students will explore aspects of the criminal mind n.
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Unit 8: Forensic Psychology

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Unit 8: Forensic Psychology

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  1. Students will explore aspects of the criminal mind. Unit 8: Forensic Psychology

  2. Serial killer, mass murderer, spree killer: Is there a difference? • The primary aim of criminal profiling is to reveal the behavioral make-up of an unknown offender.* • *reference:

  3. Vocabulary • Cerebrum • Cerebellum • Brainstem • Dura Mater • Pia Mater • Arachnoid mater • hemorrhage • Psychometrics • Serial killer • mass murderer • spree killer • Signature Behaviors • Signature Aspects • Psychopathology • Antecedent • PET scan • MRI • Polygraph • Subarachnoid hemorrhage • Subdural hematoma • Epidural hematoma

  4. Obj. 1: Nervous System • Major organs of the nervous system: • Brain • Cerebrum: grey & white matter, personality, front & top of brain. • •Determining Intelligence • •Determining Personality • •Thinking • •Perceiving • •Producing and Understanding Language • •Interpretation of Sensory Impulses • •Motor Function • •Planning and Organization • •Touch & Sensation

  5. Obj. 1: Nervous System Cerebellum: ‘hind brain’, motor control, coordination

  6. Obj. 1: Nervous System Lobes: The cerebrum is divided into 4 lobes, each are paired. The lobes perform specific functions.

  7. Obj. 1: Nervous System In the Brain: Brainstem: base of the brain, nerve connection pathways, sleep cycle, breathing, heart rate

  8. Obj. 1: Nervous System • Major organs of the nervous sytem: • Spinal Cord: three major functions: pathway for motor information away from brain, pathway for sensory information towards the brain, and as a center for coordinating certain reflexes

  9. Obj. 2: Membranes of the NS • Three layers of Meninges in the NS • Dura mater • Arachnoid mater • Pia mater

  10. Obj. 2 Meninges of the NS • Three types of hemorrhages can occur with reference to the meninges of the NS. • A subarachnoid hemorrhage • A subdural hematoma • An epidural hematoma

  11. Obj. 2 Meninges of the NS • An epidural hematoma similarly may arise after an accident or spontaneously. It results from a traumatic brain injury (TBI) where a build up of blood occurs between the dura mater and the skull.

  12. Obj. 2 Meninges of the NS • A subdural hematoma is a collection of blood located in a separation of the arachnoid from the dura mater. The small veins which connect the dura mater and the arachnoid are torn, usually during an accident, and blood can leak into this area.

  13. A subarachnoid hemorrhage is acute bleeding under the arachnoid; can occur spontaneously or as a result of trauma.

  14. Obj. 3 IDENTIFY AND DESCRIBE OFFENDER PROFILING METHODS • Criminal profiling is a process known by the FBI as criminal investigative analysis. • Criminal profiling consists of analyzing a crime scene and using the information to determine the identity of the perpetrator. • Profilers, or criminal investigative analysts, are highly trained and experienced law enforcement officers who study every behavioral aspect and detail of an unsolved violent crime scene

  15. Obj. 3 Background • Profiling uses the facts to develop a theory about the crime. • Traditional police work first developed a theory, then used the facts. • Contrast these two methods. Is one better than the other? Why? Is there no significant difference between the two? Why?

  16. Obj. 3 Background • Behavior • A person’s behavior is their expression of their thoughts, feelings and emotions. • Past behavior predicts future behavior

  17. Obj. 3 Background • Signature Behaviors: • Signature behaviors are those acts committed by an offender that are not necessary to complete the offense. • can be used to suggest an offender’s psychological or emotional needs (signature aspect). • best understood as a reflection of the underlying personality, lifestyle, and developmental experiences of an offender.*

  18. Obj. 3 Background • Signature Aspects: • The emotional or psychological themes or needs that an offender satisfies when they commit offense behaviors.* • Example:

  19. Obj. 3 Background:M.O. Modus Operandi • The M.O. is a learned behaviorthat is dynamic and malleable. Developed over time, the M.O. continuously evolves as offenders gain experience and confidence. Offenders refine their M.O’s as they learn from the mistakes that lead to their arrests.

  20. Obj. 3 Crime Scene Analysis • The FBI’s Crime Scene Analysis consists of six steps • 1. Profiling inputs • 2. Decision process models • 3. Crime assessment • 4. Criminal profile • 5. The investigation • 6. The apprehension

  21. 1. Profiling Inputs • This is basically a collection of all evidence, including anything found on the scene (i.e., fibers, paint chips etc.) and anything derived from the crime scene (i.e., photographs, investigator notes, measurements, etc.).

