Forensics 🔪

• Biological explanations of criminal behaviour:

  •Brain areas – frontal lobe, amygdala

  •Hormones – testosterone
• The frontal lobe of the human brain is the largest of the lobes:

  It is involved in

  • Complex cognitive processes
  • Regulating emotions
  • Attention

  
  

  Specifically the prefrontal lobe:

  • Rational decision making
  • Impulse control
• Prefrontal lobe:

  A healthy prefrontal lobe will be active when someone is

  • Controlling their impulses
  • Making informed and logical decisions
  • Paying attention
• Prefrontal lobe:

  If the frontal lobe is underdeveloped or damaged, it can result in the person having:

  • Difficulties thinking through the consequences of their actions
  • Difficulties controlling their impulses

  Therefore they might be more likely to

  • Respond with violence
  • Hurt someone when angry
  • Agree to steal something 
• Phineas Gage - 25 year old railway foreman

  Date of accident: September 13 1848

  Accident details:

  • Packing gunpowder into a hole with a steel rod
  • Spark ignited the gunpowder, sending the rod through his cheek and out the top of his head

  Before the accident: 

  • Well liked, organised, calm, and polite

  After the accident: 

  • Severe personality changes
  • Became impulsive, aggressive, and disorganised
  • Unable to continue his job as foreman

  Later life: 

  • Suffered from convulsions starting in February 1860
  • Died on May 21, 1860, near San Francisco, almost 12 years after the accident
• Phineas Gage case:

  Suggests the frontal lobe’s important role in emotions and personality, control/regulation of impulsive behaviour
• Psychopaths 😬:

  • Psychopathy and personality disorders: Linked to issues with impulse control and emotional regulation
  • Prevalence: Psychopaths make up 1% of the general population, but about 25% of prison populations
  • Brain function: Positron emission tomography (PET) and single photon emission computed tomography (SPECT) scans show dysfunction in specific brain regions of violent psychopaths
  • Prefrontal underarousal: In psychopaths, the prefrontal lobe is often underactive
  • Recidivism: Criminal psychopaths have higher recidivism rates compared to non psychopathic offenders
• PET scan of the prefrontal activity:

  A) Normal

  B) Murderer: Reduced prefrontal functioning activity

  
• PET scan:

  Positron emission tomography scan is a brain imaging technique that allows the brain to be observed when active
• Neurocriminology:

  The study of how brain structure and function influence criminal behaviour
• Adrian Raine - Pioneer in neurocriminology:

  • Studied brain differences between murderers pleading not guilty due to insanity and non murderers
  • Conducted a PET scan on 41 murderers (39 males, 2 females) and 41 non murderers
  • Findings showed that murderers had less active prefrontal lobes compared to non murderers
  • Murderers exhibited asymmetries in brain activity, with the left amygdala showing less activity than the right

  Raine's research supports neurocriminological explanations for behavior and raises ethical and societal questions about treatment and interventions
• The teenage brain:

  • The brain develops back to front, the prefrontal cortex is the last region to develop
  • The frontal lobe does not fully develop until around 25 - 30 years old
  • The limbic system develops at a faster rate than the prefrontal cortex during adolescence 

  During adolescence:

  • Increased independence from guardians 
  • Greater sense of autonomy
  • Associated with risk taking behaviour 
• The Striatum:

  • A reward centre that is hyperresponsive to feedback
  • Highly active during teenage years
  • Teens with increased activity in the striatum are more likely to participate in and enjoy risk taking behaviour 
• Limbic system - Labelled

  A) Hypothalamus: homeostasis

  B) Thalamus: relays information

  C) Amygdala: emotion

  D) Hippocampus: memory conversion

  
• The amygdala:

  • Part of the limbic system
  • One in each hemisphere
  • Activates when we feel threatened 
  • Involved in emotions, especially fear response
• Amygdala - damaged, overactive or atypical in size:

  • Triggers at a faster pace
  • Activates the fight, flight, freeze response
  • Higher rates of aggression
  • Less control of our emotions
• Amygdala - Underactive: 

  • Difficulty processing emotions
  • Lacks remorse or empathy

  People assessed as psychopaths often have underactive amygdalae
• Hormonal explanation:

  Hormones:

  • Chemical messengers secreted by glands in the endocrine system 
  • Travel through the bloodstream. 

