Fear, Defense, and Aggression

Question 1

Pellis and colleagues’ in 1988

Answer 1

Different cats reacted to mice in different ways: efficient mouse killers, defensively, playing with mice. 2 conclusions:

1. Cats do not play with their prey; they are simply vacillating between attack and defense.
2. One can best understand each cat’s interactions based on a linear scale. Total aggressiveness at one end, total defensiveness at the other, and various proportions of the two in between.

Question 2

Name 2 examples of flawed research on human aggression and testosterone

Answer 2

1. Human studies are typically based on blood levels of testosterone rather than on brain levels. Blood levels of a hormone aren’t necessarily indicative of how much hormone is reaching the brain.
2. Researchers who study human aggression have often failed to appreciate the difference between social aggression, which is related to testosterone in many species, and defensive attack, which is not. Most seemingly aggressive out-bursts in humans are overreactions to real or perceived threat, and thus they are more appropriately viewed as defensive attack, not social aggression.

Question 3

Target-site concept

Answer 3

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

Question 4

Name the major conclusions of research on testosterone and aggression by Soma and colleagues

Answer 4

• Testosterone increases social aggression in males of many species; aggression is largely abolished(afschaffen) by castration in these same species.
• In some species, castration has no effect on social aggression; in still others, castration reduces social aggression during the breeding season but not at other times.
• Relation between aggression and testosterone levels is difficult to interpret because engaging in aggressive activity can itself increase testosterone levels.
• The blood level of testosterone, which is most used is not a good measure. Testosterone levels in the relevant areas of the brain are more important. Testosterone can be found in particular brain sites and not in others.

Question 5

Name the 3 criteria on which categories of aggressive and defensive behaviors are based on

Answer 5

1. their topography (form)
2. the situations that elicit them
3. their apparent function.

Question 6

Colony intruder model of aggression and defense

Answer 6

Blanchard and Blanchard: Derived rich descriptions of rat intraspecific aggressive and defensive behaviors by studying the interactions between the alpha male—the dominant male—of an established mixed-sex colony and a small male intruder.

Question 7

Fear

Answer 7

The emotional reaction to threat; it is the motivating force for defensive behaviors.

Question 8

How to overcome vague, subjective, everyday concepts in the research of fear, defense and aggression?

Answer 8

Basing search for neural mechanisms on

• thorough descriptions of relevant behaviors
• environments in which they occur,
• putative(vermoedelijke) adaptive functions of such behaviors.

Question 9

Defensive behaviors

Answer 9

Behaviors whose primary function is to protect the organism from threat or harm.

Question 10

Aggressive behaviors

Answer 10

Behaviors whose primary function is to threaten or harm.