  22. 2. Decision Process Models • Evidence is arranged to locate any types of patterns, such as whether or not the crime is part of a series of crimes, what the victims have in common, etc

  23. 3. Crime Assessment • Now that the evidence has been organized, the crime scene is reconstructed. Investigators use patterns to determine what happened in what order, and what role each victim, weapon, etc. had in the crime.

  24. 4. Criminal Profile • The combined first three steps are used to create a criminal profile incorporating the motives, physical qualities, and personality of the perpetrator. Also, the investigators use this information to decide on the best way to interview the suspects based on their personality.

  25. 5. The Investigation • The profile is given to investigators on the case and to organizations that may have data leading to the identification of a suspect. The profile may be reassessed if no leads are found or if new information is learned.

  26. 6. The Apprehension • Only occurs in about 50% of cases. When a suspect is identified, he/she is interviewed, investigated, compared to the profile, etc. If the investigators have reason to believe that the suspect is the perpetrator, a warrant is obtained for the arrest of the individual, usually followed by a trial with expert witnesses including the forensic psychologist and other forensic experts, including those involved in the crime scene analysis.

  27. Obj. 4 Testing Used to Study the Criminal Mind • Psychometrics • Psychometrics deals with the scientific measurement of individual differences (personality and intelligence). • It attempts to measure the psychological qualities of individuals and use that knowledge to make predictions about behaviour

  28. Obj. 4 Testing: Psychometrics • A test can be described as an objective, systematic and standardised measure of a sample of behaviour. • A. Objectivity is where every observer of an event would produce an identical account of what took place. • B. Systematic refers to a methodical and consistent approach to understanding an event. • C. Standardised means observations of an event are made in a prescribed manner. • D. An assessment refers to the entire process of collating information about individuals and subsequently using it to make predictions.

  29. Obj. 4 Testing: Types of Tests • There are two general categories of tests, those that test for cognitive ability (i.e. intelligence quotient) and those that test for personality • Cognitive assessment tests attempt to measure an individual’s ability to process information from their environment.

  30. Test of Cognitive Ability • Cognitive tests will be given either individually or in a group setting. • Three different types of cognitive tests (collectively known as maximum performance tests): • Speed test. • Power test. • Knowledge test. • I.Q. tests typically employ all three when estimating an I.Q. score

  31. Tests of Personality Measures • A. Personality measures are more concerned with people's dispositions to behave in certain ways in certain situations.

  32. Obj. 4 Tests of Personality Measures • There are two forms of personality test: • 1. Objective personality tests—Individuals are asked to rate their own actions or feelings in set situations. • 2. Projective tests—Individuals are asked to formulate an unstructured response to some form of ambiguous stimuli e.g. Rorschach ink-blot test.

  33. Obj. 4 Problems with Psychometric Tests • 1.Social Desirability – when faced with a psychometric test many people feel they are being judged and so alter their answers accordingly. • 2. People might engage in social desirability for two reasons: • a. Self-deception – individuals are overly optimistic in their perceptions of their own positive personality features and play down their perceived negative aspects. • b. Impression management – individuals try to appear ‘nice’ because they fear social disapproval.

  34. Obj. 4 Problems with Psychometric Tests • 3. Mood seems to play a part in how people go about performing in tests, especially those concerning personality. • A. People in a good mood might answer the questionnaire completely differently than if they were in a bad mood. • B. Features of the environment (noise, heat & light) also have an impact on our moods and our cognitive abilities. • 4. If a test is not relevant to an individual’s lifestyle an individual probably will not perform well at it.

  35. Obj. 4 Problems with Psychometric Tests • 5. Possibility of bias in tests against members of ethnic subgroups of the population, e.g. newly arrived immigrants will have difficulty with an intelligence test which asks them to name past leaders of the country to which they have recently immigrated. • Most standardised psychometric tests are based on western definitions and western cultural practices. • Attempts have been made to develop culture-free tests of intelligence, but on the whole these attempts have not been successful. This is due to several factors: • Conceptions of intelligence vary widely from culture to culture. Even if the content of a test can be made culture-free, culture itself will still affect the results through directing attitudes towards tests, test-taking, competition, and so on.

  36. Obj. 5 PET Scans & MRI’s • Two types of technical instruments are used to diagnose brain abnormalities

  37. Obj. 5 PET Scans • PET Scan (Positron Emission Tomograpghy) • 1. A diagnostic imaging tool, it made it possible for physicians to receive clear data about the body’s biochemical functioning, information that was previously gathered through exploratory surgery. • Positron Emission Technology is based on molecular biology – what is happening at the cellular level. • The PET scan shows the metabolism of the targeted area.

