PSYC1001 Lecture Notes - Lecture 3: Blood Pressure, Heart Rate
26 May 2018
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iii. Problems
1. Little research has examined the model, but that which has been
conducted raises serious doubts
2. Cannot account for offenders who display a mix of organized
and disorganized features
3. Statistical profiling
a. Data collected from solved crimes and analyzed using complex statistics
b. Groups of actions will tend to occur together allowing one to reveal
a typology
c. Problem: analysis is only as good as data fed into it; not always obvious
what characteristics of a crime to record
d. Analysis can be unstable if we do not have a large enough sample size
4. Geographical profiling
a. Analysis of crime scene locations in order to determine most
probably area of offender residence
b. Assumes offenders do not travel long distances from home to
commit majority of crimes
c. Can be quite accurate
e. How accurate are criminal profilers?
i. Surveys of police officers indicate profiling is useful
ii. Benefits
1. Provide greater understanding of case
2. Reinforce judgments
iii. Only 3%: profiles led to identification of offender
iv. Profiles contain ambiguous advice and can be interpreted to fit wide range of
suspects
1. Examined content of 21 profiling reports and found that 24% of
profiling opinions could be considered ambiguous
2. Ambiguous profiles interpreted to fit more than one suspect, even when
suspects quite different from one another
v. Experimental evaluations
2. Lie Detection
a. Background
i. Deception: successful/unsuccessful deliberate attempt without forewarning
to create in another a belief which communicator considers to be untrue
b. Types of polygraph tests
i. Polygraph: measure physiological change, not lies
ii. Assumption: telling a lie is more stressful than telling the truth
iii. Polygraphs measure
1. Blood pressure
2. Heart rate
3. Respiration
4. Sweating
iv. American diary study: College students told two lies/day and
community members told one lie/day
v. Uses of polygraph
1. Helps in criminal investigations
2. Verify a crime has occurred
3. Pre-employment screening for security agencies and police
vi. AU, UK, EU: polygraph is not used as part of formal legal process
vii.Polygraph used to be quite common in US, but not used for investigative
purposes
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