Aggression

Question 1

What does the ethological explanation of aggression suggest?

Answer 1

That aggression is adaptive, and doesn’t end in death of another animal but instead ends in the loser being forced into finding territory elsewhere.

Question 2

Why is it adaptive that the loser doesn’t die?

Answer 2

because if the loser died the species would risk going extinct.

Question 3

What is one reason that aggression is used in animals?

Answer 3

For dominance hierarchies, so that you get more access to resources.

Question 4

What do most aggressive encounters in animals consist of?

Answer 4

Ritualist signalling.

Question 5

What did Lorenz observe in animal aggression?

Answer 5

That most aggressive encounters consisted of ritualistic signalling, and that intra-species aggression usually never ended in death or permanent/severe damage. Aggression ends with ritual appeasement displays

Question 6

What are innate releasing mechanisms?

Answer 6

An inbuilt physiological process or structure. An environmental stimulus triggers the innate releasing mechanism which releases a specific set of behaviours. This behavioural sequence is called a fixed action pattern.

Question 7

According to Stephen Lea, fixed action patterns have 6 key features, what are they?

Answer 7

1) stereotyped or relatively unchanging sequences of behaviours.
2) Universal, because the behaviour is shown in every individual of that species.
3) Unaffected by learning, the behaviour is shown constantly regardless of experience.
4) “Ballistic” once it is set off it can not be interrupted before it is finished.
5) Single-purpose, the behaviour never occurs in response to a different stimulus.
6) Identifiable specific sign stimulus.

Question 8

What was the procedure and findings of Tinbergens research?

Answer 8

The sign stimulus, particular feature of the stimulus, that triggers the innate releasing mechanism is the sight of the red spot on its underbelly. Researchers presented a series of wooden models during their mating season.

Regardless of shape, if the fish saw a model with a red spot, they would act aggressively. It was also found that the FAPs were unchanging and when they were initiated, they always ran its course to completion.

Question 9

Evaluate the ethological explanation of aggression?

Answer 9

1) support from research. Twin and adoption studies show a great genetic component in aggression, like 50% in MZ twins, and 19% in DZ twins. Ethological approach is correct in assuming that aggression is genetic and hereditary. HOWEVER, cultural differences apply, researchers found that one kind of murder is more typical and common in white men in Southern United States than in the Northern United States. So comes from a learned social norm. Therefore, culture can override innate mechanisms, which is hard for ethological explanation to explain.
2) Limitation - aggression against the same species is not always ritualistic. Researchers observed a 4 year war where chimps of one group killed all members of another group. The violence continued even when the other expressed appeasement signals, the signals did not inhibit the aggressive behaviour of the chimps. This challenges the idea that the aggression is not harmful.
3) One limitation is that it is outdated. Researchers pointed out that FAPs may be more infleunced by environmental factors and learning experiences, for instance many FAPs are made up of several behaviours in a series. Therefore patterns of aggressive behaviours are more flexible than Lorenz thought.

Question 10

How does the amygdala impact aggression?

Answer 10

oversensitive amygdala = higher levels of aggression.

Question 11

What is the limbic system made of?

Answer 11

The hypothalamus, amygdala, and hippocampus.

Question 12

How does the orbitofrontal cortex impact aggression?

Answer 12

Serotonin has inhibitory effects on the brain, normal levels of serotonin in the Ofc are linked with reduced firing of neurons, decreased serotonin reduces this inhibition.

Question 13

What did Gospic et al study in the limbic system of aggression?

Answer 13

Some subjects were experiencing minor provocation, when reacting aggressively fMRI scans showed fast responses from the amygdala. A benzodiazepine drug reduced amygdala activity and then reduced aggression.

Question 14

What did Virkunnen et al study in the OFC of aggression?

Answer 14

Virkunnen et al compared levels of serotonin breakdown enzymes in cerebospinal fluid in impulsve violent criminals and impulsuve non-violent criminals, levels of the enzyme were lower in the impulsive violent criminals.