PSY344- Forensic psychology Midterm 1 lecture notes
Psy344- Lecture # 2 Jan 17
Psychological approaches to understanding crime
Today; A lot of theories why/when people offend. Nice broad background as basis for future lectures
Moral reasoning theory
>Kohlberg – 6 stage theory – you do thinks to reach the top ( first 4, last 2)
> Gibbs moral reasoning – looks at criminal behaviour (Socio-moral reasoning 4 stages)
Stages 5-6 – empathy with others is very important . Think of these stages as for everyone not just criminals.
Stages 1 & 2- Criminals (don‘t apply to children, that‘s different they haven‘t passed these stages yet)
Developmental delay ( moral not IQ) usually because of parenting style or social development.
1 of the overarching…maladaptive…social skills so they are stuck at this stage.
Powerful figures – social dominance
* Prof story; Racist buddy was saying something prejudice and rude at a wedding….- would you ever say that
to Pat? – No ofc not, he is bigger than me.
Reasoning refers to powerful authority figures. These adults haven‘t learned …. little to no perspective taking.
These are all risk factors (stressful family life growing up) but they are not a guarantee.
―Punishment can be avoided‖- the criminals will do it
Stage 1- Unilateral and Physicalistic; authority and physical consequences of behaviour ( Egocentric stage)
Stage 2- Exchanging and Instrumental; Basic social interactions> Cost Benefit- ―What am I gonna get if I
help you out?‖ ‖If I can rob the bank and get away with it I‘ll have 2 million dollars, if I get caught ill only
spend like 5 years in prison‖—Crime is justified if benefits outweigh the costs (egocentric stage)
Stage 3- Mutual & Prosocial reasoning- Psychopaths may understand this and use it in their advantage—
Crime is justified if it maintains personal relations ―all my friends do drugs so I will too‖ ( Interpersonal and
Stage 4- Systematic standards/ reasoning – Crime is justified if it is for maintains society or is sanctioned by
a social institution (reasoning understanding of complex societal systems)
Crime can be justified at any stage but most often when we are discussing criminals we are talking about stage
Hostile Attribution bias
Crick & Dodge 6step model of why some respond aggressively and others don‘t
1) Encoding of social cues
2)Interpretation of social events
3) Clarification of goals/outcomes ( dominance and revenge based rather than pro social)
4)Access or construction of response 5) choice of response
6) Performance of chosen response
Stage 6- How to respond
socially skilled will came up with more and more correct responses. You can kinda do all these steps
simultaneously . Then you can have feedback.
Circular process rather than linear, past experiences influence the new experiences.
Social moral developmental delay- criminals never learned..
Slaby and Guerra 1988-
- Kids came in already rated as hostile kids or less hostile kids
-They wanted to view the responses of these two groups ―what would you do in this situation?‖
- Responses are scored in two diff ways 1) not aggressive (affective responses) 2) aggressive but they
Pretty simple experiment they asked what would you do- then they scored it then they would ask what else
would you do, what would you do next and then score all of the responses and they looked at the affect-iveness
or aggressiveness of the first solutions vs. all the secondary solutions.
- They were looking for; 1) how hostile are the responses and 2) how many concrete responses can you actually
come up with
- The aggressive people compared to the non-aggressive people came up with significantly fewer ways of
dealing with the problem and they were much more hostile.
So the aggressive people defined the problem in hostile ways, they adopted hostile goals they didn‘t try to seek
any facts (like why are they fighting) also they found that the aggressive people didn‘t expect any consequences
of acting in an aggressive way.
-It was found that they held a set of benefits that support the use of aggression. Why would that be?
Social moral developmental delay > due to; Poor upbringing increase risk (doesn‘t have to lead to violence in
-These hostile people thought it was a legitimate response, that this was ok to do. And if they did respond that
way it would increase self-esteem and help avoid negative images. Wouldn‘t lead to suffering in the victim. So
they have this weird skewed moral reality and they don‘t think there will be any consequences for their actions.
What is that gonna do from a behavioural psychology point of view? Bad no consequence >it will reinforce it.
No consequences > so if you believe this it will reinforce the behaviour
At the fifth step- choice of respond again they are trying to cue responses so this goes back to the Slaby and
Guerra study as well.
- they think that if they are aggressive its gonna have a positive outcome. Probably cuz they have been rewarded
for it in the past. When ppl do bad things and they are out in public there is a problem with people not wanting
to be confrontational > then these people think its okey cuz no one stands up to them.
