1. PS4029/30 Perspectives on social attributions
Lecture 5
Feb 2005

2. Lecture 5: Do attractive faces signal health?
Prototype faces (recap)
Evolutionary advantage account of attractiveness
Facial attractiveness & medical health
Facial attractiveness & genetic health
Facial attractiveness & fertility

3. 1. Prototype faces
In order to recognise faces, we must have a mental representation of “face”
This mental representation is most probably a prototype
(see neural network example L3)

4. 1. Prototype faces
Computer graphic methods are used to construct prototype images
These are synthetic images with the mean shape, color and texture information from a sample of faces
Prototype images can be thought of as visual representations of prototypes of mental representations

5. BUILDING PROTOTYPE FACES IN SHAPE AND COLOUR
warp + +

6. 2. Evolutionary advantage account of attractiveness
Evolutionary advantage view of facial attractiveness suggests that attractiveness judgements are psychological adaptations that identify good potential mates
Thornhill & Gangestad, 1999 TICS

7. 2. Evolutionary advantage account of attractiveness
Good potential mates will:
Have strong immune systems
Have healthy genetic profile
Be fertile
These people should also have attractive faces (Thornhill & Gangestad, 1999)

8. 2. Evolutionary advantage account of attractiveness
Some researchers have noted that the BIGGEST problem for the evolutionary advantage view of attractiveness is that there is no evidence that people with attractive faces are particularly healthy
Enquist et al. (2002)

9. 2. Evolutionary advantage account of attractiveness
3 methods have been used to explore this issue
Studies of:
Past incidence of health problems
Indices of genetic health (MHC heterozygosity)
Measures of fertility

10. Facial attractiveness & medical health (Kalick et al., 1998)
Individual’s health during adolescence assigned score from detailed medical records assessed by panel of doctors
B&W photographs rated for attractiveness
Male faces: No relationship between health score and attractiveness rating
Female faces: No relationship between health score and attractiveness rating

11. Facial attractiveness & genetic health (Roberts et al., 2005)
Heterozygosity at major histocompatability complex (MHC) indicates a genetic profile consistent with strong immune system
Male faces: males who had heterozygous MHC more attractive than males with homozygous MHC
Female faces: Not tested

12. VISIBLE SKIN CONDITION AND IMMUNITY TO INFECTION
heterozygous (good immunity)
homozygous (poor immunity)

13. Facial attractiveness & genetic health (Thornhill et al., 2003)
Thornhill et al. found no link between MHC heterozygosity and facial attractiveness is men
The men in their study were of diverse ages and ethnicities and this might be why
By contrast all particpants in Roberts et al’s MHC study were of the same ethnicity and a narrow age range

14. Facial attractiveness & fertility (Roberts et al. 2004)
Fertile phase of menstrual cycle is the late follicular phase
Photographs of women’s faces are more attractive when taken at this time that photograph’s of the same women’s faces taken at other times

15. Facial attractiveness & WHR (Penton-Voak et al. 2003)
A low WHR (curvy body shape) in women is an indicator of reproductive health
Women with low WHR also have attractive faces
Bodies and faces may be 2 signals of a common underlying quality (‘health’)

16. Facial attractiveness & fertility (Soler et al. 2003)
Semen quality assessed from samples using WHO guidelines
Men whose faces were judged attractive had healthier sperm than men judged relatively unattractive

17. Lecture 5: Key themes
Although little evidence that past health problems predict facial attractiveness, there is evidence that attractive faces signal reproductive and genetic health
This supports a key claim of the evolutionary advantage account of facial attractiveness

18. Next week
The relationship between facial averageness and attractiveness will be discussed
“Are attractive faces only average?”