see A2 Level Psychology page 197) found the quantity of food eaten by an individual varies in direct proportion with the number of people present, i.e. we eat less when more people are present. This shows the role that social factors can play in eating behaviour.
  • Exercise plus diet is better than diet alone. Miller et al.’s (1997, see A2 Level Psychology page 197) meta-analysis of diet, exercise, and diet plus exercise weight-loss programmes found that the long-term success rate was greater for the diet plus exercise cohort.
Self-delusion

Self-delusion is another factor that may account for the failure of diets. Lichtman et al. (1992, see A2 Level Psychology pages 197–198) found that dieters delude themselves about both their food intake and exercise levels. Obese people on a reduced-calorie diet underestimated their food intake by 47% and also over-estimated the amount of exercise they took by 51%. This can clearly explain their failure to lose weight!