Neural Mechanisms in Eating Behaviour - Plan

Discuss neural mechanisms involves in the control of eating behaviour (8+16) - plan

• AO1 Homeostasis and the internal working environment - the time gap between eating and satiety.
• AO1 Reduction of glucose causes the message to lateral hypothalamus. 
• AO1 Seen as ‘eating centre’ and creates feeling of hunger.
• AO2 Anand and Brobeck 1951 - A lesion in the lateral hypothalamus led to a loss of feeding behaviour in rats known as aphagia. Electrical stimulation produced feeding 
• AO3 Use of rats and lab setting - high internal validity but struggling to generalise due to differences in rats and humans, despite similar brain structures. 

• AO1 Ghrelin released by lateral hypothalamus and human feels hungry and then seeks out and consumes food. 
• AO1 triggers response from ventromedial hypothalamus which sends message to stop eating 
• AO2 Hetherington and Ranson 1942 - Lesions in the VMH caused rats to overeat and become obese. 
• AO2 Damage to VMH has caused hyperphagia and obesity in many species, including humans. (although usually damage much be present in the paraventricular nucleus)
• AO3 much much applicable to humans sue to some studies being tested on them. Unecthical treatment of rats. 
• AO1 the feeling of satiety prevents overeating.

• AO1 Neuropeptide Y is sometimes seen as the neurotransmitter which could be responsible to overeating. 
• AO2 This could be seen as the (real-world-application) reason why people become obese - due to an overproduction of neuropeptide Y. 
• AO2 When rats were injected with neuropeptide Y, they became obese due to overeating. 
• AO2 however, Marie et al 2005 genetically modified rats without NPY and eating behaviour didn't change. 
• AO3 conflicting studies make results low in validity and hard to generalise. 

• AO1 also looked at is the role of the stomach and its contractions when hungry. 
• AO2 Canon and Washburn put balloon in stomach and witnessed more contractions of balloon when hungry. 

• AO3 IDAs - Use of animals - rats - similar brain structure, god control, not directly relatable with behaviour/biology, doesn't have implications like social pressures, immoral due to unethical treatment, speciesism, more ethical than using humans, cost-benefit analysis
• AO3 IDAs - Biological Approach - biology dictates choices, genes are the main contributing factor, no explanation of social pressures, doesn't explain association, links to ….
• AO3 IDAs - Determinism vs free will - biological impact of genes leaves no control, things like NPY can’t be altered, role of stomach is central to human biology and can’t be changed though this is debatable - gastric bands (real life applications?) 

Evolutionary Eating Behaviour - Plan

Evolutionary Theory of Eating Behaviour 

Factor 1: high calorie and meat 

AO1: Ancestors had to consume high calorie foods in the EEA for energy and store this for when food supply is low. This trait makes them survive and then passes on to offspring. 

AO2: Gibson and Wardle (2001) - presented 4-5 year olds with lots of vegetables and they chose the highest calorific ones - potatoes and bananas - showing no taste preference, just calories. 

AO3 Evaluation: Children are difficult to rely on - could have been texture, taste or familiarity that caused these children to choose the specific fruit and veg. 

AO1: Preference for meat comes from decline in quality of plants. Hunter-gatherer societies makes meat a faster option to feed everyone. The amino acids are essential in intelligence development - more intelligent survive and pass on trait. 

AO2: Milton (2008) - without animals, people could not have evolved into an intelligent species and meat allowed humans to gather all of the necessary nutrients they needed to survive. 

AO3 Evaluation: Cordain et al (2006) argued that early humans consumed most of their calories from plant materials and were vegetarians. 

IDAs: Psychology as a science - difficult to falsify. Evolutionary approach doesn't acknowledge cultural influences and why some cultures don't look at high calorie foods - makes it culture biased. 

Factor 2: Taste preference

AO1: Sweet foods - Sweet foods are often high calorie. Also associated with ripe fruit which was rare and therefore a treat. Sweet foods are usually not poisonous. 

AO2: Bell et al - sweet food given to Eskimos who don't usually have it and it was not rejected - sweet food preferred universally. Also found sweet receptors in tongue. 

AO3 Evaluation - Only tested on Eskimos - lacks population validity and doesn't necessarily mean that all cultures worldwide would accept sugar due to their different upbringing and adaptions, e.g. Thailand prefer spicy foods. 

AO1: Taste Aversion - bait shyness, avoiding foods that have become associated with being ill. 

