Aggression

Question 1

What happened when Klüver & Bucy (1937) destroyed the amygdala in a dominant monkey?

Answer 1

The monkey lost its dominant status in the group, showing that the amygdala plays a key role in aggression and dominance.

Question 2

What did Boccardi et al. (2010) find in habitually violent offenders?

Answer 2

They had abnormalities in hippocampal functioning, which may affect memory and emotional regulation, leading to aggression.

Question 3

How does serotonin influence aggression?

Answer 3

Serotonin reduces aggression by inhibiting responses to emotional stimuli that could trigger aggressive behavior.

Question 4

What did Mann et al. (1990) discover about serotonin depletion and aggression?
🔹 Giving dexfenfluramine (which lowers serotonin) to 35 participants:

Answer 4

✅ Men → Showed increased aggression (based on a questionnaire).
❌ Women → No significant effect.

Question 5

What did Sapolsky (1998) find about testosterone and aggression in animals?

Answer 5

Removing testosterone in different species resulted in lower aggression, proving its role in aggressive behavior.

Question 6

At what age do men have the highest testosterone levels, and how does this relate to aggression?

Answer 6

Ages 21-35 → Peak testosterone → Increased male-on-male aggression (Daly & Wilson, 1998).

Question 7

What was found about testosterone levels in violent vs. non-violent prisoners?

Answer 7

High testosterone → Mostly violent crimes.
🔹 Low testosterone → Mostly non-violent crimes.
(Dabbs et al., 1987)

Question 8

How does testosterone respond to social situations

Answer 8

It fluctuates based on the environment (Carré & Olmstead, 2015).
🔹 Changes in testosterone increase amygdala reactivity, making aggression more likely in socially threatening situations.

Question 9

Evaluation of Neural Influences
Flashcard 9
❓ What did a longitudinal PET scan study reveal about amygdala size and aggression?

Answer 9

Smaller amygdala → Higher aggression and violent behavior in men with a history of violence.

Question 10

How does the interaction between the hippocampus and amygdala influence aggression?
🔹 Raine et al. (2004):

Answer 10

Asymmetry between the hippocampus and amygdala may impair emotional processing, leading to poor aggression control.

Question 11

How does diet affect serotonin levels and aggression in vervet monkeys?

Answer 11

High tryptophan diet → Increased serotonin → Lower aggression.
🔹 Low tryptophan diet → Decreased serotonin → Higher aggression.
(Raleigh et al., 1991)

Question 12

What did Rosado et al. (2004) find about serotonin levels in aggressive dogs?

Answer 12

Aggressive dogs had 109 fewer serotonin units compared to non-aggressive dogs.

Question 13

What is the difference between aggression and dominance?

Answer 13

Aggression = Used to inflict harm.
🔹 Dominance = Used to achieve status. (Mazur, 1985)

Question 14

How does testosterone influence behavior in women?

Answer 14

Eisenegger et al. (2011): Testosterone can make females nicer, depending on the situation. It promotes status-seeking behavior, which may or may not involve aggression.

Question 15

What did Hutchings & Mednick (1975) discover in their adoption study on aggression?
🔹 Studied 14,000 adoptions in Denmark and found:

Answer 15

Adopted boys with criminal convictions often had biological fathers with a history of criminal violence.

📊 Key Data:

Biological Parent Conviction Adoptive Parent Conviction Adoptive Parent No Conviction
✅ Yes 36.2% 21.4%
❌ No 11.5% 10.5%

Question 16

What did Coccaro et al. (1997) find about genetic influences on aggression in twins?

Answer 16

Nearly 50% of the variance in direct aggressive behavior could be attributed to genetics in twin studies.

Question 17

What did Miles & Carey (1997) find in their meta-analysis of twin & adoption studies?

Answer 17

Genetic influence accounted for up to 50% of the variance in aggression.
🔹 Genes had a stronger influence on aggression as people aged (more than environment).

Question 18

What did Rhee & Waldman (2002) conclude in their meta-analysis of 51 studies?
🔹 Aggressive antisocial behavior was largely due to genetic factors.

