Psychology 3720F/G Lecture Notes - Lecture 7: Twin, Monoamine Oxidase A, Twin Study
2 May 2018
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Theories of Aggression
1. Biological Theories
A. Ethological View
• Lorenz (1966)
• "hydraulic" model of aggression: buildup of aggressive urges will lead to aggressive
behaviour
• Applied to animal behaviour, not supported in humans
B. Evolutionary Psychology
• Genetic survival over individual survival
• Daly & Watson (2005)
• Step-parents more likely than biological parents to abuse or murder their children
o Me aggress as a eas of attaiig or aitaiig status y…
i. Establishing dominance over other males
ii. Showing jealousy when other man shows interest in mate
• Young Male Syndrme (Buss, 2004)
o More homicidal, in repro. Prime more likely to commit murder
• Status is now based on other factors: Occupational success, wealth, celebrity
C. Genetic Influences
• A persons temperament early in life usually endures
• Twin studies (Raine, 2008) Identical twins more likely to both have criminal records than
fraternal twins
• Meta-analyses estimate heritability at 40-50%
• MAOA: People with low-functioning variant of the gene at increased risk for aggressive
behaviour
• Denson et al. 2009, after being insulted Ps with low-functioning MAOA showed higher levels
of anger and hostility
• Environment has strong influence on whether tendencies manifest in behaviour
D. Hormones and Aggression
• Testosterone (T) - high levels associated with aggression (in both men and women)
• T higher among criminals convicted of violent crimes (Dabbs et al, 1995)
o Correlatio does’t eessarily iply ausatio
• VanGoozen et al. (1995)
o Tracked 50 individuals undergoing sex change
o Women receiving T became more aggressive, men receiving suppressors became less
aggressive
2. Psychological Theories
A. Freud's Dual Instinct Theory
• Eros = life instincts
o Basic survival, pleasure, reproduction
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• Thanatos = "death" instinct
o Redirects self destructive instinct toward other people
B. Frustration-Aggression Hypothesis
• Dollard (1939)
o Aggression is an automatic response to blocking of goal-directed behaviour
• Frustration always leads to aggression
• Frustration is the only cause of aggression
o Aggression increases in direct proportion to:
1. Amount of satisfaction the person anticipates before goal is blocked
• Problems: Many aggressive acts are preceded by frustration (instrumental
aggression, like Mafia hitmen)
• Frustration often results in many non-aggressive outcomes (apathy)
2. Closer person is to achieving the goal
• Displacement: Aggression deflected from source of frustration to a substitute target
• Catharsis: Idea that getting anger "out of ones system" will reduce motive to aggress
o Not supported by research! (Buschman, 2002) Opportunities for aggression usually
heighten subsequent aggression
o Makes subsequent aggression seem more appropriate
B. Revised Frustration-Aggression Hypothesis
• Berkowitz (1989)
o Any unpleasant stimulation will lead to hostile aggression
o But oly he it geerates upleasat feeligs does’t hae to e frustration, could be
also pain, heat, rejection)
C. Cognitive Neo-Associationism
• This simultaneously activates two distinct schemas, or response tendencies
• One is anger; oe shea for ager has ee atiated, it spreads… triggers eories of
previous occasions when one was angry – related negative memories, feelings & behaviors
o Leads to a fight response
• Unpleasant experiences -> Negative feelings -> Angry thoughts and associations -> fight
• Other times, the negative feelings will activate schema for fear: flight tendency
• Unpleasant experiences -> Negative feelings -> fearful thoughts and associations -> flight
• Objects/Events must prime aggression/fear
Objects: research shows the presence of guns, knives will lead to more aggressive behavior
in response to aversive arousal
• The presene of guns did not inrease aggression if the person asn’t angered to egin
ith (if they’d reeied positie feedak aout their ideas)
• Weapons Effect: The tendency for weapons to enhance aggressive thoughts, feelings and
actions
o Berhowitz & LePage (1967)
• Male Ps worked on task (generating ideas)*
o Given feedback (shocks) from confed.
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Document Summary
Theories of aggression: biological theories, ethological view. hydraulic model of aggression: buildup of aggressive urges will lead to aggressive behaviour: applied to animal behaviour, not supported in humans, evolutionary psychology, genetic survival over individual survival, daly & watson (2005) Step-parents more likely than biological parents to abuse or murder their children: me(cid:374) aggress as a (cid:373)ea(cid:374)s of attai(cid:374)i(cid:374)g or (cid:373)ai(cid:374)tai(cid:374)i(cid:374)g status (cid:271)y . Showing jealousy when other man shows interest in mate: young male syndrme (buss, 2004, more homicidal, in repro. Frustration is the only cause of aggression: aggression increases in direct proportion to, amount of satisfaction the person anticipates before goal is blocked, problems: many aggressive acts are preceded by frustration (instrumental aggression, like mafia hitmen) 1**: non-angered (1 shock) vs. angered (7 shocks: i. v. 2: object present (badminton racquets vs guns: dv***: chance to retaliate (with shocks) *ps task (cid:449)as to list ideas a pu(cid:271)li(cid:272)ity age(cid:374)t (cid:373)ight use to i(cid:373)pro(cid:448)e a (cid:373)usi(cid:272)ia(cid:374)"s pu(cid:271)li(cid:272) i(cid:373)age.
