Ancestral Mechanisms in Modern Environments

1. Catherine Salmon, Charles Crawford, Laura Dane, & Oonagh Zuberbier Tiffany Hong & Alex Poh Ancestral Mechanisms in Modern Environments

2. Anorexic Behavior • Involves a combination of: • Maintained body weight less than 85% normal for age and height • Intense fear of fatness • Excessive exercise and/or food restriction • Incorrect view of oneself as fat • Amenorrhea (lack of a menstrual cycle)

4. Evolutionary Rationale • Eating disorders like anorexia are ancestrally evolved adaptations for exerting control over reproduction • Based on 2 biological concepts • Adaptive 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

5. Reproductive Suppression Hypothesis (RSH) • The RSH is a mechanism that allows for adjustment of female reproduction in response to socioecological conditions • Reduces amount of body fat • Poor conditions signaled the need to postpone reproduction • Can be either social or ecological

6. 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

7. 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

8. Reproductive Suppression Hypothesis(RSH) • RSH suggests that the desire for thinness and dieting activate a mechanism that indicates a poor environment for reproduction • Cues may include • High levels of social competition between females • Stressful attention from undesirable males

9. Reproductive Suppression Hypothesis • Today, women may experience these cues from puberty onward • They may be represented by: • Body image distortions • Desire for thinness • Certain attitudes toward food • Amenorrhea • Decreased interest in sexual relationships

10. RSH in the EEA • Possible conditions for delayed reproduction • 1. relatively good pregnancy outcome under optimal social conditions • 2. little help in obtaining reproductive resources for disadvantaged young girls • 3. a relatively low reproductive value • 4. First reproduction under poor conditions results in long-term disadvantage to fecundity or survival

11. 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.

12. 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.

13. 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

14. 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

15. 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

16. 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”

17. 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 condition • Absence of necessity for sororities • Could participate in clubs and social activities she wanted without the need to compete

18. 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

19. 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

20. Study 1:Female Competition Stress Susceptibility

21. 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

22. 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

23. Study 2: Male Attention Stress Susceptibility

24. Study 3: Media • High stress condition • Woman works at a university bookstore and is stocking (women’s) fashion magazines

25. Study 3: Media • Low stress condition • Woman works at a university bookstore and is stocking international & national new publications

26. 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

27. 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

28. Study 3:Media Stress Susceptibility

29. Study 4Music & Gardening • High stress conditions • Music exam is expected to be difficult • Taking care of a garden is portrayed as stressful • Low stress conditions • Music exam is expect to be easy • Taking care of a garden is portrayed as relaxing

30. 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

31. 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

32. Study 4: Music & Gardening Stress Susceptibility

33. Study 5Hospital • High stress condition • Waiting at the hospital to hear about a badly injured best friend • Low stress condition • Waiting at the hospital to hear about a mildly injured best friend

34. 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

35. 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

36. Study 5: Hospital Stress Susceptibility

37. 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

38. Discussion • Effect Sizes: • Female Competition • 6.01 • Gardening • 4.53 • Hospital • 3.59 • Music • 3.53 • Male Attention • 2.75 • Media • 2.51

39. 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.

40. 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

41. 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.