Detecting Deceit Flashcards
what is a lie ?
a successful or unsuccessful deliberate attempt without warning to create another belief which the communicator considers to be untrue
how good are we at lie detection ?
we underestimate our own ability to lie, but overestimate our ability to detect lies
recent research proves that teenage offenders are better at lie detection than adults or children.
how good are police at detecting lies ?
professionals are no better to non professionals, although they think they are.
professionals are better in high stake situations( murder/violence)
Methods of lie detection
Physiological responses- heart rate and sweating etc.
Non-verbal behaviour-facial expression, eye contact and body movement.
speech- what is actually said and why.
polygraph
this is a scientific measure- bodily activity such as sweating, heart rate, bp and breathing.
controlled technique- relevant and controlled questions
guilty knowledge test- altenatives given, one of the perpetrator orients to guilt
non-verbal behaviour
gaze aversion–distracting to look at a person
fewer body movements due to cognitive load
attempted control– their movements are stiff
statement validity analysis
this asses the veracity from verbal content using criteria based content analysis (CBCA)
it was originally used to determine credibility of child witnesses in sexual offence trials.
Four stages–
- analyse case file (what is known and what is disputed)
- interview to obtain a statement (record and transcribe)
- CBCA assessing quality of statement
- evaluation on validity check-list (if they are leading questions for example)
reality monitoring
difference in memory between actual and imagined experiences
memories of actual experiences contain more
- perceptual information (taste, touch, smell)
- contextual information (temporal, spatial details)
Memories of fabricated events contain more thoughts and reasoning ‘i must have been tried’
reality monitoring criteria
- Clarity
- Perceptual
- Spatial
- Temporal
- Affect
- Reconstruct ability
- Realism
- Cognitive processes
Scientific Content analysis (SCAN)
SCAN analyses the structure and content of a statement written by the interviewee about a real or fabricated event.
the presence or absence of a list of twelve criteria are said to indicate the presence of truth or lies
SCAN criteria
- denial of allegations
- social introduction
- spontaneous corrections
- lack of conviction or memory
- structure
- emotions
- objective/ subjective time
- sequence and extraneous time
- missing information
- first person singular, past tense
- pronouns
- change in language
summary
interrogation methods are still used widely, however in the uk we have moved towards more ethical interviewing.
many people falsely confess for different reasons. this can be problematic for both themselves and for society.
there re many techniques which attempt to detect deception. some can detect better than chance, but levels are well below perfection and many lack scientific credibility.