  Testosterone:

  • Produced in male testes and female ovaries
  • Males typically produce more 
• In animals:

  • Testosterone is secreted when dominance needs to be asserted

  This can be seen when a rival is threatening to:

  • Take over an animal’s territory 
  • Deny them access to a mate
  • Endanger their offspring 
  • Prevent them from accessing food and shelter
• Social explanations of criminal behaviour:

  Social explanations can be harder to investigate because

  • They often rely upon self reporting and observational data 
  • Collected information can be prone to interpretation bias by the experimenter 
  • Criminals may not want to disclose information due to social desirability pressures 
• Social learning theory:

  • We learn behaviours by observing behaviour and the outcomes of those behaviours and imitating this 
  • Children are more susceptible to observational learning than adults, however we all learn observationally 
• 5 stages of observational learning:

  • Attention
  • Retention
  • Reproduction
  • Motivation
  • Reinforcement 
• Attention:

  The learner carefully watches how the ‘model’ completes the action/behaviour
• Retention:

  The learner makes a mental representation of what they have observed, which is stored in their memory
• Reproduction:

  The learner has the mental and physical capabilities to carry out the action/behaviour
• Motivation:

  The learner must have the desire to perform the action/behaviour
• Reinforcement:

  The learner is rewarded for the action/behaviour and is therefore more like to repeat it again in the future
• Bandura's Bobo Doll experiment 1961:

  A) 72 children

  B) 24 aggressive role model

  C) 24 non agressive role model

  D) 24 control group no model

  E) female model

  F) male model

  G) 6 boys

  H) 6 girls

  
• Bandura’s ‘Bobo Doll’ study - 1961:

  Groups:

  • 1 - observed adults acting aggressively toward a Bobo doll 
  • 2 - observed adults behaving non-aggressively around the doll
  • 3 - was not exposed to any adult models

  Procedure: 

  • After observing the adult models, children were placed in a room with the Bobo doll to see if they would imitate the behaviour

  Results:

  • Children who saw aggressive behaviour were more likely to act aggressively toward the doll
• Eyewitness memory:

  • Eyewitness testimony is used in criminal investigations 
  • Witnesses may be asked to testify in court

  This can be a problem if:

  • There was a weapon present 
  • The witness was asked a leading question 
• Weapon focus effect:

  • The tendency of people to pay attention to a weapon at the scene of a crime, at the expense of other aspects of the situation (e.g., the offender’s appearance)  

  
  

  • To increase our chance of survival we focus on the threat (the weapon)
  • Potentially problematic because information from our sensory memory must be paid attention to in order for it to be transferred to short term memory (stored)
• Weapon focus effect - possible outcomes:

  • Diverts Attention - witnesses focus on the weapon rather than other important details
  • Impairs Memory Accuracy - reduced attention to other details leads to poor memory recall of the crime scene
  • Weakens Eyewitness Testimony - less reliable eyewitness accounts make it harder to provide clear, accurate descriptions in court
  • Leads to Misidentification - reduced focus on the perpetrator increases the risk of wrongful identification
• Information processing: 

  1. Attention
  2. Encoding - information is first processed, memory is converted for storage 
  3. Storage - information is retained in memory 
  4. Retrieval - information is recovered for later use
• Reconstructive memory:

  • A theory of memory recall in which the act of retrieval is influenced by various cognitive processes, and such can be distorted by exposure to misleading information after the encoding event

  Leading questions:

  • A question that carries expectations and assumptions in the way it is constructed 
  • Exposure to these can cause the witness’ memory to be reconstructed, and thus differ from the original memory
• Loftus & Palmer (1974) - Experiment One:

  Aim: To test their hypothesis that the language used in eyewitness testimony can alter memory

  • 45 American student volunteers
  • 5 conditions
  • Participants were shown a series of videos involving traffic accidents
  • After watching, participants were asked to describe what had happened as if they were eyewitnesses, and asked specific questions, including the question “About how fast were the cars going when they (smashed / collided / bumped / hit / contacted) each other?”
• Loftus & Palmer (1974) - Experiment One:

  Findings: The estimated speed was affected by the verb used

  • Participants who were asked the “smashed” question thought the cars were going faster than those who were asked the “hit” question