Antisocial- aggressive individuals were also more likely to hold a set of beliefs supporting their need for
Sixth step- Performance of chosen response--You actually choose what you are going to do.
- They have poor social skills- not socially awkward per se but it‘s like that guy at the cinema kicking your
chair and talking.
- So regardless of what they do (which is usually aggressive) if it is successful, it will be evaluated positively
and it will be reinforced.
- so the distinct patters across the 6 steps as compared to non-aggressive people suggests that social information processing is very influential in the development of juvenile delinquency and adult offending.
- the more steps that exhibit problems ( bad social cues, don‘t have very many choices, they rewards themselves
for choosing all the wrong choices, they say they have problems across all 6 steps well they are gonna have
greater and greater bad behaviour.
- This really highlights the need and importance of early childhood interventions of the development of such
behaviours. Its really hard if you were taught something or never punished for it as a little kid to figure it out
later as an adult. Not impossible just pretty damn hard to change a behaviour you have had for the past 15-20
years. And not very likely you are going to start doing all these behaviours you have never done before.
------back after break missed first part of the sentence----
Cognitive Behavioural Theory & Violence
Maybe it was ambiguous maybe it was neutral but they see it as hostile so they start getting angry thoughts.
When you get angry or any kind of extreme emotion, it is gonna cause physiological arousal and that‘s also
going to increase your physiological arousal as well and also psychological components as well. Basically
you‘re gonna get all worked up, really for no reason. This can happen for other people in different situations as
well not necessarily with anger but you know people who see neutral situations as negative, maybe cuz they
have low self-esteem and they get all worked up and anxious. And this arousal is going to heighten the intensity
of the angry thoughts, its circular.
But when you get more angry thoughts, cognitions it‘s most likely gonna lead up to outcomes that are more
violent and aggressive.
A range of social factors that have shown to predict violence, its pretty large we could certainly have a whole
lecture on that. Major one is family structure/ parenting style which will be our main focus for today.
Family that‘s how you learn to interact with others (siblings, parents) and then you go out from there and get
into bigger and bigger social structures ( friends and school) but it‘s at the first one at the first 4-6 years of life
where you pretty much only interact with your own family and you learn (hopefully) everything you need to in
order to go out and interact with the world. There is a clear link in the literature between severe childhood
abuse (power and control over ppl who are smaller than you when you grow up) and witnessing family violence
(where you see that that‘s okey that‘s what dad and mum do) with becoming violent.
> This association appears to be mediated through the impact on psychosocial functioning, such as problem
solving and coping abilities. Does everyone end up like this with this upbringing? No ofc not just that they have
a greater chance for it compared to ppl who don‘t have that upbringing.
Neuropsychological factors involved with violence
- This is correlational. It‘s is thought that violence may be associated with the brain but especially with damage
or malfunction to the frontal and temporal lobes
- stuff on this for psychopaths; the idea is that because they were abused their thought pathways didn‘t develop
properly so there was atrophy … or where they born like that there is.
A genetic component, because of this atrophy they have no empathy or impulse control problems.
There is a big interest in the social, environmental, genetic and neurobiological interaction of factors of violence
> Pretty clear there is something but its too new we are not sure exactly what this interaction is.
Sexual offending th
I have 5 major theories of sexual offending, the first 3 are about; why adults attack children, the 4 one is a rape
theory and the last one is an integrated model.
The first 3 we will talk about are; Finkelhor‘s four predictions, Hall & Hirshmans quadripartite model and Ward & Siegarts pathways model.rape one is Malamuths interaction model of sexual aggression and the integrated
one is by marshall *Barbaree
- Finkelhors’ Four predictions; to abusing children basically. Why do these people do it? If he can
figure out why maybe he can treat them.
1) The thinking stage ( their motivation to sexually abuse)
3 main areas where they can have one predominate over the other or all three at the same time. But if
you can figure out which one is most important to them you can address it I cognitive-behavioural
a) sexual arousal to a child; could be the sexual offending that is sexual arousal or that they are
pedophiles they are aroused by children or it could be the power and control and they can‘t do that to
people of their own size (all child molesters aren‘t necessary pedophiles)
b) Sexual offending might satisfy an emotional need; an emotional congruence with a child. Again the
need for power, anger expression things like that.
c) Blockage of sexual expression with an adult; also here they can control the child, maybe no other
source of sexual gratification available or there is no other source of sexual gratification as satisfying as
targeting children ( pedophilia, offence is the preferred form of sexual activity.
