Eating behaviour AQA A Level Psychology

• Environment of Evolutionary Adaptiveness (EEA)


  The environment a species evolved in
• Early human diets


  • Dependent on environment and the foods that were available
• Preference for fatty/high calorie food

  Adaptive for early humans as a source of energy - e.g. meat and glucose
• Preference for sugar


  Evolutionary purpose - sugar/glucose = high energy food. New borns can distinguish between different sugars - they have a preference for fructose, which is particularly sugary. Our ancestors would have favoured foods, like fruit, that are high in sugars.
• Preference for salt


  Salt = essential for cell functioning. A preference is developed around 4 months old. Infants aged 16-25 weeks who had been breast fed (there is little salt in breast milk) preferred salted cereal - suggests this preference is innate as they had not learnt to prefer salt.
• Preference for fat


  High calorie foods, such as fat, were not readily available to our evolutionary ancestors. Learning to prefer high calorie foods was an adaptive advantage for our ancestors as these foods provide energy for survival. Fat contains twice as many calories as carbs and protein.
• Neophobia


  Humans have an innate unwillingness to eat new or unfamiliar foods. Food neophobia is most pronounced in childhood - 2-6 years old. Untried foods could be harmful and dangerous so neophobia is adaptive - it stops humans from consuming substances that could cause sickness or illness. Neophobia diminishes once we learn that specific foods will not poison us or cause illness.
• Taste aversion


  The development of taste aversions - helped our ancestors to survive. Humans, through natural selection, are genetically hardwired to learn taste aversions. Such aversions are very hard to shift - an adaptive quality designed for survival. There are certain tastes and smells that we avoid in order to avoid sickness/poisoning. If our ancestors were lucky enough to eat a poisonous food and survive - quickly learned not to make the same mistake again. Learning through association/conditioning.
• The best way to predict which fruit and vegetables would be preferred by 4-5 year old children - they would be chosen based on how dense they were in calories. The children preferred bananas and potatoes - they are calorie rich foods, compared to the sweet fruits that they did not choose.
• New-born babies (only 1-3 days old) demonstrated innate preference for sweet-tasting food and rejected bitter tasting substances.
• The evolutionary explanation takes a biologically reductionist approach to understating eating behaviour and food preference. Eating behaviour, food preference and neophobia are very complex behaviours and by reducing eating down to just evolutionary influences we do not consider the other factors involved in eating. Culture, social influence, cognition and personal experience will all influence our eating behaviour and food choices - not simply evolutionary drives. Therefore taking a more holistic approach could be better for validly explaining and understanding eating behaviour and food choices.
• A thiamine deficient rat acquired a preference for a distinctive flavour that was presented to it, followed by an injection of thiamine.
• Participants who had the bitter taste receptor gene hTASR38 rated the bitterness of vegetables containing glucosinolates (toxic in high doses) as 60% more bitter than those participants who did not have the bitter gene.
• Classical conditioning


  1. Flavour-flavour learning

  2. Develop a preference for a new food by associating it with a flavour we already like

  3. Due to innate preference for sweetness, we can learn to like foods by sweetening them

  4. Eventually learn to like these foods on their own
• Operant conditioning


  1. Children are directly reinforced for their food preferences by parents and older siblings

  2. Provide reward for eating certain foods, e.g. praise, encouragement and punishment

  3. Difficult to establish a preference in children for foods like green veg using rewards, classical conditioning is more powerful
• Social learning theory


  • Children acquire food preferences of role models they observe eating certain foods (observation and imitation)
  • Develops through indirect reinforcement - if the model appears to be rewarded and if they are someone the child identifies with
  • Has an adaptive purpose
• Family influences


  • Parents are a child's main role model from a young age, can have strong influence on attitudes children learn and develop towards food
  • If a mother dislikes a specific food and reacts negatively, child will observe and imitate this
• Peer influences


  • Peers, particularly in childhood, can influence preference for food
  • Birch (1980) study showed children changed their food preference more when placed next to children with different preferences
• Media influences


  • As children grow up, models outside of the family become more important, e.g. people in adverts, celebrities, social figures
  • Adverts for unhealthy foods can be appealing to young children, young female celebrities on fad diets can be appealing to young women
• Cultural influences


  • One of the most reliable predictors of food preference, especially with family eating patterns
  • We learn around the family table when, what and how much to eat, cultural rules of food preference are learned early
• Cultural norms


  • Ideals and norms within a culture can influence food preference and choice, e.g. what contributes to a "proper meal"
  • Older generation sees an ideal meal including meat and veg, common meal on a Sunday is a roast dinner
• Meat-eating


  • In Britain and France there is a tradition to eat all parts of an animal, which is why offal is common, this is less common in the USA where there is a strong aversion to offal
• Culture + learning


  = food preference
• The foods that parents present to their children, through cultural traditions, is influenced by flavour-flavour conditioning and vicarious reinforcement. The foods that we enjoy as adults are usually associated with happy and safe feelings from childhood.
• Brown and Ogden (2004) found consistent correlations between parent and children in terms of snack food intake, eating motivations and body dissatisfactions.
• Ogden (2007) found a significant correlation between parents, specifically mothers, diet and that of the child. Mothers dissatisfied with their own body shape are likely to pass this on to their daughters through social learning.
• Kotler et al (2012) Experiment 1: Children were more likely to indicate a preference for one food over another when one was associated with TV characters with whom they were familiar. However, when children were asked to choose between a healthy food with a favoured character and a sugary or salty snack with an unfamiliar one, this effect did not happen.
• Kotler et al (2012) Experiment 2: Children were more willing to try more pieces of a healthy food if a favoured character, in comparison with an unknown character, is promoting that food.
• A 2003 study found that for every 2 hours a person spends in front of the TV each day, the risk for obesity increases by 23%.
• MacIntyre 1998 found that the media have a major impact both on what people eat, and attitudes towards food.
• Dixon (2007) found that heavier TV use with more TV commercial viewing were associated with more positive attitudes towards junk food and heavier TV use was also independently associated with higher reported junk food consumption. They also found that ads for nutritious foods promoted selected positive attitudes and beliefs concerning these foods – therefore changing food advertisements could help reinforce healthy eating in children.
• A big change in western society has been the increasing availability of food outside the home, accompanied by a decline in family mealtimes and cooking. 46% of spending on food in the USA goes on food eaten in places other than the home. American adolescents eat up to 30% of their meals outside of the home, half of them in fast food restaurants.
• Social psychology presumes that people are a product of their social environment, with very little consideration given to cognitive or biological processes.
• The nature vs nurture approach assumes that all eating behaviours are determined by our key social models, without considering emotion or individual desire/motivation. It also does not consider evolutionary explanations for food preferences.
• Most studies on eating behaviour and attitudes focus on women, particularly when considering body dissatisfaction. Siever (1994) found that homosexuality is a risk factor in men for developing disordered eating attitudes and behaviours, but this gender bias is not apparent in much of the research supporting the social learning approach.
• Dual centre hypothesis


  The body has two separate systems – turning eating on and turning eating off
• Glucose levels decrease


  Hunger increases
• Glucose levels decrease


  Activates the lateral hypothalamus, people search for food and eat
• Glucose levels rise


  Activates the ventromedial hypothalamus, results in feelings of satiation, further feeding is inhibited
• Neuropeptide Y (NPY)


  Neurotransmitter produced by the lateral hypothalamus that is responsible for producing the feeling of hunger which motivates us to eat