How is a polygraph examination conducted?
- Measures physiological responses when asked series of questions by an examiner
- Small electrode placed on the finger
- Fastened tubes around torso
What is the Galvanic skin response?
Electrical responses based on sweat
Measured by how fast electricity passes through fingers
What are strengths of polygraph examinations?
- Non-invasive
- Quick results
- Affordable
- Accessible
What are weaknesses of polygraph examinations?
- Can be inaccurate
- Individuals can sometimes control their breathing
What kind of questions are asked in a polygraph examination?
- Control questions to establish individual’s natural physiological responses in conversation
- Questions relevant to purpose of examination
What is the accuracy of polygraph tests?
Accurate 80-90% of the time
What are polygraph examinations trying to measure?
Truthfulness
* Fight or flight responses
* Blood pressure
* Heart rate
* Respiration
Are polygraph results admissible in court?
No, unless the defendant confessed during a polygraph
* Examiner can testify about interviewing the defendant but cannot mention that it occurred during a polygraph
According to the research of Ekman’s classic studies, how accurate are people at detecting deception?
- Average person: accurate apprx. 58% of the time (slightly better than chance)
- Ability to detect deceit is not limited to specific situations or contexts
According to the research of Ekman’s classic studies, can anyone detect deception? If so, what is the central feature of those who can detect deception?
- Most people are not skilled at detecting deception, but some are better at it than others
- Central feature: Ability to recognize emotional and facial expressions over a short period of time
What are reasons why people are poor at detecting deception?
- Low stakes lies do not produce consistent behavioral cues associated with lying
- High stakes lies emit micro-expressions that are hard to detect
- Most people are not exposed to people who tell high stakes lies, so they never learn the cues associated with deception
- False-memories (witnesses)
What is a low stakes lie?
- “Small” lies that people attribute little consequence to
- Often thought of as justified to the person doing it
- Uncommonly planned in advance
- Low levels of stress reported when low stakes lies are told
What is a high stakes lie?
- Big lies with serious consequences
- Often lies about transgressions
What is a micro-expression?
Minor involuntary facial movements that unconsciously display a concealed emotion
* Often misinterpreted/overlooked
What role do micro-expressions play in detecting deception?
Concealed emotions can be conveyed through micro-expressions
How is a micro-expression different from a normal expression?
- Normal expressions: 0.5 - 4 seconds, easily detected, match conversation content and tone
- Micro-expressions: <0.5 seconds, occur unconsciously, hard to detect
According to lecture, why do people lie?
- Personal gain
- Personal convenience
- Avoid punishment
- Self-protection
- Self-preservational reasons
- Protection of others’ feelings
Is there any one occupation where people have been found to be good at detecting deception?
Secret Service members have been found to have good accuracy (64%)
What is the brain finger printing method for detecting deception?
- Measures stimuli and patterns in the brain
- Brain, or Murmur, waves indicate familiarity (P-30)
- Used and funded by FBI, CIA, and Navy
- Admissible in court
How does the jury honor specific values and principles we hold in American Society?
- Respects human beings by giving defendants presumption of innocence
- Values democracy by using representative groups of society to make decisions
- Considers matters of guilt or innocence as serious
- Believes convicting an innocent person is worse than letting a guilty party to go free
- Gives each defendant his/her constitutional right to a fair trial of his/her peers (6th Amendment)
What are some of the ways that we can improve the accuracy of the jury system?
- Use Juror Orientation Videotapes to educate juries
- Use professional jurors
- Teach jurors better reasoning skills
- Control the effects of pre-trial publicity on jurors
- Stop jurors from researching case material and interacting with each other before deliberation
- Have experts testify to help jurors understand their responsibilities
Can using experts help jurors make better decisions?
Yes, when subject matter is beyond jurors’ common understanding and when the testimony is scientifically valid
What did U.S. v. Ameral (1973) rule?
Expert testimony is admissible when:
* The subject matter is beyond the common understanding of the average juror
* The expert’s evidence is scientifically valid (Daubert test)
* The value of expert testimony that helps determine guilt/innocence outweighs the value of a jury being biased against a defendant
What is a Daubert test?
Determines if scientific evidence is reliable and valid
