6.1.1 Biological Explanations

• What are biological explanations of criminal behavior based on?

  Genetic, brain, hormonal factors
• Twin studies compare concordance rates between MZ twins, who share 100% of their genes, and DZ twins, who share about 50%
• Adoption studies suggest a genetic contribution to criminal behavior if adoptees behave similarly to their biological parents.
• Match the candidate gene with its description:

  MAOA ↔️ Linked to aggressive behavior

  CDH13 ↔️ Regulates brain development
• A study by Christiansen (1977) found that MZ twins had higher concordance rates for criminal behavior than DZ
• Biological explanations of criminal behavior suggest it is solely the result of environmental factors.

  False
• Steps involved in genetic explanations of criminal behavior research

  1️⃣ Twin studies comparing MZ and DZ twins

  2️⃣ Adoption studies examining adoptee behavior

  3️⃣ Identifying candidate genes like MAOA
• Which brain regions are key to understanding criminal behavior?

  Prefrontal cortex, amygdala, hippocampus
• Reduced function in the prefrontal cortex is linked to aggression and impulsivity.
• Raine et al. (1997) found that murderers had lower activity in the prefrontal cortex
• Match the neurotransmitter with its effect on criminal behavior:

  Serotonin ↔️ Low levels increase aggression

  Dopamine ↔️ Elevated levels enhance risk-taking

  GABA ↔️ Low levels increase impulsivity
• Elevated dopamine levels have been linked to juvenile delinquency.
• What effect does low GABA activity have on behavior?

  Increased impulsivity
• What neurotransmitter regulates mood and impulsivity?

  Serotonin
• Low levels of serotonin are associated with increased aggression and impulsive behavior.
• What neurotransmitter is involved in reward and motivation?

  Dopamine
• What neurotransmitter inhibits neuronal activity and promotes calmness?

  GABA
• Low GABA levels may lead to increased irritability and impulsivity.
• Low levels of serotonin are associated with increased aggression
• Which study found that dopamine levels were higher in juvenile delinquents?

  Newcorn et al.
• Low GABA levels can indirectly contribute to criminal behavior by increasing irritability
• Biological explanations of criminal behavior are based on objective data from genetic, neuroimaging, and biochemical studies.
• What brain region did Adrian Raine's research on violent offenders focus on?

  Prefrontal cortex
• Biological explanations neglect the role of social and environmental factors
• Biological explanations alone provide a comprehensive understanding of criminal behavior.

  False
• What are the three factors proposed by biological explanations of criminal behavior?

  Genetic, brain structure, hormonal
• Order the three types of studies used in genetic explanations of criminal behavior from highest to lowest concordance rates:

  1️⃣ Twin studies (MZ twins)

  2️⃣ Twin studies (DZ twins)

  3️⃣ Adoption studies
• Which specific genes have been linked to aggression and antisocial behaviors?

  MAOA and CDH13
• The prefrontal cortex is responsible for decision-making and impulse control.
• Match the brain region with its function:

  Prefrontal Cortex ↔️ Decision-making, impulse control

  Amygdala ↔️ Processes emotions, fear, anger

  Hippocampus ↔️ Memory consolidation, spatial navigation
• Murderers have lower activity in the prefrontal cortex
• What brain region did Adrian Raine's research on violent offenders focus on?

  Prefrontal cortex
• The MAOA gene is also known as the "warrior gene" and may predispose to aggression.