AO2: Garcia (1955) - rats who were made ill by radiation avoided foods they’d been fed directly before becoming ill. 

AO3 Evaluation: The use of rats isn't generalisable to humans despite similar brain structure - they do not have the same social pressures, behaviour or intelligence that humans have. 

IDAs: Deterministic - people have no free will, everything is decided by adaptive traits developed by early ancestors. Also doesn't take into account the social impacts of eating behaviour, although does touch on the behavioural approach with the bait shyness due an association being made. Food preferences, however, can also be influenced by other people. 

Success/Failure of Dieting - Plan

Discuss factors into the success and failure of dieting (8+16 marks)

Factor 1: Failure

AO1: Restraint theory - restraint synonymous with dieting. 89% female population in UK restrain food intake at some point.

AO2: Herman and Mack (1975) - 15 participants, 3 conditions. Low-restraint eat less in condition 2 and 3 than zero. High-restraint eat more in conditions 2 and 3. Positive correlation between score on eating restraint questionnaire. High restraint = more eaten. (women)

AO3 Evaluation: Only 15 participants - low population validity and an inability to generalise results to a wider population. Also correlations do not prove cause and effect and mean reliability is affected. 

AO1: Boundary model - the dietary boundary between hunger and satiety leading to the ‘what-the-hell’ effect. Role of denial - denying food makes an individual crave them more. 

AO2: Wegner et al (1987) - Asked participants to not think about a white bear and ring bell if they did. Condition where told not to think about bear rang bell more. 

AO3 Evaluation: Instructions were very vague and inconclusive - lacks validity and reliability. 

IDAs: Gender bias: Most research conducted on women - different hormones and biology to men, as well as social pressures. 

Factor 2: Success

AO1: Motivation - important in success of dieting, usually more successful with more motivation, links to social support also. 

AO2: Lowe et al (2004) - Weight losses achieved through WeightWatchers were maintained over a five-year period and an average of 71.6% of people maintained a loss of 5% of body weight. 

AO3 Evaluation: Other contributing factors aren't considered - the type of diet could biologically work rather than it being due to social support. 

AO1: Detail - When people get into a routine, food becomes boring and same-ish. People need to focus on details of specific foods. 

AO2: Jelly Bean Experiment Redden -  135 people 22 jelly beans, one at a time, information given, 2 conditions. More specific detailed condition enjoyed experiment more. 

AO3 Evaluation: Doesn't necessarily explain eating behaviours, preferences etc. 

IDAs: Free Will - people voluntarily diet but are often expected to by society - does this affect the success/failure?

Attitudes to Food - Plan

Discuss factors influencing attitudes to food.

factor one - health

AO1 outline - Pressure to have a healthy balanced diet - link to Crohn’s and coeliac disease - limited on food choice which also links to convenience and the issues with the availability of food and links to cost also 

AO2/3 Research evidence linked to factors - Turila & Pangborn (1998) - questionnaire data - women’s consumption of dairy - actual consumption was based more on liking than on health concerns. 

Evaluation of research - Questionnaires - social desirability bias making results low in validity. Only focuses on women making it difficult to generalise to men. 

AO2/3 Research evidence - Rapoport (2003) - growing interests in healthy foods, but more people are eating out and the population is becoming heavier 

Evaluation of research - Doesn't really have any empirical data that can be analysed and results are very conflicting - reduces validity. 

IDA - Biological approach - focuses mainly on illnesses that can’t necessarily be prevented (excluding diabetes) which limits food choices. Arguable when it comes to available, cost, e.t.c. 

Links to determinism - health forces some people to make considered food choices. 

Factor two - learning 

AO1 outline - Operant conditioning from parents - eat vegetables to get dessert. Parental attitudes and preferences. Association and also social learning through media and image. 

AO2/3 - Birch and Malin (1982) - 2 year olds to new food over 6 weeks. 1 food presented 20 times, 1 five times and 1 was novel. Direct relationship between exposure and food preference. 8-10 exposures necessary to shift preference. supports neophobia. 

Evaluation - study on children make result limited to a certain age group and lower population validity. 

AO2/3 - Meyer and Gast (2008) - 10-12 year old boys and girls - found a positive correlation between peer influence and disordered eating. 

Evaluation - correlations do not establish cause and effect - lack in reliability and make results difficult to generalise. 

IDA - Nature vs nurture - doesn't take into consideration the nature/biological side of the approach (illnesses or genetic make up) focuses on upbringing and social influences. Also deterministic because of the social influences’ inability to be changed.