2) Giving permission ( to themselves, overcoming internal inhibitions, cuz ppl have learned from a
young age that its wrong so they must come over that)
You can acknowledge that its illegal bur on the other hand they may say its not illegal in other
countries soo its just here, they don‘t find it morally wrong, ―hey kids gotta learn about sex
anyways‖, makes more sense when you say it inside your head you try to internalize it and make it
okey ( not only with sexual offenses works with anything, saying things out load makes much more
sense). This is a continuum where there more they do it the less morally wrong it becomes.
a) Distorted beliefs about child abuse ( what is said above )
b) or they may disinhibit themselves by taking drugs and alcohol; ― I couldn‘t control myself I was
c) severe stress can trigger it as well; kind of goes back to psychosexual needs, where it just has been
building up for a long time and they just need a release.
3) Create the opportunity
a) they have to overcome external factors; like the kid and his parent‘s prob don‘t want the kid to be
sexually abused - gain trust of the child and the family, get the child alone. That‘s why people are so
upset with ex; cub‘s leader or baseball coach, it‘s someone they trusted their children with. It‘s
actually illegal to work with children without having a police check done, but people are too relaxed
about police checks, or the regulations aren‘t putting into place very well
4) Overcoming the victims resistance
a) Force; a lot of the time the perpetrator will deny they committed the offence. The victim didn‘t
resist so it must be okey. Probably forced them and Well it‘s a kid and an adult so so they don‘t
know what else to do, it is an authority figure.
b) Grooming techniques> behaviours used by the offender to overcome the resistance of the victim
over a course of time (adult rapists use this as well). Manipulate the victims to go along with sexual
conducts by gifts and threats and punishments. They start small, and when you are a kid and
someone says don‘t tell your parents about this or you might get in trouble you don‘t know you
believe that that is true. Quadrpartile Model – Hall & Hirshmann 1992
4 components necessary for offence to take place:
1) Sexual arousal by children ( just like last model)
2) Attitudes and beliefs that just child abuse ( just like last model)
3) Poor self-regulation (kinda saw this in the last model)
4) Personality problems ( this is the focus that differs from the last model) that got them to act this way.
There is situational factor, opportunity and these factors determine when this weakness caused by the
personality problem is triggered. This lead to deviant arousal, emotional disturbance and offence permitting
Pathways model- Ward & Siegart
- Talks about 4 separate but interacting psychological pathways or mechanisms that are involved in child sexual
abuse, the person who is doing it has:
1) Intimacy/Social deficits;
2) Distorted sexual scripts; they were abused as children and they don‘t know how to act in society. Don‘t know
the proper script, don‘t know how to interact with the people that you want to sexually (same for people who
were physically abused as children that become aggressive)
3) Cognitive distortions;
4) Emotional dis-regulation;
-All 4 components are involved in all sexual offences, but the treatment is based on which one pathway
dominates, which one is the focus.
- If all 4 are strong then offenders with multiple dysfunctional mechanisms can form a 5 pathway and are
hypnotised to be ―pure pedophiles‖ - most dangerous child molesters.
- Power structure> children, who have been abused, abuse others or sexually experiment.
Interaction model of sexual aggression (rape) 1993
-Switched away from child abuse to rape, this is one of the major theories.
-The two paths that interact that lead to sexual aggression
*Hostile masculinity path
*Sexual promiscuity path
(You may notice that the language im using is mostly about males attacking children. That‘s because the
majority of sexual and violent offenders are male, but small group are female. Today our focus will be on the
-Hostile masculinity path; emphasizes the role of aggressive intimate relationships and sexual conquests in the
concept of masculinity, along with valuing power, risk taking, dominance and competitiveness.
(Conquest > dominance, power.) This is what‘s in their concept of masculinity, but hopefully not in everyone‘s
concept of masculinity.
- Sexual promiscuity path; on the other hand emphasises the role of sexual behaviours in maintaining self-
esteem & peer status and the appeal of impersonal sex.
Your sexual conquests are to look cool. They are also more sexually promiscuous > this is all more likely to
lead to sexual aggression. It has to do with power, and social dominance. Has to do with Ppl high in social
dominance believe: Men better than women and so they should be able to control them and it‘s their right. Just
like with racist, it is usally culturally bound and the major ones are ; race, sex & age and sexual orientation
depending on the culture. Integrated theory- Marshal & Barbaree 1990
Theory that attempts to (although needs more research, it is very broad)
-Looks at developmental, biological, sociocultural & situational variables that lead to psychological
vulnerabilities. Which is what we should do we should look at all these factors so we can help see how we can
help them/treat them from these different angles.
