hormones, morphometrics & behaviour

Question 1

how are the length of your index and ring finger affected in the womb?

what does it tell us?

does the hormone levels in adults have the same effect?

any other examples of this?

Answer 1

affected by exposure to androgens e.g testosterone

higher androgen exposure ‘more masculine’ linked to lower index:ring (2D:4D) finger ratios (longer ring than index)

no correlation between ratio and sex hormone levels as adult only exposure in utero causing difference

another example is arm-to-trunk length ratio

Question 2

what is meant by pleiotrophy?

example of genetic influence in this way?

Answer 2

gene influences 2 or more seemingly unrelated phenotypic traits

e.g development of digits and genitals governed by Hox genes
regulated by sex hormones which may also affect bone growth directly

Question 3

when is the greatest difference between groups apart for 2D:4D ratio?

Answer 3

vary greatly between differet ethnic groups than genders

Question 4

what is a high 2D:4D ratio associated with?

Answer 4

high = longer index than ring and lower androgen ‘masculine hormones’ exposure

in males - lowered sperm counts
increased risk of heart disease in males, higher exam scores but reduced aggression

in females - increased risk of anorexia and pscyhopathy and lower assertiveness

Question 5

which ratio predicts ‘good traders’?

what does this indicate about exposure to androgens in utero?

Answer 5

low ratio meaning longer ring than index so high exposure to androgens in utero and ‘more masculine’

take risks and have fast reactions so prenatal androgens should increase risk preferences and rapid reflexes and scanning

Question 6

what is the difference in facial width-to-height ratio between genders?

and how to calculate it?

Answer 6

fWHR = bizygomatic width / upper facial height

higher ratio in males than females as have wider upper faces than women

due to divergence of bizygomatic width in puberty, coinciding with testosterone surge in boys

Question 7

finding regarding ice-hockey players and those dying from contact violence and face width?

Answer 7

those with wider faces commit more aggressive acts

those with narrower faces more likely to die from contact violence

Question 8

what might sensitivity to cues of fighting ability be?

how is this shown?

Answer 8

evolutionarily important

shown by fight winner more often predicted to be the winner based on looks e.g wider face which are more attractive