17.2 Fear, Defense and Aggression

Question 1

what is Fear

Answer 1

the emotional reaction to threat that motivates us to engage in defensive behaviours

Question 2

what did Barrett (2006) point out about the reasons the study of the neural basis of emotion has been so limited?

Answer 2

neuroscientists are often guided by unsubstantiated cultural assumptions about emotions
- we have words for fear, happiness, etc and so scientists often assume these emotions exist as such in the brain - so they search fro them, and this stinks

Question 3

How do biopsychologists get around the problem of folk psychology

Answer 3

base their search for neural mechanisms on the thorough descriptions of relevant behaviours, the environments in which they occur, and the putatatvie adaptive functions of the behaviours

Question 4

what is the colony intruder model of aggression and defence in rats

Answer 4

• small rat enters an established mixed sex-clony
• alpha male typically chases it away, biting its back during pursuit
• intruder eventually stops runner, turns to fight the alpha
• intruder rears on up on hind legs, facing the attacker and using forelimbs to ward off the attack
• alpha male changes to a lateral orientation, then moves sideways to try and force it off balance
• if the intruder stands firm, the alpha makes a lunge around the defenders body to try and bit its back.
• the defender will pivot in the same direction to continue its frontal orientation both e attacker to try to prevent the bite

Question 5

what were the two conclusions of the Pellis et al 1988 study on cat mouse hunting behaviours 1

Answer 5

1. cats do not play with their prey, those that appear to be playing are just switching between attack and defence
2. we can understand a cats interaction with mice by drawing a linear scale between 100% aggro and 100% defence,

Question 6

what happens to cats when treated with an anti anxiety drug

Answer 6

each cat shifted more towards full aggression from their starting position

Question 7

Are aggressive and defensive behaviours unitary sets, respectively?

Answer 7

Nope, there are several ways we distinguish between categories

Question 8

what are the three primary criteria for distinguishing categories of aggressive/defensive behaviours

Answer 8

1. topography (Form)
2. situations that elicit them
   3/ apparent function

Question 9

what is the target-site concept

Answer 9

idea that the aggressive and defensive behaviours an animal are often designed to attack specific sites on another animal while protecting specific sites on its own body

Question 10

why was the discovery that aggressive/denfisive Behaviuors are capable of being subcategorized an important first step in understanding their neural basis

Answer 10

different categories fo aggro/defnesive behaviours are mediated by different circuits, little progress was made in identifying the circuits before the categories were delineated

Question 11

what are some examples of the utility of the understanding of aggressive behaviours being categoorizable

Answer 11

1. lateral septum was once believed to inhibit all aggression bc lesions there rendered lab rats difficult to handle (called septal aggression or rage)
   - we now know that these lesions dont increase aggression, only defensiveness

Question 12

what are some examples of the fact that testosterone plays a role in social aggression in mammals, both as a function of its developmental role and sheer presence?

Answer 12

1. neonatal castration of male mice eliminates the ability fo testosterone injections to induce social aggression I nadulthood
2. adult castration eliminates social aggression in male mice that dont receive testosterone replacement injections

Question 13

is research on other (non rat) animals in terms of the aggressive in during effects of testosterone similar?

Answer 13

no, much more complex

Question 14

what are the major conclusions of the Soma et al literature review on testosterone and aggression (4)

Answer 14

1. T increases SA in the males of many species. aggro is largely abolished by castration in these species
2. some species have unaffected SA after castration, or others reduces during breeding season but not other times
3. the relation between aggro and T levels is hard to interpret bc engaging in aggro activity itself can increase T - just playing with a gun increased the T of male college students
4. blood level of T, which is commonly used, is kinda shite - T levels in relevant brain areas are wayyy more important- these studies are rare, but it has been shown that T can be synth in particular brain sites and not others

Question 15

what are the 4 pieces of evidence that demonstrate the fact that we int understand T and its role in SA in human males

Answer 15

• human males - T aggro behaviour does nt increase at puberty as T does in the blood
• not eliminated by castratin
• not increased by T injections that elevate blood T levels
• violent male criminals and aggro male athletes tend to have higher T lvl than normal, but this correlation might be reversed in terms of causality

Question 16

what are the two possible explanations for the lack of strong evidence in the involvement of testosterone in human aggression

Answer 16

1. hormonal and neural regulation of aggro in humans is different than many other mammal species
2. the research on human aggro and T is flawed

Question 17

what are the two primary reasons why it could be the case that our lack of knowledge about the role of T on human aggression is bc the research on human aggro and T is flawed?

Answer 17

1. measure T by blood levels, when that isn’t indicative of brain levels
2. researchers often fail to appreciate the difference between SA, which is related to T in many species, and defensive attack, which is nat
   - most aggressive outbursts in humans are overreaction to real or perceived threat, and they are most appropriately viewed as defensive attack, not social aggro