Lets put it all together from the very start today:
-Negative childhood experiences ( poor parenting skills, abuse) lead to problems in forming pro-social, social,
emotional and sexual attachments.
> when we are little we learn how to interact with people, we learn right and wrong and if we don‘t we will
have a lot of problems with our social skills. On top of that of you wanna add on hormonal changes we can
- puberty which causes hormonal changes—you get much more aggressive and you start thinking about sex
more and you are all hyper. And aggression and sex could become linked, especially if you have this
maladaptive upbringing they also could be linked because the neural substrates of where these drives originate
are actually like overlapping in the brain. So if you have a proper upbringing its fine, but if you are not sure
what‘s happening and all of these neural substrates start to fire at the same time you can see how they might
start getting linked. Especially in people who feel powerless cuz they have been abused and they want power,
and they are finally at an age when they are big enough to take power back and they start thinking of sex and
power and it gets all mixed up, and that‘s how psychopaths start out.
- Poor social skills > can lead to rejection of prosocial attempts at being intimate. So it‘s not like they never
learned and they just go out and do these things right away, majority try but get rejected (not doing it quite
right, weird or socially awkward)
rejected> feel bad>> aggression (anger) and these people have a hostile attribution bias so they are gonna get
extra mad and extra angry this is going to result in anger and increased likelihood of aggressive attempts instead
of prosocial > Pro social didn‘t work so aggressive attempts start.
And if the aggressive attempt has any kind of support and you are rewarded you feel its okey. If you get away
with it, that‘s rewarding and you will do it again, you did the prosocial and it didn‘t work so why would you do
-Other factors such as stress, drugs and alcohol use added on with your anger and/or sexual frustration can
impact the ability of the person to inhibit these anti-social tendencies. Taken together all of these factors can
result in a sexual offense being committed.
- Certain factors common to all the theories we have been taking about today; mixture of distorted cognitions
that allow sexual abuse of others (―its okey cuz of this‖), poorer emotional and impulse control, problems
relating to others (socially awkward) the over- arching factor that seem to relate to all of this is developmental
adversities ( poor upbringing that lead to all sorts of things; social maladaptation to society, delinquency,
antisocial behaviour etc).
Psy344 Lecture # 3
( recording is messed up beginning is missing)
most of the ‗tells‖ people believe exists in telling if someone is lying is mostly all wrong, but we aren‘t that bad
in telling if someone is lying if it is in someone we know. Because even if we say we use those ―tells‖ we use
other factors. Today; We will go through deception today and get a better understanding of it. We are going to
go over a bunch of techniques that deal with detecting deception and some that don‘t work at all. Statement validity and polygraph testing and things like that
What is deception?
- An act intended to foster in another a belief or understanding which the deceiver considers to be false.
When we are talking deception we are not talking false information, false info doesn‘t necessarily imply
deception. If someone unintentionally misremembers and they aren‘t lying they are just telling
falsehoods…doesn‘t that mean they are lying? No because they believe it is the truth, they don‘t KNOW they
Degrees of deception
- Falsification; everything being told is contrary to the truth
- Distortion; the truth is altered to fit the liars goal ( mostly tell the truth but substitute the real hero for
-Concealment; the liar hold back the truth ( not lying just not telling all that happened)
How can we potentially catch a liar?
2) Cognitive load
3) Attempted control
4) Self-presentational perspective
And none of them are really good, it‘s totally intuitive and it makes so much sense but if you actually do some
empirical research on it, it just doesn‘t hold up. Its what we learned from when we were kids, and it works
really well when its on a family member or on a friend, but not cuz these tools are so good rather that we know
our friend so well. Using on someone u don‘t know it goes down to 50/50 chance.
Emotional Approach ( probably the worst of them all)
- Premise that lying causes emotions that differ from those experienced while telling the truth
Ex, may feel fear of being judged as not being truthful
> this may differ based on context; how severe is it, are u trying to lie your way out of a murder or from stealing
- experiencing emotion while lying can have behavioural consequences; fear of apprehension causes the
experience of stress and arousal.
and this can result in things like higher voice pitch, sweating, speech errors, overt your gaze, increased blushing
( im saying these are premises not saying if it‘s true or false, they make sense tho pretty intuitive)
- Basis of his hypothesis - The stronger these emotions are experience the liars the more likely is it that these
emotions will leak out leaving visible traces in your demeanor ( appearance/ body language)
- Problems with this??
