Eating behaviour textbook

• Preference for sweetness


  Indicates high energy food

  Steiner showed that infants can distinguish between different types of sugar

  Menella showed that children who preffered sweeter foods grew taller
• Preference for salt

  An innate preference that appears at 4 months

  Harris found that breastfed babies preferred salted cereal despite not being exposed to salt
• Preference for fat

  Fat is high in calories, so became an advantage because it was an efficient energy source

  Fat increases palatability of foods
• Neophobia


  An adaptive fear of new foods that helps us to avoid foods that may be harmful, especially as we become more independent
• Taste aversion


  Seligman suggested idea of biological preparedness

  Being able to quickly learn an aversion to harmful foods is adaptive and can increase survival changes

  Garcia found that rats could quickly develop taste aversion to poison in order to survive
• Torres and Nowson suggested we prefer high fat foods when we are stressed to fuel fight or flight response
• Alcock suggested that our food preferences are determined by gut microbes which benefit from the nutrients we consume.
• Drewnowski suggested that some people are insensitive to bitter tasting chemical but this may be adaptive because bitter tastes are linked to anti-cancer foods. Shows taste aversions have individual differences
• Neophobia is maladaptive as food is now safer than ever but neophobia still limits variety of diet
• Cashdan suggested culture plays an important role in determining food preferences which is ignored by evolutionary explanation
• Classical conditioning


  Preferences for new foods develop because of association with taste we already like, which explains why we often sweeten new foods
• Operant conditioning


  Parents reinforce food preferences by directly rewarding children when they eat, e.g, with pudding after eating vegetables
• Social influences


  Social learning theory suggests that family, peers and TV all model eating behaviours and give the child direct and indirect reinforcement.

  Birch placed children next to peers with different food preferences, and the children's preferences changed to be more similar to their peers
• Cultural influences


  Rozin suggested culture/ethnicity is the most reliable predictor of food preference as we learn cultural norms of preference within the family
• Little evidence that 'flavour-flavour' learning leads to food preferences
• Hare-Bruun showed that social learning effects of TV on unhealthy food preferences was very weak after 6 years, and peers became more influential
• Jansen and Tenney showed how children preferred energy-dense drink when modelled by a teacher
• Eating behaviour in Western culture has changed dramatically over the last few decades.

  46% of food spending in America is on external food sources
• The role of the hypothalamus


  Regulates level of blood glucose within narrow boundaries by adjusting secretion of insulin and anti-insulin hormones
• Lateral hypothalamus (LH)


  'Feeding centre' activated when glucose levels drop.

  Creates hunger and motivation to eat when released with neuropeptide Y
• Ventromedial hypothalamus (VMH)


  'Satiety centre' activated when glucose levels rise.

  Inhibits LH and creates feeling of fullness
• The role of ghrelin


  An appetite stimulating hormone secreted by the stomach, detected by the arcuate nucleus of the hypothalamus and closely asscoiated with feelings of hunger
• The role of leptin


  An appetite-suppressing hormone secreted by adipose cells involved in satiety mechanisms and cessation of eating
• Hetherington and Ranson showed that lesions to VMH in rats caused hyperphagia and obesity. Lesions to LH caused aphagia and starvation
• Valassi suggested that there are many biological contributors to eating behaviour such as hormone CCK, serotonin and dopamine
• Woods suggested that the glucostatic mechanism was only important in severe energy deprivation and that otherwise, social and cultural factors are more influential
• Much of the research is on rats and other animals, so findings are difficult to generalise to human behaviour and therefore have low ecological validity
• A better understanding of neuronal and hormonal mechanisms controlling eating behaviour can have therapeutic benefits for both anorexia and obesity
• Family systems theory for anorexia

  A psychodynamic explanation suggested by Minuchin that views dysfunctional family interaction as a major factor in the development and maintenance of anorexia made up of:

  Enmeshment

  Overprotectiveness

  Rigidity

  Conflict avoidance

  Autonomy and control
• Enmeshment


  Family members self identities are tied up with one another. Poorly defined roles and over-involvement leads to refusal to eat as an assertion of independence
• Overprotectiveness


  Family members reinforce loyalty and dependence by nurturing one another obsessively and self-sacrificing
• Rigidity


  Stress produces a crisis and family cannot adapt. Child's attempt at independence are thwarted
• Conflict avoidance


  Family members take all steps to avoid discussion of problems until crisis point
• Autonomy and control


  Bruch suggested AN sufferer strives to assert their independence against domineering parent by starving themselves
• Brockmeyer found that AN patients showed significantly greater desire to be autonomous.

  Strauss and Ryan showed AN patients had greater disturbances of autonomy
• Aragona suggested that enmeshment is difficult to measure and operationalise so research findings are inconsistent
• Robin suggested Behavioural Family Systems Therapy was effective in treating AN, but the study was not blinded and is therefore unreliable
• Family dysfunction may be the result of having an AN sufferer in the family, not the cause
• Family systems theory can explain AN in females and adolescence, but not in males or at other ages
• Social learning theory


  A way of explaining behaviour that includes both direct and indirect reinforcement, combining learning theory with the role of cognitive factors, uses:

  Modelling

  Vicarious reinforcement

  Role of the media