Lecture 10: Aggression

Question 1

Agression is associated with what hormone

Answer 1

Testosterone (proximate hormonal basis)

Agre

Question 2

Aggressive behaviour affect on testosterone levels

Answer 2

increases. MORE aggression MORE testosterone –> Not the other way round

Question 3

Where does testosterone come from?

Answer 3

produced in the INTERSTITIAL CELLS of the TESTES in response to a glycoprotein produced in the brains anterior pituitary gland

Question 4

what is the role of testosterone?

Answer 4

• It is responsible for some (not thought all) secondary sexual characteristics
• it is associated with aggressive interactions
• However, it is often NOT the cause, but the CONSEQUENCE of aggression

Question 5

In humans: Individuals with higher endogenous (baseline) testosterone levels are more likely to

Answer 5

aggressive/ dominant

Question 6

in humans: when testosterone increases in anticipation of aggression this is known as

Answer 6

Priming

Question 7

In humans: if testosterone increases after aggressive incidents this is known as

Answer 7

Feedback

Question 8

The Challenge hypothesis:

Answer 8

Song sparrow: beginning of mating season increase in luteinising hormone + testosterone as bird becomes aggressive (mate guarding), not during territory as can build nest anywhere.

Question 9

Stress hormone corticosterone..

Answer 9

rises in response to individuals losing out competitive bouts. in turn makes unsuccessful individuals seek competition in future

Question 10

Testosterone has implications..

Answer 10

for fitness: individuals more likely to gain benefits associated with dominance but also costs such as stress. this is well documented in people

Question 11

is testosterone costly?

Answer 11

YES, castrates live 12 years longer! People with higher endogenous testosterone (‘type As’) die younger e.g. from coronary heart disease.

But research suggests these costs are only seen in unsuccessful ‘type As’. Having high levels of testosterone seems to carry a higher risk with a potentially greater benefit.

Question 12

adaptive significance of male-male combat

Answer 12

red deer stags fighting, competing for matings

Question 13

adaptive significance of sexual cannibalism in Praying Mantis

Answer 13

obtaining nutrients for their eggs by devouring their sexual partners

Question 14

adaptive significance of Booted Eagle Siblicide

Answer 14

larger stronger sibling often kills nest mate. although Older sibling and mother closely relating to victim, behaviour becomes adaptive for them when food is scarce. Runt is unlikely to survive & death increases chances of older sibling

Question 15

the sociobiology debate

Answer 15

1970s America,
people objected human behaviour to be genetic, now role learning & environment play is better understood. improved our understand of humans behaviour, incl. aggression, important not to use this as justification to harmful behaviour to society

Question 16

2 hormones important in control of aggression:

Answer 16

testosterone & Corticosterone (stress hormone)
-Both also released after aggressive interactions. This creates feedback loops and complicates our understanding of cause and effect

Question 17

infanticide

Answer 17

Infanticide (or infant homicide) is the intentional killing of infants. More likely to be mothers. e.g. Hanuman langur