* Even if I didn‘t murder someone I will still exhibit all of these responses because im nervous im being
accused of murdering someone, even though im telling the truth.
These things are certainly correlated with nervousness.
*Gaze – you could be shy, culture in some cultures its totally rude to look someone in the eyes that‘s an
aggressive move and means you want to fight them.
* where is the research; maybe this is a third variable confound.
…Lets say you are a practiced liar, or an innocent who will be more nervous under interrogation? Innocent
person who isn‘t used to it. Cognitive Load Approach – Vrij 2008 ( works a bit better but still a few confounds)
- Premise that lying is more cognitively demanding than telling the truth.
you are faster if you don‘t have to make something up, also its harder to remember a lie, and it also has to
appear detailed enough as something that you actually experienced and that‘s pretty difficult, also simple
enough to be remembered.
- research show that cog demanding tasks make it harder to have eye contact with someone cuz its distracting to
- fewer body movements cuz your thinking a lot
- Long pauses
Problems with this?
* All signs of nervousness as well
*some scientific validation in that when you are telling the truth you will be a lot faster at it, but also depends
maybe you just didn‘t notice something and you are trying to remember if you remember it. Also if you are very
practiced at lying you are going to be very quick. Also all of these reaction times between lying and telling the
truth they need to be measured within milliseconds of accuracy so in the real world it itsnt very applicable
*a tiny bit better than the emotional one still..
Attempted control Approach- Vrij 2004
- This is the idea that liars may be aware that internal processes could result in cues to deception.
we already kinda mentioned this what if they are practised criminals or liars, they know you are going to try
them when they lie so they try to minimize their cues but this could sometimes lead to overcompensation so you
create diff cues for deception > so instead of tapping your hand a lot you keep hand rigidly still instead.
Problems with this?
- Is it that they have body movements, few, a lot, nothing basically if you move or don‘t them you are lying.
You cant have everything.
Self-presentational perspective- DePaulo 1992;2003 ( is a bit better than the other ones, different approach.
The other one focused on how telling the truth and lying differed a qualitative difference, this approach looks at
the similarities between liars and truth tellers )
- Idea is self-regulation has been defined as regulating one‘s own behaviour to create a particular impression on
-How can focusing on the similarities help catch a liar?
Well what if the major difference between me the liar and me the truth teller is that one of them is trying to
present an honest me- self regulation. One is lying and one is telling the truth. Truth tellers actually have ground
for what they are saying.
- as a consequence liars and truth tellers are predicted to differ cognitively and behaviourally in two important
1) Deceptive statements could be embraced less by the deceiver than truthful ones – liars are aware that their
claims of honesty are illegitimately and may result in more negative feelings (they feel bad cuz they lie, or feel
bad about getting caught) this make them appear less pleasant and more tense.
Differs a bit more from what we talked about earlier still could be nervousness but at the same time being tense
and nervous is a bit different. Also cuz they are less familiar with the event ( cuz they are lying about it) they
may provide less detailed info.
2) Liars tell stories they know are untrue which may result in a deliberate attempt to seem more credible. They
are trying to control their behaviours more which actually make them seem less convincing makes them seem
tense like they are holding back just something is off about them. Problems with this?
* way to vague even if its better than the others, what is it we need to empirically test it.
* correlation with nervousness
Objective cues to deception
- results are not encouraging
- most important findings
a) reliable cues to deception is scarce
b) behaviours that actually relate to deception lack strong predictive value
out of those 4 approaches, some weren‘t related to deception at all some were but they were way to
unpredictable. Lack of strong predictive value> they are related but its more strongly correlated with something
other than deception ( like nervousness)
What did they find?
- liars seem to be somewhat more tense than truth teller; pupils dilated more, pitch of voice is higher, less
cooperative, face perceived as less pleasant ( come in rate attractiveness of these ―random ppl‖ didn‘t know it
was all about deception liars were perceived as less attractive)
- Difference in their storytelling; liars talk for shorter times, includes fewer details ( what happens if you are
shy, or concise) their stories make less sense ( this is more realistic) but if this is how you judge you prob won‘t
need a lie detector in the first place if nothing they say make sense, sound more uncertain ( less direct less
relevant details and less personal – that‘s on average im sure u met a lot of truth tellers that are like this not very
useful-) the last one I can see working; Details- liars are spontaneously correcting themselves. Admit not
remembering to a lesser extent means they say they remember with perfect clarity, liars do that a lot, truth
tellers often admit they can‘t 100 % remember. This is supposed to be an indicator of lying when actually its
probably quite the opposite. Therefor Lacking normal imperfections of truthful accounts.