Answer 18

💡 Takeaway: Genes play a significant role, but other factors affect how aggression is expressed.

Question 19

What did Brunner et al. (1993) find about the MAOA gene and aggression?

Answer 19

Studied a Dutch family where many male members were extremely violent (rape, arson, assault).
🔹 They had abnormally low levels of MAOA, and a defective MAOA gene was identified.

💡 Takeaway: The MAOA gene is linked to aggressive behavior.

Question 20

What are the two variants of the MAOA gene discovered by Caspi et al. (1993)?

Answer 20

MAOA-H (High activity) → Produces more MAOA enzyme.
🔹 MAOA-L (Low activity) → Produces less MAOA enzyme → Linked to higher aggression.

Question 21

How does childhood maltreatment interact with MAOA variants in aggression?

Answer 21

MAOA-L + Childhood Maltreatment → More likely to develop antisocial behavior (ASB).
🔹 MAOA-H + Maltreatment OR MAOA-L without maltreatment → No significant aggression

Question 22

What is the “warrior gene,” and how does it affect aggression?

Answer 22

MAOA-L is more common in populations with a history of warfare (~2/3 of people).
🔹 In Western societies, only 1/3 of people carry MAOA-L.
🔹 McDermott et al. (2009) → MAOA-L carriers showed higher aggression when provoked.

Question 23

What are the problems with using convicted criminals in aggression studies?

Answer 23

Issue 1: Conviction rates are low compared to the actual number of violent attacks.
🔹 Issue 2: Convicted offenders may not be the most violent (e.g., a murderer who acted violently only once).

Question 24

How does the method of measuring aggression affect genetic influence findings?
🔹 Miles & Carey (1997) found:

Answer 24

Parental/self-reports → Showed strong genetic influence.
✅ Observational studies → Found more environmental influence.

💡 Takeaway: Different research methods may lead to different conclusions about aggression.

Question 25

What did Tiihonen et al. (2015) find about MAOA and violent behavior?

Answer 25

MAOA-L + CDH13 gene → Associated with extreme violence in Finnish prisoners. 🔹 No strong link between these genes and non-violent offenders. 💡 Takeaway: Certain gene combinations may make extreme aggression more likely.

Question 26

How might the MAOA gene explain sex differences in aggression? 🔹 Neiohoff (2014):

Answer 26

MAOA is sex-linked, carried on the X chromosome. ✅ Females have two X chromosomes, so even if they inherit MAOA-L, the other X can compensate. ✅ Males (XY) only have one X, making them more vulnerable to the effects of MAOA-L. 💡 Takeaway: The MAOA gene may explain why men are generally more aggressive than women.

Question 27

What is the ethological explanation of aggression?

Answer 27

It states that all members of the same species (conspecifics) have a set of stereotyped, innate behaviors that occur in specific conditions and do not require learning.

Question 27

What did Niko Tinbergen call these stereotyped, innate behaviors?

Answer 27

Fixed Action Patterns (FAPs) 💡 Takeaway: These are automatic, species-typical behaviors triggered by specific stimuli.

Question 28

What neural mechanism produces Fixed Action Patterns (FAPs)?

Answer 28

Innate Releasing Mechanism (IRM) 💡 Takeaway: IRMs are biological processes that activate FAPs in response to specific stimuli.

Question 29

What is ritualistic aggression?

Answer 29

threat displays → Highly ritualized behaviors meant to intimidate an opponent without actual physical violence. 💡 Takeaway: Many species avoid unnecessary fighting by using ritualistic aggression.

Question 30

What example of ritualistic aggression did Gardner & Heider (1968) find?

Answer 30

The Dani people of New Guinea engage in ritualized intergroup hostility instead of outright violence. 💡 Takeaway: Even in human societies, aggression can take a ritualistic form.

Question 31

What What did Fox (1978) observe about ritualistic aggression?

Answer 31

Males on Tory Island engage in highly ritualized "fighting" that replaces real physical combat. 💡 Takeaway: Ritualized aggression may help maintain social order without the risks of serious harm.

Question 32

How do hunting species (e.g., wolves) use instinctive inhibition in aggression?

