whr and self body image

WHR and Self Body Image

• Significant issues with body image

• Body shape role in mate choice

• Both sexes awareness of WHR issues

• Is WHR specifically involved in self body judgments?

Joiner, Schmidt & Singh (1994)

• Depression

• Limited earlier work on WHR and body dissatisfaction

• Body dissatisfaction had been connected to depression, bulimia, eating disorder

Subjects

• Undergraduates

• Questionnaires– Beck Depression Inventory (BDI)

• BMI, WHR, anthropometric indicies

Findings: Just WHR

• Low WHR corresponds to higher body dissatisfaction

• Agreement with Radke-Sharpe et al. (1990)– Large hips and buttocks --> higher body

dissatisfaction

Findings: Interaction• WHR x BDI x Gender interaction

• Body dissatisfaction more complicated

Cognitive Theories of Depression

• Depressive distortion– Misrepresent own self shape

• Depressive realism– Better/more accurate representation of self

shape

Sexual Dimorphism Identification

• Results fit better with depressive realism

• Depressed people better at perceiving the reality of what their WHRs convey

• Depressed males will be dissatisfied with low WHRs (more gynoid)

• Depressed females will be more dissatisfied with high WHRs (more android)

WHR as Adaptation

• Additional evidence for WHR playing role in mate choice for some time

• Involvement with other psychological constructs

Focused Attention

• Individuals can identify desired sexually selected characteristics in others and self

• Predict that you would draw attention to traits if beneficial

Singh & Bronstad (1997)

• Body scarification

• Standard Cross-Cultural Sample (SCCS)– 186 societies– Assess pathogen prevalence, polygyny, degree

and location of body scarification in population– Can’t be used to determine individual specifics

Sex. Selection & Parasites

• Positive correlations between amount of societal scarification and pathogen prevalence

• Females more likely to scarify their stomachs and breasts at higher pathogen levels

If You’ve Got It, Flaunt It…

• High pathogen levels --> overall reduction in potential mates

• Much more important to select genotypically fit, healthy mates

• Scarification of sexually dimorphic secondary sexual traits draws attention to them

• Highlights fitness

www.ezakwantu.com/Scarifacation%20Abdoman%2002.jpgwww.ezakwantu.com/Scarifacation%20Abdoman%2011.jpgwww.ezakwantu.com/Scarification%20Face%2006.jpg

Navel Gazing

• Female scarification of stomach fits with WHR interpretation

• Navel is indicator of natural waistline• Woman who draws attention to desired WHR may

gain attention of higher quality males• Other non-scarification ornamentation used to

similar purpose– Corsets, belts, shawls, etc.

Henss (1995)• Replicated and expanded Singh’s studies• Methodology changes• Between subjects design

– Avoid demand characteristics– Each subject only saw and evaluated one figure

• Big Five personality factors– Extraversion, agreeableness, conscientiousness,

emotional stability, intellect

• In all, 51 criteria subjects are assessing on• 72 males, 72 females, Germany

Agreement with Singh

• Effects of body weight are considerably stronger than those of body shape

• Underweight and normal rated more attractive

• Overweight least attractive, but most emotionally stable, family oriented, agreeable, and conscientious

Differences from Singh

• WHR 0.8 most attractive (then 0.7)

• Underweight more attractive than normal weight

Attractiveness

• Singh: “attractive” and “sexy”

• Henss: weighted composite of 51 scales– Ran collapsed analysis of 15 scales– Still U>N>O, whereas Singh had N>U>O, but

closer

• May also be a difference in the within- vs. between-subject design

Overall

• General agreement with Singh’s findings

• Some quibbling over particulars

• Body weight and body shape being used in attractiveness judgments

Furnham, Tan & McManus (1997)

• Singh’s ranked data strictly non-parametric; parametric data more powerful

• Used ratings (7 pt. Likert scale) instead of ranking

• Participants judged all figures; within-subject

• British subjects

Broad Results

• Attractiveness: N>U>O

• Healthiness: N>O>U

• Youthfulness: U>N>O

• Overall, WHRs of 0.7 or 0.8 rated most favourably for all factors, regardless of weight

Compare and Contrast

• Unlike Henss (1995), but like Singh, none of the underweight figures considered most attractive

• Normal weight figures rated highest for everything but youthfulness

• Across weights, high WHRs rated unattractive, unhealthy, and unyouthful

• Like Henss, WHR of 0.8 rated most attractive

Contribution

• Generally agrees with Singh

• Along with Henss, identifying body weight as more significant than body shape in judgments

• Still arguing for WHR as adaptive trait in mate choice

• Is it first-pass filter, though?