How well do you think people can detect deception?
- It depends..lets make it more clear!
How good do u thin ppl are at detecting deception in strangers? – Probably pretty bad> 45-60%
How about trained experts like police or judges? – they believe they are better than the average person > not
-We suck cuz we have the wrong belief about the characteristic of deceptive behave. Lack of overlap between
the actually lying cues and the subjective (what we think is associated with lying) cues.
- majority of studies show that liars aren‘t necessarily more nervous than truth-tellers ( so the whole list is just
useless cuz they are all pretty much based on nervousness) > opposite of what we have been doing for 30 years
What about real life?
Reid Technique Manual on Lying
-Reid technique is pretty much psychological warfare that makes you confess to crime weather you did it or
- Reid manual are very over confident claims to catch liars 80% of the time—wow I wanna read the study that
backs that up! Oh there is none -.- not an empirically supported claim or you can‘t say that- it‘s just totally
intuitive. Kassin and Fong 1999 (really cool author)
- Randomly assigned participants to control group or training in catching deception with the Reid technique
--- Group who received training became more confident, and had more reasons for their judgements. ― I know
your lying I saw this example in the manual
Controls had an accuracy level of 56% BUT trainees had an accuracy level of only 46 % WORSE :o
why? Confirmation bias – they knew what they were looking for and so they only looked for that and ignored
the rest of the stud going on. Confidence doesn‘t correlate with accuracy. Instructions made them worse by
using these techniques that actually relate more to nervousness than lying.
- inefficient and counterproductive for deception detection >> problem Reid technique is one of the most widely
used techniques in this country………that‘s just bad
Lets move on to some BETTER techniques
Detected deception from verbal content
Computer based- you think it would work better because it is human control? Ppft no
3 computer based ones
1) voice stress analysis 2) Layered voice stress analysis 3) Linguistic inquiry ad word count
Voice stress analysis ( from the 80s)
- psychological stress evaluation—the premise is that by measuring the muscle responsible for producing
speech, it may be possible to infer the speaker‘s mental state > stress levels are being measured.
It‘s based on the idea of micro-tremors that can be detected by electrodes, but not by the eye
* not scientifically valid or reliable
* It basically measures stress, and not deception so stress must be strongly correlated with stress in order for it
to be predictive. And well stress is related to nervousness more than lying. Even if it did work they would have
to scientifically validate bfebfejf (doesn‘t work)
Layered Voice Stress analysis ( much newer)
- highly sophisticated technology
- analyzes digitized raw sound so it can identify errors in speech that the ear cant pick up. ( im not gonna say it
doesn‘t work its new enough i would say give me some scientific testing on it and come back to me.
Bogus pipeline- is a fake lie detector
Linguistic inquiry and word count (LIWC)
- Creates linguistic profile by categorizing words into diff classes.
It records and you get a transcript of whatever was said (getting close to statement validity stuff now) and it
looks at standard language dimensions, psychological processes and relativity. What do I mean ? …
psych process how emotional it was – how many emotional words were used. Or sensory – touched this smelled
that. Relativity – space and time.
This test doesn‘t necessarily work so great but the basis of the is scientifically reliable. Problem is that they are
using a computer cuz its faster but it sometimes takes out some of the nuance that a trained human could pick
- idea is that some words are less frequent in deceptive statements like first person pronounce ―I did this‖
- some are more frequent- negative emotional words Problem is that they focused on the pronouns and emotions when they should have focused on the
psychological processes especially the senses and the relativity of space and time.
-67% accuracy rate, not great but better than before
Statement Validity Analysis
-Back to human based one. Most widely used technique based on verbal content
-Premise; if a statement is based on an actual experience it will differ in content & quality from a statement
- This is a 4 stage procedure, it‘s the 3d one that‘s the important one where the actual deception detection comes
1) Thorough analysis of the case file—trying to figure out all the pieces of the story
2) The you start a semi-structured interview based on information gleaned from evidence ( audio tape and
3) Criteria based content analysis – but this time you have a human doing it. 19 criteria grouped into 5 diff
categories; general characteristics, specific contents, peculiarities of content, motivation-related content and
offence specific content. > they are looking for logical structures, self-deprecation, then they score it over these
original use for this wasn‘t for a suspect it was actually children for children who had accused someone for
4) Validity checklist
look what criteria are present or not. > they add it up and the more criteria present the stronger ―evidence‖ that
the story is based on a genuine truthful experience.
