What is aggression?

1
What is aggression?

• Aggression Intentional behavior aimed at
  causing either physical or psychological pain.
• Key feature Intention
• Not the same as assertive or ambitious
• Examples
• Beer bottle at party
• Drunk driver

2
Why might people behave aggressively?

• Is aggression inborn?
• Instinct theorists
• Freud Aggression innate, destructive
• Freud Death instinct (Thanatos) innate impulse
  for self-destruction. Opposite of life instinct
  (Eros).
• Lorenz Aggression innate, but adaptive.
• Ethologist. Emphasized that aggressive instinct
  facilitates the individuals survival,
  reproduction.

3
Instinct theories

• Instinct theories are NOT widely accepted.
• Problems with assuming that aggression is innate

4
Problems w/Instinct Theories

• Humans vary greatly in aggressiveness.
• Cross-cultural differences (groups in South Seas
  vs. Yanomamo in South American Iroquios and
  social change)

5
Problems w/Instinct Theories

• Regional differences in aggressive behavior
• Culture of honor Homicide rates for males are
  significantly higher than those for white
  northern males, especially in rural areas. But
  this is true only for "argument-related"
  homicides.

6
Culture of honor experiments (Dov Cohen, Richard
Nisbett colleagues)

• IV A confederate accidentally bumped into the
  participant, and called the P an insulting name
  (or no incident in the control condition).
• DVs Ps guess about evaluators ratings of his
  masculinity physiological response to stress
  and behavior
• Results Southerners in insult condition were
  more likely than northerners to think they would
  be seen as less masculine, experienced increased
  cortisol and testosterone, and were slower to
  move out of the confederates way in a very
  narrow passageway.

7
Problems w/Instinct Theories

• If aggression is a human instinct, then it is
  hard to account for this variability both within
  and between cultures.

8
Problems w/Instinct Theories

• Circular reasoning
• Why do sheep herd? Because they have a herding
  instinct.
• Doesnt explain the phenomenon, just names it.

9
Biological influences on aggression

• Neural influences
• AMYGDALA -- associated with aggressive behavior
  in humans and in lower animals.
• When electrically stimulated, docile
  animals__________________ when neural activity
  in the amygdala is blocked ______________become
  __________.

10
Neural influences Interaction w/environment

• Social factors can influence the impact of these
  neural mechanisms.
• EX If a male monkey is in the presence of other,
  _______dominant monkeys, he will ____________the
  other monkeys when the _____________is
  stimulated. But if the ___________is stimulated
  while the monkey is in the presence of
  ______dominant monkeys, he will ____________but
  will ________instead.

11
Chemical/hormonal influences

• Testosterone
• Injection of testosterone will _________aggression
  in animals

12
Testosterone in humans

• Dabbs and colleagues
• Naturally occurring testosterone levels are
  higher among prisoners convicted of violent
  crimes than those convicted of nonviolent crimes.
  
• Once incarcerated, prisoners with higher
  testosterone levels violated more prison rules
• Compared fraternities within a given college
  those known to be more rambunctious, less
  socially responsible, and more crude had the
  highest average testosterone levels.
• Correlational questions about direction of
  causality and third variables

13
Genetic influences

• Twin studies
• Identical (monozygotic) twins have identical
  genetic makeup.
• Fraternal (Dizygotic) twins are no more similar
  genetically than any other siblings.
• Twin studies are based on the assumption that
  identical twins should show greater similarity on
  any trait that is presumed to be inherited than
  fraternal twins.

14
Genetic influences

• Identical twins twice as likely as fraternal
  twins to be similar in degree of criminal
  activity.
• Christiansen 7000 twins born in Denmark
• ________identical vs.______ fraternal showed
  similarity in criminal activity
• Problems
• __________identical twins ____________similar
  records
• Identical twins ___________________than do
  fraternal twins.

15
Genetic/biological vs. environment

• Debate
• Aggressive behavior results from an interaction
  between genetic/biological factors and
  environmental factors, but aggression is more
  powerfully influenced by genetic and/or
  biological factors.
• Aggressive behavior results from an interaction
  between genetic/biological factors and
  environmental factors, but aggression is more
  powerfully influenced by environmental factors.

16
Heredity vs. environment

• Example Serial killer, Joel Rifkin
• Researchers examine both environment and possible
  genetic basis (look at brain scans)
• Video clip