Catherine Salmon, Charles Crawford, Laura Dane, & Oonagh Zuberbier

Tiffany Hong & Alex Poh

Anorexic Behavior

Involves a combination of:Maintained body weight less than 85%

normal for age and heightIntense fear of fatnessExcessive exercise and/or food restrictionIncorrect view of oneself as fatAmenorrhea (lack of a menstrual cycle)

Evolutionary Rationale Eating disorders like anorexia are

ancestrally evolved adaptations for exerting control over reproduction

Based on 2 biological conceptsAdaptive reproductive suppression

○ Reproduction = costly, therefore when facing unfavorable social or ecological conditions, inc. lifetime RS by delaying reproduction until situation or ability to deal with it improves

Critical fat hypothesis ○ Positive relationship: female body fat &

menstruation and ovulation Ancestral times, adjusting body fat= way of modulating

reproduction

Reproductive Suppression Hypothesis (RSH) The RSH is a mechanism that allows for

adjustment of female reproduction in response to socioecological conditionsReduces amount of body fat

Poor conditions signaled the need to postpone reproductionCan be either social or ecological

Reproductive Suppression Hypothesis (RSH) Adaptive Reproductive Suppression

Because reproduction is very costly for female mammals, conditions unfavorable for reproduction can increase her RS by waiting until conditions or the ability to deal with the poor conditions improve

Reproductive Suppression Hypothesis (RSH) Critical Fat Hypothesis

Shows a positive relationship between female body fat and likelihood of menstruation/ovulation

~22% body fat required to maintain ovulation

Excessive thinness leads to amenorrhea

Reproductive Suppression Hypothesis(RSH) RSH suggests that the desire for

thinness and dieting activate a mechanism that indicates a poor environment for reproductionCues may include

○ High levels of social competition between females

○ Stressful attention from undesirable males

Reproductive Suppression Hypothesis Today, women may experience these

cues from puberty onwardThey may be represented by:

○ Body image distortions○ Desire for thinness○ Certain attitudes toward food○ Amenorrhea○ Decreased interest in sexual relationships

RSH in the EEA

Possible conditions for delayed reproduction1. relatively good pregnancy outcome under

optimal social conditions2. little help in obtaining reproductive

resources for disadvantaged young girls3. a relatively low reproductive value4. First reproduction under poor conditions

results in long-term disadvantage to fecundity or survival

Predictions

1. The perceived level of female-female competition will impact young women’s Eating Disorders Inventory (EDI) scores, with higher levels of competition producing higher EDI scores.

2. Stressful male attention will produce higher EDI scores.

Predictions• 3. Greater fashion content in media

products will produce higher EDI scores.• 4. Increased levels of stress from various

sources will not produce as significant effects on EDI scores as stress from reproductive concerns.

• 5. Preexisting susceptibility to eating disorders exists and will make some women more prone than other women to develop anorexic-like behavior.

Methods

• Participants– Female undergraduate psychology students

– Study – 1:100 participants– 2: 83 participants– 3: 99 participants– 4: 88 participants– 5: 86 participants

– Average age: 21 +/- 4.3 yrs

Methods

• Read stories (either high or low stress versions)– Stress usually dealt with competition or

decreased access to resources

• Completed questionnaires– Susceptibility measure (SV) questionnaire

before each manipulation• Response should reflect their own feelings

– Dependent measure (DV) questionnaire• Response should reflect if they were the woman in the

story they had just read

Methods• Susceptibility Measure (SV)

– Risk of developing an eating disorder– Were measured on 3 subscales of the Eating

Disorders Inventory (EDI) on a scale from 0 meaning never to 3 meaning always• Ineffectiveness

– 10 questions such as “I feel inadequate”• Interpersonal Distrust

– 7 questions such as “I have trouble expressing my emotions to others”

• Interoceptive Awareness– 10 questions such as “I can clearly identify what emotion I am

feeling”– Subscale results divided participants into high or low

susceptibility groups

Methods• Dependent Variable (DV)• Were measured on 3 subscales of the

Eating Disorders Inventory (EDI) on a scale from 0 meaning never to 3 meaning always• Body-dissatisfaction

– 9 questions such as “I think my thighs are too large”• Drive-for-thinness

– 7 questions such as “I feel extremely guilty after overeating”

• Maturity-fears– 8 questions such as “The happiest time in life is when

you are a child”

Study 1Female Competition High stress condition

Competition for acceptance into high-status sororities○ Would increase status, popularity, and

involvement in desirable social activities

Low stress conditionAbsence of necessity for sororities

○ Could participate in clubs and social activities she wanted without the need to compete

Study 1Female Competition DV Results:

Mean scores significantly affected by competition:○ Body dissatisfaction (p<0.001)○ Drive for thinness (p<0.001)○ Maturity fears (p<0.001)○ Composite score of all 3 EDI DV subscales

(p<0.001)High stress conditions evoked higher

disordered eating behavior and attitudes than the low stress condition

Study 1Female Competition Susceptibility Results:

Mean scores were significantly affected:○ Drive for thinness (p<0.01)○ Maturity fears (p<0.01)○ Body dissatisfaction (p<0.05)○ Composite DV score (p<0.01)

High susceptibility group was more affected than the low susceptibility group

Study 1:Female Competition

Stress Susceptibility

Study 2Male Attention• High stress condition

– Woman walks by a group of men who stare suggestively at her• Men are described as being very undesirable