- overall accuracy rating of 73%
-proved equally good for detecting truthful and fabricated accounts.
Before it only found liars this one finds both!
- The process by which people distinguish memories of real events from memories of imagined events
-Premise is that real memories are products of perceptual processes whereas imagined are products of reflexive
- wasn‘t originally for deception detection was more for figuring out what memories were real memories.
- Real events from perceptual processes tend to contain more perceptual information (taste, smell, touch) and
contextual information (spatial & temporal) --
- 75% accuracy rate was found & equally good at detecting lies & truths.
- If you say I must have been tired cuz it was late at night … NOOOPE probably didn‘t happen. If you Know
you were tired it happened. Logical conclusions is not sensory remembering that is Reflective processes
> not deception detection yet, but we can turn it into.
- It could be easily used in conjunction/ replacement to CBCA (replace stage 3 with reality monitoring)
Psychophysiological detection of deception
Polygraph (lie detector is kinda inaccurate name its used as one but it isn‘t really – poly-graph multiple
measures of physical arousal and that physiological arousal is thought to measure lies --- But it still measures
nervousness , same responses as lies, and other physiological responses)
- blood pressure, pulse, respiration, galvanic skin response, respiration
- set up to a computer system . problem with the old fashioned ones, will make you even more nervous every
time you see that you are lying. Problem is that we have the assumption that we have a liar. - subject is asked to answer a series of questions.
-Premise is that deceptive answers will produce physiological responses that can be differentiated.
- rejected in court but its still allowed in criminal investigations. Gotta be able to catch truth tellers as well for it
to be totally valid. Default mode is oh they must be lying if it comes out as inconclusive.
- Useful investigation tool > leads to evidence pertaining in the right direction in order to find ―real‖ info later.
There is two main polygraph tests
- the one we see on tv all the time which I would claim isn‘t the best one
- A method of polygraph testing that compares reaction to control questions concerning past transgressions to
questions relevant to the crime under investigation – the idea is that a guilty person should react more strongly
to the relevant question.
Start with getting them comfortable to get a baseline with basic info > the questions are formulated from that
info and the info relevant to the crime. The tester must explain how it works and they are told what the
questions are to make sure they understand the question so they ant claim later that they didn‘t. and only yes
and no answers are allowed. Must understand questions enough that they can answer yes and no or it won‘t
work. They are told its 100% accurate so that the person will be less inclined to lie.
- ―Stim test‖ – subject is told to deliberately lie and the tester reports he could detect this lie.
This reinforces the validity and the client becomes anxious if they think it works really well (in reality how
much of a physiological response could u possible have if you are told to lie and you know the other person
knows it is a lie?)
run test several times to get the average of all the answers- Why? Reinforce validity of the test
Different types of questions; irrelevant questions (for baseline) and probable lie control questions stuff that most
people will lie about did u ever steal anything in your life (baseline control) and also questions relevant to the
-The test is passed if your physiological response on the probable lie questions is greater than the relevant
questions physiological response.
If they do fail you can use that against them and get them anxious so they will confess…
Control questions test is quite good at classifying guilty subjects > accuracy rate from 80-91%
-The problem is that the accuracy rates are lower for innocent subjects. There is a tendency for false positives
(finding an innocent person deceptive)
Buut this will alsso make innocent people nervous looking like a guilty person
Whats better than this??
The guilty knowledge or concealed information test ( GKT or CIT) (called both)
- used as an investigative tool, but it‘s pretty cool
-Aims to detect concealed knowledge only the guilty suspect has. Suspects are given multiple choice questions
about the crime >A guilty suspect should experience more physiological arousal to a correct choice that only a
guilty person would know.
-what weapon was used to kill mr burns? Innocent person wont react but a Guilty person will react to the
murder weapon > no need for words. You wouldn‘t have know that unless you actually did it
Problem – everyone knows mr burns was shot with a gun -.-
- Different use of the polygraph , excellent.