Answer 32

Losing wolves become submissive, triggering instinctive inhibition in the dominant wolf to stop fighting. 💡 Takeaway: This prevents unnecessary killing within the species.

Question 33

Why don’t non-hunting species (e.g., doves) have the same instinctive inhibition?

Answer 33

Non-hunting species lack “weapons” (like fangs or claws), so they haven’t evolved this inhibitory mechanism. 💡 Takeaway: Humans lack natural weapons, so we may not have evolved strong inhibitions against killing each other.

Question 34

What was Lehrman’s (1953) criticism of Lorenz’s instinctive view of aggression?

Answer 34

He argued that Lorenz underestimated the role of environment in shaping aggressive behavior. 💡 Takeaway: Aggression is not purely innate—learning and experience also play a role.

Question 35

What are the key factors needed for evolution by natural selection?

Answer 35

Genetic variation Overproduction of offspring Competition Differential survival & reproduction

Question 36

What do Duntley & Buss (2004) say about human aggression?

Answer 36

The human brain evolved mechanisms for inflicting costs on others as part of survival.

Question 37

How does sexual competition relate to aggression?

Answer 37

Males evolved aggression to compete for mates, which increased reproductive success.

Question 38

What did Puts (2010) find about male competition?

Answer 38

Male traits suggest competition with other males was common among ancestors.

Question 39

What did Lassek & Gaulin (2009) find about male physicality?

Answer 39

Males have 75% more muscle mass than females.

Question 40

What did Buss (2005) find about male aggression?

Answer 40

Males are significantly more aggressive than females and more likely to die violently.

Question 41

Why do men have thicker jawbones & robust brow ridges?

Answer 41

These features likely evolved to withstand physical fights.

Question 42

Why is male sexual jealousy adaptive?

Answer 42

It evolved to prevent cuckoldry (raising another man’s child).

Question 43

What did Archer (2013) suggest about male jealousy?

Answer 43

Males are at risk of cuckoldry, so jealousy functions to deter infidelity.

Question 44

What did Buss (1988) propose about mate retention?

Answer 44

Males evolved specific mate-retention strategies to prevent infidelity.

Question 45

: What did Dobash & Dobash (1984) find about domestic violence?

Answer 45

Most battered women cite extreme jealousy as the main cause of violence.

Question 46

What did Dell (1984) find about sexual jealousy and murder?

Answer 46

17% of UK murders are due to sexual jealousy, with men being the main perpetrators and victims.

Question 47

What did Chagnon (1988) find about warriors?

Answer 47

Warriors in traditional societies have more sexual partners & children.

Question 47

Why did aggression in warfare evolve? (Livingstone Smith, 2007)

Answer 47

To gain resources, attract mates, and strengthen social bonds.

Question 48

: How does aggression increase status in combat?

Answer 48

Displays of bravery raise a warrior’s social standing, increasing survival benefits.

Question 48

How might socialisation explain gender differences in aggression?

Answer 48

Prinz (2012): Differences may be due to social learning, not evolution. Smetana (1989): Boys are punished for bad behaviour, girls are taught why it is wrong.

Question 49

Why might aggression be maladaptive?

Answer 49

It can lead to ostracism, injury, or death, reducing reproductive success.

Question 50

What did Duntley & Buss (2004) say about aggression’s costs?

Answer 50

It must have provided long-term benefits to outweigh its risks.

Question 51

What did Daly & Wilson (1988) find about murder and status?

Answer 51

In tribal societies, murderers gain social status.

Question 52

What did Campbell (1993) find about gang violence?

Answer 52

The most violent gang members often have the highest status.

Question 53

Why might women avoid physical aggression?

Answer 53

They risk losing reproductive capacity, making non-violent strategies more adaptive.

Question 53

What did Buss (2005) say about male-on-male violence?

Answer 53

It often results from status threats between males.

Question 53

What is a key criticism of evolutionary aggression theories?

Answer 53

They focus on mating success but fail to explain extreme human cruelty, which is rare in other animals.

Question 54

What did Adams (1983) find about female warriors?

Answer 54

The concept of women warriors is rare in most societies.