• Low stress condition– Woman walks by a group of men who are

friendly and polite• Men are described as either attractive or not

but behavior is not threatening as in the high stress condition

Study 2Male Attention DV Results:

Mean scores significantly affected by competition:○ Maturity fears (p<0.001)○ Composite score of all 3 EDI

DV subscales (p<0.01) Mean scores not significantly

affected by:○ Body dissatisfaction (p<0.2)○ Drive for thinness (p<0.2)

AGAIN: High stress male attention caused more disordered eating behaviors than the low stress male attention

Susceptibility Results: No significant impact

○ Higher susceptibility group was more affected than the low susceptibility group

Study 2: Male Attention

Stress Susceptibility

Study 3: Media

High stress conditionWoman works at a

university bookstore and is stocking (women’s) fashion magazines

Study 3: Media

Low stress conditionWoman works at a

university bookstore and is stocking international & national new publications

Study 3Media• DV Results:

– Mean scores significantly affected by competition:• Body dissatisfaction (p<0.01)• Drive for thinness (p<0.005)• Composite score of all 3 EDI DV subscales

(p<0.005)– Mean scores not significantly affected by:

• Maturity fears (p<0.02)• High-fashion magazines caused stronger

disordered eating behaviors and attitudes than low-fashion magazines

Study 3Media• Susceptibility Results:

– Mean scores were significantly affected:• Drive for thinness (p<0.01)• Maturity fears (p<0.01)• Composite DV score (p<0.005)

– Mean scores were not significantly affected by:• Body dissatisfaction (p<0.054)

• High susceptibility participants were more affected by fashion content than low susceptibility participants

Study 3:Media

Stress Susceptibility

Study 4Music & Gardening High stress conditions

Music exam is expected to be difficultTaking care of a garden is portrayed as

stressful

Low stress conditionsMusic exam is expect to be easyTaking care of a garden is portrayed as

relaxing

Study 4Music & Gardening• DV Results:

– Gardening mean scores significantly affected:• Body dissatisfaction (p<0.01)• Drive for thinness (p<0.001)• Maturity fears (p<0.01)• Composite score of all 3 EDI DV subscales (p<0.01)

– Music exam mean scores significantly affected:• Body dissatisfaction (p<0.001)• Drive for thinness (p<0.001)• Maturity fears (p<0.05)• Composite score of all 3 EDI DV subscales (p<0.001)

– High stress conditions evoked higher disordered eating behavior and attitudes than the low stress condition

Study 4Music & Gardening• Susceptibility Results:

– Gardening mean scores significantly affected:• Body dissatisfaction (p<0.01)• Drive for thinness (p<0.01)• Composite score of all 3 EDI DV subscales (p<0.01)

– Gardening mean scores not significantly affected:• Maturity fears (p<0.133)

– Music exam mean scores significantly affected:• Maturity fears (p<0.05)• Composite score of all 3 EDI DV subscales (p<0.05)

– Music exam mean scores not significantly affected:• Body dissatisfaction (p<0.09)• Drive for thinness (p<0.07)

• High stress conditions evoked higher disordered eating behavior and attitudes than the low stress condition

Study 4: Music & Gardening

Stress Susceptibility

Study 5Hospital High stress condition

Waiting at the hospital to hear about a badly injured best friend

Low stress conditionWaiting at the hospital to hear about a mildly

injured best friend

Study 5Hospital DV Results:

Mean scores significantly affected by competition:○ Body dissatisfaction (p<0.01)○ Drive for thinness (p<0.05)○ Maturity fears (p<0.001)○ Composite score of all 3 EDI DV subscales

(p<0.001)High stress conditions evoked higher

disordered eating behavior and attitudes than the low stress condition

Study 5Hospital Susceptibility Results:

Mean scores were significantly affected:○ Drive for thinness (p<0.05)○ Composite DV score (p<0.05)○ No maturity fears sub-score noted

Study 5: Hospital

Stress Susceptibility

Discussion• Hypotheses mostly confirmed

– Female competition produced higher EDI scores than no competition• Had the strongest effect of all

– Stressful male attention produced higher EDI scores than non-stressful male attention

– Strong fashion content produced higher EDI scores than weak fashion content

– Hard music exams produced higher EDI scores than easy music exams

– Stressful gardening produced higher EDI scores then relaxing gardening

– Serious injury to a friend produced higher EDI scores than minor injury to a friend

Discussion• Effect Sizes:

– Female Competition• 6.01

– Gardening• 4.53

– Hospital• 3.59

– Music• 3.53

– Male Attention• 2.75

– Media• 2.51

Discussion• Prediction 4 was not confirmed because

the female competition study had a stronger effect than the stressful male attention study.– Prediction 4 - Increased levels of stress from

various sources will not produce as significant effects on EDI scores as stress from reproductive concerns

• The reproductive suppression model is supported by the result that the female competition had the strongest effect.

Discussion

Interestingly, the media study produced the weakest effect. This contradicts the common assumption that the media is mostly responsible for eating disorders

It may be that the media does not provide cues to attractiveness but rather female competition

Discussion• Disturbing finding:

– It was very easy to manipulate participants’ EDI scores.• Stress in general seemed to increase EDI scores.

• Potential Problem:– All the studies involved social aspects.

• Social relationships and support are almost always key factors in reproductive suppression

– Asocial situations may have no impact of EDI scores.

• Susceptibility to stress was key to EDI scores– Those with higher stress tolerance would almost

always have significantly lower EDI scores than those with lower stress tolerance.