6b. Sexual Selection: human attractiveness & mate choice

Question 1

In order to reproduce, traits must have evolved which…

Answer 1

allow us to DISPLAY and INTERPRET the quality of potential mates

Question 2

What does attractiveness encompass?

Answer 2

The set of adaptations (physical and non-physical) that display mate quality

Question 3

What does mate choice involve?

Answer 3

The appraisal of the attractiveness of potential mates

Question 4

Women’s mate preferences

Answer 4

Low fitness variance (more concern with quality of offspring)
Quality of offspring can be achieved via (1) high investment/resources, (2) good genes
Long term - more emphasis on investment than good genes

Question 5

Women’s mate preferences (Buss, 1989)

Answer 5

Study of 37 cultures with over 10,000 participants
For long-term relationships, intelligence + kindness rated top by both men and women
Women consistently rated economic resources as important

Question 6

Why do women have a strong preference for high status males?

Answer 6

Signals resources and protection

Question 7

Why do women prefer slightly older men?

Answer 7

Status increases with age

Question 8

The importance of status

Answer 8

Women compete for men of high status
Men compete to gain status (at the expense of someone else)
Status signals resources and protection and to some extent genetic quality

Question 9

Women’s preferences for physical attractiveness

Answer 9

Athletic prowess and height (signals ability to provide and protect)
Study on personal ads - taller men got more responses
However, extreme tallness is not attractive - related to health

Question 10

Studies on facial symmetry

Answer 10

• Women prefer men with symmetrical features
• Women have relationships with men of similar levels of symmetry
• Men with lower levels of asymmetry have more sexual partners
• Facial symmetry particularly correlates with sexual success in men
• Women more likely to have affairs with men who are more symmetrical

Question 11

Why is symmetry so important?

Answer 11

Genetic predisposition to be symmetrical (bilateral symmetry)
Both sides of a bilaterally symmetrical trait (e.g. face) are coded for by the same genes
Asymmetry indicates that something has gone wrong

Question 12

Why does asymmetry occur?

Answer 12

Genetic reasons (animals with high levels of mutations have more asymmetry)
Developmental reasons (e.g. parasites, pollutants, illness)
Both disadvantageous to fitness
Random deviations are called FLUCTUATING ASYMMETRY

Question 13

Masculinity causes the formation of secondary sexual characteristics via testosterone…

Answer 13

square jaw
brow ridge
cheekbones

Question 14

Testosterone is an immunosuppressant. What does this mean?

Answer 14

Vulnerability to infections and cancers

Question 15

In order to have high levels of testosterone and stay healthy, what must a man have?

Answer 15

Good genes and development

Question 16

When do females prefer masculinised faces?

Answer 16

When most fertile (as this is when genetic signals are most important)

Question 17

Preferences for physical attractiveness are secondary to…

Answer 17

indicators of status and resources in women (particularly for long term relationships)

Question 18

Priority of investment from men due to:

Answer 18

higher bi-parental care in humans

high resource cost of human offspring

Question 19

Men’s mate preferences

Answer 19

Males are less choose - greater concern with quantity of mates
However, more parental investment than most species –> some choosiness
Choosiness also varies with extent of investment (one night stand vs. marriage)
May also vary with man’s own mate quality

Question 20

Three primary selection pressures have shaped men’s mate preferences:

Answer 20

(1) The need to mate with women capable of bearing offspring (i.e. fertile, healthy)
(2) Importance of passing on good genes to offspring
(3) Avoidance of cuckoldry

Question 21

YOUTH as an indicator of health and fertility

Answer 21

Youth is crucial because fertility declines with age
Cross culturally, men prefer women 2.5 years younger (ave.)
As men get older, they prefer increasingly younger women

Question 22

BODY SHAPE as an indicator of health and fertility

Answer 22

Research has focused on:

• Waist-to-Hip Ratio (WHR)
• Body Mass Index (BMI)

Question 23

Waist-to-Hip Ratio (WHR)

Answer 23

Female body is an hourglass shape
WHR - the diameter of the waist divided by the diameter of the hips
<1 = waist is more narrow than hips
Singh argued that WHR is more important than slimness

Question 24

What is thought to be the optimal WHR?

Answer 24

0.7

Question 25

Evidence for the role of WHR

Answer 25

WHR = 0.7 correlates with with general health and fertility
Singh argues related to optimal levels of oestrogen and resistance to certain diseases
Historically, women have used methods to alter WHR (corsets)

Question 26

Body Mass Index (BMI)

Answer 26

BMI = weight / height squared
Cue to fatness/thinness
Study with photos of real women - attractiveness ratings fell as image got fatter, and fell sharply as it got thinner
WHR was a poor predictor of attractiveness

Question 27

TRUE OR FALSE: WHR of 0.7 is optimal cross-culturally.

Answer 27

False - Hadza of Tanzania

Question 28

Urban vs. rural society preferences (WHR vs. BMI)

Answer 28

Britain vs. Malaysia
BMI was primary factor
The more industrialised the society, the lower the BMI preferred

Question 29

Other measures of sexual attractiveness (other than WHR/BMI)

Answer 29

Facial symmetry
Clear skin
Hairless body
Sexual ornaments e.g. large/symmetrical breasts, long/shiny hair

HOWEVER some of these can now be faked! E.g. shaving

Question 30

Why are men are most concerned with physical attractiveness?

Answer 30

Signals health and fertility

Question 31

Why are women most concerned with status?

Answer 31

Signals resources and protection