Universiality?

• By 1997 still general support for WHR

• American (Caucasian, Mexican, Black), Indonesian, German, British subjects sampled

• But what about non-industrialized?

Yu & Shepard (1998)

• Yomybato: Matsigenka indigenous people in Manu Park, Peru– Slash and burn agriculture, hunting and gathering– About 300 people in population– Extremely non-Westernized

• Shipetiari: Matsigenka people living outside Manu Park– More exposed to Western culture

• Alto Madre: ethnically mixed population of Amarakaeri, Huachipaeri, and Piro– Even more Westernized

Method

• Singh’s figures

• Used U7, N7, O7 and U9, N9, O9 figures

• Males asked to rank figures from most to least for beauty, health, and marriage preference

Results

• Yomybato and Shipetiari– Grouped figures by weight first, then WHR– Preferred overweight figures– High WHR more healthy

• Shipetiari– Low WHR figures more attractive and desirable as

spouses– Didn’t consider healthiest to be most attractive or

desirable– “…suggesting that WHR preferences may be changing.”

(321)

• Alto Madre– Didn’t differ significantly from American

judgments– Grouped figures by WHR first, then weight– N7 generally ranked highest– Low WHR figures always ranked higher than

high WHR figures

Nurturist Account• Argue that Singh’s results are due to

Western media• Least Westernized of tribal peoples showed

most difference from American population• “…many ‘cross-cultural’ tests in

evolutionary psychology may have only reflected the pervasiveness of western media.” (322)

• But, no explanation of why Western media would favour low WHRs

In Small Populations

• With small population sizes, limited mate choices– Few people, kinship, etc.

• Individuals would have detailed knowledge of health history of potential mates from long-term personal contact

• Physical features may take on secondary role in mate choice

Wetsman & Marlowe (1999)

• Hadza of Tanzania• Mixed savanna, woodland environment• Small population of only 1000 individuals• 1/3 exclusively hunter/gatherer

– Only used males form this group for the study

• Hunger not uncommon, but no one can remember anyone ever starving

• No one obese

Method

• U7, N7, O7 and U9, N9, O9

• Forced choice for attractiveness, health, preference for wife

• 75 men (18-68 years, mean 37)

• Also, American undergrads (24 subjects, mean age 21.2)

Results

• American undergrads– Same pattern as Singh’s earlier studies

• Hadza– No significant preference based on WHRs– Used body weight– Strong preference for overweight, then normal,

than underweight for all criteria

Environment Input

• Suggests WHR a second-pass filter, not first-pass

• Propose differing environmental input model

• Food scarcity determines hierarchy of selection

In Food Scarce Environments

• Best option is to use body weight• Survival first, reproduction second• If WHR used first, most attractive,

healthiest females may starve before reproducing or never achieve enough fat to be able to reproduce

• Even if higher weight conferred some health detriments, higher fat stores preferred– None of Hadza are obese

In Food Rich Environments

• Risk of starvation low

• WHR better predictor

• Here too much weight can compromise reproductive fitness

Marlowe & Wetsman (2001)

• Hadza (and American) males

• Asked about: attractiveness, health, desirability for wife

• New set of figures• Did not vary in weight• Broader range of

WHRs

Results

• Americans disliked WHR of 0.9 and 1.0 and also 0.4 and 0.5; general preference for WHRs around 0.7

• Hadza preferred higher WHRs (0.8, 0.9, 1.0 all ranked above 0.7)

Concordances

• Measure of agreement among subjects

• Americans: greater concordances for attractiveness and desirability to marry

• Hadza: greater concordance for health

• For Hadza health determines desirability for marriage; for Americans it is attractiveness

Confound

• Even with no weight variation, Hadza still preferring high WHR

• Artifact of preference for heavier women• BMI confounded with WHR in Singh’s

original figures and with current figures– Height is kept constant; as WHR increases from

