Etiology of Bulimia

What are the factors which contribute to people developing bulimia?

Biological level of analysis

Strober (2000) found that first-degree relatives of bulimia sufferers are 10 times more likely than average to develop bulimia.

Biological level of analysisKendler et al (1991) studied 2000 female twins

Concordance rate of 23% for MZ and 9% for DZ twins for eating disorders.

What does this mean?

Biological level of analysis

Can you think of any limitations of using self-reporting as a means of gathering data on eating disorders?

Biological level of analysisThere is a link between eating disorders and

the genes responsible for the production of serotonin.

There is low serotonin activity in many sufferers of eating disorders.

Which other disorder is also linked to low serotonin activity?

Weight set pointThere is a theory that every individual has a

weight set point.

What do you think this might be?

Weight set pointThere is a theory that every individual has a

weight set point.

What do you think this might be?

The weight level that a person is predisposed to maintain, controlled in part by the hypothalamus.

(Remember Hetherington & Ranson?)

Evaluation of the biological LoA Research does indicate a biological difference between people with ED and without.

The anti depressant drug treatment is shown as successful. (reduces the effect of serotonin)

HOWEVER

*Can not distinguish cause from effect!!

*Very small samples are used in research.

*No one bio mechanism has been pinpointed for ED.

*Cant account for why eating disorders have increased vastly in the past 30 years.

*Not a 100% concordance rate in bulimia with twins.

Cognitive level of analysisThe body-image distortion hypothesis

(Bruch 1962)

Cognitive level of analysisSlade & Brodie (1994)

Reformulated the body-image distortion hypothesis

Sufferers of eating disorders are in fact uncertain about their size and shape

And when compelled to make a judgement, tend to overestimate their size

Fallon & Rozin (1985)American undergraduates asked

Which figure is most like you

Is most like your ideal shape

Is most like the figure that the opposite sex find attractive

Polivy & Herman (1985)Cognitive disinhibition

Dichotomous thinking (all or nothing)

Bulimics follow very strict dieting rules, when they break them they tend to binge eat.

Dieters and non-dieters took part in a ‘taste test’

Given a milkshake before being asked to taste 3 types of ice-cream (told to eat as much as they liked)

Dieters ate more than non-dieters

Cognitive level of analysisEvaluation

Describes rather than explains

Distorted eating patterns may affect distorted thinking patterns rather than the other way around

Sociocultural level of analysisDo ideals of beauty change over history?

In what way?

How about between cultures?

Media’s Influence:Internet Videos

What types of messages about appearance are communicated through magazines, advertisements, movies, and TV shows?

http://www.dove.us/#/features/videos/videogallery.aspx/

Media

Other PeopleWhat negative messages about our bodies do

we receive from parents, friends, coaches, teachers and others?

Childhood teasing, particularly by peers Loved ones disapprove or criticize Coaches make suggestions to improve

performance Indirect comments by parents and friends

Cultural Expectations In some cultures a rounder figure is the ideal whereas in

others a slim build is considered beautiful.

If our bodies do not match the cultural expectation of where we live, we may strive to make our body look like the ideal. This may lead to unhealthy eating and exercising practices.

Barbie ®

Her waist is the same diameter as her head.

Her neck is twice as long as an average human’s.

Her legs are 50% longer than her arms. (On average they would be 20% longer.)

She is 35 lbs underweight.

International Journal of Eating Disorders, 1995

Ken ®

Compared to an average-sized maleHeight is +51 cmWaist is +25 cmChest is +28 cmNeck is +20 cm

(International Journal of Eating Disorders, 1995)

Action figures such as Superman and Spiderman are always depicted with exaggerated muscles.

Heroes on video games are usually “big, strong, and powerful”.

Body dissatisfaction is the strongest predictor of risk for developing an eating disorder!

Influence of the media How much influence does

the media have on our idea of how we should look?

How could research be conducted to find out the effects of the media on body image?

Influence of the media How much influence does

the media have on our idea of how we should look?

How could research be conducted to find out the effects of the media on body image?

Now read pages 223-224 of ‘Levels of Analysis in Psychology’

Course Companion Read (or reread) p162 –

165 of the Course Companion.

Make detailed notes on the three levels of analysis in relation to the etiology of bulimia.

Do a detailed yellow study sheet on Jaeger et al’s 2002 study.