Aggression: A Multivariate Approach: Biological Influences

• Hormones: Testosterone, low serotonin.

• Olweus: 15-17 year-old boys with high testosterone higher in aggression

− Linked with irritability− Anger is a prime emotion of aggression

• Females rats or monkeys injected with testosterone are more aggressive.

Aggression: A Multivariate Approach: Biological Influences

• Hormones: Testosterone, low serotonin.• Olweus: 15-17 year-old boys with high

testosterone higher in aggression− Linked with irritability− Anger is a prime emotion of aggression

• Females rats or monkeys injected with testosterone are more aggressive.

• Sensitive periods for testosterone: 5 mos. after conception and adolesence.

Conception5 months

BirthAdolescence

Late adulthood

Aggression: A Multivariate Approach: Biological Influences

• Temperament Systems• Aggression as subsystem of

Behavioral Approach (Go)• Emotionality/Affect Intensity

• Affects proneness to anger, irritability

• Negatively associated with BIS (Stop), Conscientiousness, and Affectional System (but compartmentalization possible)

Aggression: A Multivariate Approach: Environmental Influences

• Social Learning: Imitating successful aggression

• Reinforcement: Successful aggression brings rewards

• Negative Reinforcement: Aggression reinforced because it eliminates an aversive stimulus

− Gerald Patterson: Coercive family processes a major correlate of children’s aggression

Aggression: A Multivariate Approach: Environmental Influences

Innately Aversive Events

Event anger, frustration aggressive prepotency

Physical Examples: Shock, tail pinch, heat, inflicted painDavid Buss: Cheating spouses, exploitation

Natural Clue: Innate connection between a stimulus and an affective (evaluative) response: LeDoux’s Low Road: Direct connection to the amygdala

Stimulus Response+ (tender touching, sweet)

Stimulus Response — (Shock, etc.)

Innate (Natural Clue)

Aggression: A Multivariate Approach: Environmental Influences

Aversive Stimulation: Events Perceived as Aversive; LeDoux’s High Road via prefrontal cortex

Event

Cognitive appraisal in terms of interests and goals: Boss says you’re fired

Anger, frustration

Aggressive prepotency

Aggressive prepotency doesn’t necessarily lead to aggressive behavior

Aggressive prepotency doesn’t necessarily lead to aggressive behavior• Whether aggression occurs

depends temperament and partly on rational assessment of costs/benefits

• Conscious, rataional decision making can inhibit aggression.

Effortful Control and aggression: The general aggression modelAnderson and Bushman, 2002.

Prepotent, evolved cues for aggression: Berkowitz

• Aversive experiences produce tendencies for fight or flight in animals and humans.• hot temperatures• shock-induced pain• loud noises• foul odors • Crowded freeways??Berkowitz, L. (1990). On the formation and regulation of anger and aggression: a cognitive-

neoassociationistic analysis. American Psychologist, 45, 494–503.

Evolutionary Psychology and Aggression: David BussWhere’s the pfc?• Motives for aggression: Status, reputation, honor and sexual

jealousy as key motives for aggression.• Adaptive problems “to which aggression might have evolved

as a solution” (p. 608): • Co-opting resources held by others• Defending against attack• Inflicting costs on intrasexual rivals• Negotiating status and power hierarchies• Deterring rivals from future aggression• Deterring long-term mates from sexual infidelity• Reducing resources expended on unrelated children.

• Costs (e.g., possibility of retaliation) built into the module.

• Buss, D. M., & Shackelford, T. K. (1997). Human aggression in evolutionary perspective. Clinical Psychology Review, 17, 605–619.

• Duntley, J. D., & Buss, D. M. (2004). The evolution of evil. In A. G. Miller (Ed.), The Social Psychology of Good and Evil. New York: Guilford

Buss: Impulsivity as design feature of aggression as an evolved module• After being beaten, “I had stone hatred for him, and I righteously

couldn’t wait to see the look on his face when I blew him away. As soon as he popped out of the liquor store door, I charged right up to him, rammed the barrel in his chest, and pulled the trigger” (in Duntley & Buss, 2005, p. xxx).

• “Effective strategies sometimes require immediate action. Ponderous time delays and real-time extended reflection would result in failure. Stated differently, we propose that “impulsivity” is actually a design feature of certain adaptations that promotes their tactical effectiveness. The fact that they appear to external observers to be products of the lack of judicious reflection may speak to the profound inability of human intuitions to grasp the logic of evolved design, or to our moral judgments that classify certain strategies as good or bad. Speedy, immediate, real-time responses can be the product of adaptive design rather than “mechanical failure.” ” Duntley & Buss, 2004, p. 118

Explicit processing and Aggression

• Costs and benefits calculated via explicit prefrontal mechanisms.• Explicit assessments of costs/benefits influence

aggression (Tedeschi & Felson, 1994) • Aid for victim, retaliation• Likelihood of being caught (e.g., DNA

fingerprinting)• Penalties at law

• PFC is involved in active inhibition of prepotent subcortical impulsive aggression.

PFC Inhibition of sub-cortical aggression impulses: Damasio; Anderson et al.• Patients with damage to the ventromedial prefrontal cortex are

driven by immediate rather than long-term rewards• Children with damage in this area have immature, egocentric

moral reasoning and are prone to stealing and aggression. Damasio’s “somatic marker” hypothesis proposes that the deficit stems from the lack of inhibitory emotions normally attached to negative future possibilities.

• Patients with prefrontal damage originating in infancy exhibited a general lack of conscientiousness (lack of dependability, inability to plan for the future, proneness to immediate rewards rather than long term goals), impulsive rather than instrumental, goal-directed aggression, and lack of guilt for transgressions against others.

• Damasio, A. R. (1994/2000). Descartes’ error: Emotion, reason, and the human brain. New York: Quill (HarperCollins). • Anderson, S. W., Bechara, A., Damasio, H., Tranel, D., & Damasio, A. R. (1999). Impairment of social and moral

behavior related to early damage in human prefrontal cortex. Nature Neuroscience  2, 1032–1037.

PFC Inhibition of sub-cortical aggression impulses: Raine et al., 1998• Impulsive murderers had relatively lower left and right prefrontal

functioning and higher right hemisphere sub-cortical functioning. • Predatory murderers whose crimes involved planning and

deliberation had prefrontal functioning that was more equivalent to comparisons, while also having excessively high right sub-cortical activity.

• Results “support the hypothesis that emotional, unplanned impulsive murderers are less able to regulate and control aggressive impulses generated from sub-cortical structures due to deficient prefrontal regulation” (p. 319).

• Both impulsive and predatory murderers have “excessive subcortical activity” (p. 319)—what one might term “modular aggression.”

• Predatory murderers are better able to control these impulses stemming from subcortical areas because of adequate prefrontral functioning.

• Raine, A., Meloy, J. R., Buhrle, S., Stoddard, J., LaCasse, L., & Muchsbaum, M. S. (1998). Reduced prefrontal and increased subcortical brain functioning assessed using Positron Emission Tomography in predatory and affective murderers. Behavioral Sciences and the Law, 16, 319–332.