0.4 to 1.0, so would weight in a real woman– Females with larger waists look heavier

Theorizing

• Environmental differences

• Current fertility status

• Different female body shapes

Environment

• Among foragers, thinness probably indicates poorer health (parasites)

• Women who are too thin are energetically stressed• Will interfere with reproduction• High energy demands on Hadza women• Prior to agriculture health-threatening obesity

probably very rare• Should have been preference for women with

more fat stores

Developed Nations

• Propose agriculture led to more predictable and surplus food supply (at least for some)

• Risk of obesity increased

• Men developed preference for low BMIs (and WHRs)

Fertility Status• Pregnant women have high WHR• Total fertility (TFR): average number of

children produced by a woman in a society• American TFR = 2.1; Hadza TFR = 6.2• High WHR (pregnant?)

– American: bad mate choice (probably only one more child with her)

– Hadza: not so bad (up to another 5.2 children)

• The lower the TFR the more men favoured for attending to signs of non-pregnancy

Different Female Body Shapes

• Different populations of humans

• Geographical isolation; different phenotypic expressions; fat stores

• Health risks of 2D WHR presumed to correlate with “real WHR” measure in 3D

• But, two women can have same frontal WHRs, but different actual WHRs

Marlowe, Apicella & Reed (2005)

• Actual WHR = measurement with tape measure

• Frontal WHR = 2D front view

• Profile WHR = 2D profile (side) view

• Frontal WHR doesn’t reflect buttock size and profile WHR doesn’t reflect hips

• Actual WHR reflects both hips and buttocks

An Assumption

• If relative contributions of hips and buttocks to actual WHR didn’t vary in women cross-culturally, then frontal WHR would suffice

• Does it?• Er… probably not• Need a new stimulus set to test• Use Hadza and Americans again; attractive,

healthy, wife

Theoretical Preference

• For actual WHR

• Based on study preferences

• Weighted the profile WHR 0.7 times that of frontal WHR

• Theoretically preferred actual WHR = [(preferred frontal x1.0) + (preferred profile x 0.7)] / 1.7

Results

• Statistically analyzed men’s first choice preference of five figures for three criteria

• Hadza profile WHR selection significantly lower than Americans for all three criteria

• Prefer more protruding buttocks than Americans

Outcomes

• Americans: preferred frontal WHR = 0.7 and profile WHR = 0.65

• Hadza: preferred frontal WHR = 0.9 and profile WHR = 0.6

• Use equation for theoretically preferred actual WHRs

• Americans: 0.68• Hadza: 0.78

Actual Hadza WHR Measurements

• Mean actual WHR– Aged 17-82 = 0.83– Aged 17-24 = 0.79

• Bit higher than other populations, but not the highest

• Non-agriculturalists typically have higher female WHRs

New Figures, Fuller Analysis

• Hadza and American men’s preferences for women’s actual WHRs not as different as previous two studies suggest

• Problem with just using frontal WHR

Comparison

• Hazda women do have higher WHRs than American women

• Hadza, 17-24 years, WHR = 0.79

• American, 18-23, WHR = 0.73

• Why the difference? Some possibilities.

Parity

• WHR does rise with parity (number children born)

• Hazda TFR=6.2, average age of first child = 19

• American TFR=2.1, average of first child = 25

Diet

• Bulky, fibrous tubers significant in Hadza diet

• Require larger gut

• Humans aren’t ungulates…

Physical Activity

• Foragers more energetically active

• May favour higher androgen levels, depositing more fat in abdomen

• Raises WHR

Environmental Selection• High level foragers must be more efficient at

locomotion• Pelvis suited for locomotion not optimized for

childbirth• Evolutionary trade-off depending on environment• Less for women to forage in colder climates

– Further from the equator, the less women need to be optimized for locomotion

– Nearer equator, women contribute more resources to diet

• Possible male preferences map on to variation in females’ shape

Age-Based Selection• WHR reaches trough shortly after menarche• Male preference for WHR may be age-based

preference for nubility• Maximization of RV• Actual WHR could vary across populations with

variation in population mean postmenarcheal WHR• Hadza males’ preference of 0.78 very close to young

females’ WHR of 0.79• American males’ preference of 0.68 close to WHR of

young university aged women’s WHR (0.72-0.73)