2.1 - Biological Theories

• What is the central idea of physiological explanations for criminal behavior?

  Physical differences cause crime
• Criminals, according to Lombroso, are atavistic and less developed by evolution
• Before Lombroso, most explanations for criminal behavior were religious or moralistic.
• Name three physical features identified by Lombroso as characteristic of criminals.

  Large jaw, low forehead, long arms
• Match the type of crime with its associated physical feature according to Lombroso:

  Murderers ↔️ Beak-like noses and curly hair

  Sex offenders ↔️ Thick lips and protruding ears

  Thieves ↔️ Flattened noses
• What did William Sheldon believe about personality and body types?

  They are linked
• Sheldon identified three types of body types, also known as somatypes
• According to Sheldon, mesomorphs are the most likely body type to commit crime.
• What part of the brain is linked to rationality and self-control?

  Prefrontal cortex
• Raine et al (1994) used PET scans to compare the brains of convicted killers with normal brains.
• Phineas Gage's personality changed after an iron rod damaged his brain.
• Chronological events of Phineas Gage's accident

  1️⃣ Iron rod penetrates his brain

  2️⃣ He remains conscious and talks

  3️⃣ His behavior becomes aggressive

  4️⃣ He dies 12 years later
• What disease caused impulsiveness and aggression in children during the 1920s?

  Encephalitis lethargica
• Ellis and Coontz found a correlation between peak testosterone levels in human males and the highest crime rates in early 20s
• Low levels of serotonin have been linked to higher aggression in adults and children.
• What do genetic theories of crime suggest about criminal tendencies?

  They may be inherited
• Twin studies are used to investigate the role of genes versus environment
• Christiansen's study found a higher concordance rate for criminality among identical twins compared to non-identical twins.
• In Mednick's study of adopted sons, what concordance rate was found for criminal records with biological parents?

  20%
• Jacob's syndrome involves inheriting an extra Y chromosome.
• Males with Jacob's syndrome are overrepresented in prisons and secure psychiatric hospitals.