  38. Obj. 5 PET Scans • One of the greatest benefits of PET technology is its use in treating neurological disorders such as epilepsy, Alzheimer’s disease, and other dementias. Additionally, PET scanning is able to produce images for a number of diseases that affect the brain such as post-traumatic brain injury, brain tumors, and movement disorders.

  39. Obj. 5 MRI • MRI (Magnetic Resonance Imaging) A MRI is a noninvasive medical test that helps physicians diagnose and treat medical conditions. • MRI imaging uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal structures. • MRI does not use ionizing radiation (x-rays).

  40. Obj. 5 MRI • Currently, MRI is the most sensitive imaging test of the head (particularly in the brain) in routine clinical practice. • Physicians also use the MRI examination to document brain abnormalities in patients

  41. Obj. 5 Brain Abnormalities & Abnormal Psychology • Brain Abnormalities • 1. The prefrontal cortex (PFC) of men who have antisocial personality disorder have 11% less gray matter and is less active than men with a “normal” brain. • PFC is known to inhibit the limbic system, which is an area of the brain that gives rise to emotions. • PET scans show increased activity in the thalamus, amygdale, and the limbic system by 6% compared to a “normal” brain. All of these areas control basic emotions such as aggression, sexual desire, and anger. Increased activity in these regions would suggest stronger emotion.

  42. Obj. 5 Brain Abnormalities & Abnormal Psychology • Brain Abnormalities • 2. Corpus callosum— the activity of the corpus callosum, which is the bridge that links the two sides of the brain, was 18% less active in murderers than in a “normal” brain.

  43. Obj. 5 Brain Abnormalities & Abnormal Psychology • Genetics/Environment • 1. Genetic abnormalities and parents with antisocial behavior. • 2. Birth and pregnancy complications. • 3. Drinking alcohol and heavy cigarette smoking during pregnancy. • 4. Chemical ingestion (i.e., cocaine, lead, other drugs)

  44. Obj. 5 Brain Abnormalities & Abnormal Psychology • 5. Traumatic brain injury. • 6. Electrocution. • 7. Tumors. • 8. Extreme environmental exposures (gasses, radiation). • 9. Nutritional deficiencies.

  45. Obj. 6 POLYGRAPH MACHINE • 1. Polygraph machines, commonly called "lie detectors," are instruments that monitor a person's physiological reactions. • These instruments do not, as their nickname suggests, detect lies. • They can only detect whether deceptive behavior is being displayed.

  46. Obj. 6 Polygraph Machine • 2. History of Polygraph Machines • A.1730: English writer Daniel Defoe suggests taking a person's pulse may be a way to detect whether they're telling the truth during questioning. • B.1892: English physician Sir James Mackenzie develops a pen-trace polygraph for making medical measurements of a person's heart rate. • C.1895: Italian criminologist Cesare Lombroso uses a crude polygraph to measure a suspect's blood pressure and pulse during questioning. • D.1921: Canadian-born psychologist John Larson invents the original polygraph while working in Berkeley, California. • E.1924: Used in police interrogation.

  47. Obj. 6 Polygraph Machine • How a Polygraph Test Works • 1. A polygraph is a machine that measures various different aspects of how a person's body is functioning and draws them as side-by-side lines on a moving paper chart. • 2. Each measurement is shown by a separate line (graph) and that's why the chart of multiple lines is called a polygraph: it's a many-lined graph. • 3. The measurements are of physiological (basic, body-related) things such as heartbeat, pulse, blood pressure, respiration rate, and perspiration, as well as body movement

  48. What does the data show?

  49. Obj. 6 Polygraphy • On the previous slide picture, the “NEW” data line isn’t there • The “new” equipment are two motion detecting pads. One you sit on, the other you place both your feet flat onto it. • This detects ANY type of motion, so now, unless you are a psychopath, you will not be able to deceive the polygrapher.

  50. Obj. 6 Polygraph Machine • 4.All these can be measured relatively easily; perspiration, for example, is found through what's called galvanic skin response (GSR), which is simply how much your fingertips allow small electric currents to pass over their surface (if they're moist with sweat, they conduct electricity better than normal). • 5.Why these particular measurements and not others? Because these things change quickly and detectably when a person starts lying and suddenly feels under great stress. Physiological things like this are difficult for most people to control quickly, consciously, and voluntarily