-accuracy * 83-96% for innocent suspects and 59-80% guilty suspects - knowledge rather than emotion – its about knowing something …
what would you guys suggest > we weed out all the innocent people using this test and then we use the other polygraph
on them cuz we have higher accuracy for catching liars.
Problems with GKT
-multiple choice cannot be biased ( right answer can’t stand out you don’t want a novelty arousal)
- innocents must not know the correct alternative ( media effects, especially in the states. In Canada its better cuz the
details of the case is kept secret until the verdict unlike us)
- Guilty suspect must know the correct answer ( maybe the perpetrator didn’t even notice some stupid details must
make sure the killer would know the answer)
Countermeasures to polygraph
> putting a tac in your shoe (step on it during the control question to fool the baseline)
>Tone out the question and just answer randomly
> Anti anxiety med
> Clench your
Psy344 Lecture #4- Jan 31
The role of the expert witness
What we are going to do today is to look at the role of expert witnesses in general and also look at it in one of
the more controversial forensic psychology topics; misidentification, child witnesses ( especially in sexual
abuse) and the problem with memory. And we will look at what an expert witness should be doing in general
and how they can screw up and become biased. The whole point is for them to be unbiased throughout the trial.
Jurors are supposed to make a decision only on two things;
1) allowable evidence and
2) any laws that the judge describes to them.
So it isn‘t everything presented in court, for example both the opening and closing statements from the
attorneys are highly biased, they are the lawyer‘s opinions and has nothing to do with fact evidence. They are
summaries of their point of view. They can suddenly put in extra things to persuade the jury. The same thing
with expert witnesses, they are supposed to unbiased educators and not pick a side, but the problem is they are
hired by one side.
In the common law system UK, US and Canada there is two types of witnesses;
1) the regular eye witness; I saw that happen
2) The expert witness; can be called in for a bunch of different reasons
What we are gonna do today is look at expert eye witnesses in general and put them in different contexts ;
misidentification, child witnesses , recovered or repressed memories and the validity of them.
We are going to see how the expert witness can help resolve these problems in court trials and actually…. I
might even make this a one or two mark question on the exam;
-What are the similarities across all cases?
-What is the expert witness supposed to do in general? (I‘ll give u a hint when we get to social framework)
We are also gonna look at what the expert has to be really really careful about when they are an expert. The
idea that when we are extremely confident of our abilities or our trait it usually means we have some kind of
over compensating or above average effect and it‘s a lot better when you think there might be a potential that you might not be the best , even if u are. EX; ppl who think that there is absolutely no chance they can ever be
prejudice; then they aren‘t exploring that possibility right? Or they don‘t even recognize when they are being
prejudice, even if it‘s unconscious or subtle. But the true no prejudice person is the person who is just a tiny bit
worried about it; not too worried about it cuz then it can actually backfire. But the ppl who are a little bit
worried are vigilant for it. ―there is a chance that I am biased against the defended especially if its some
stereotype that I learned when I was young and that I am conforming to‖ You gotta be careful and on your toes.
Im gonna talk about expert witnesses from 3 realms; UK, US and Canada (but will have my main focus on
Canada) because they are related. Both states and Canada‘s system stems from the UK, and some of the laws
are even the same. And specifically for expert witness rules on allowing them in; our (canadas) case law (the
Mohan criteria) for allowing expert witnesses in is modeled directly on the American version (the Daubert
Expert witnesses are those qualified to express a professional opinion by their training, knowledge and
experience. They provide the triers with facts (jurors) information that the jurors don‘t possess.
The role of the expert witness is to assist the court, the judge or the jury; they are not supposed to assist the
parties instructing them > whichever side hired them (lawyer). I can‘t say I think he is innocent; I can say there
is a chance he is being biased against because of his race or gender and that‘s all the expert witness can do –
can‘t say if the person is guilty or not guilty. If you put someone who is an expert, an authority figure it is
really biasing because you kind of shut off your brain and let him/her think for you.
The main difference between experts and regular witnesses are; they are allowed to give an opinion according
to the data what they think might have happened, you can see how there can be grey areas in there you have to
be really really careful, you are trying to unbias the jury by giving them education not trying to bias the jury for
or against the defendant.
Common witnesses are only allowed to make factual statements or give evidence (ofc a lot of problems with
Let‘s make it a little more clear of what they are allowed to say; an expert witness can do two things in court;
1) they can talk directly to a fact or consideration at issue – let‘s talk about bias, let‘s talk about the fallibility of
memory, let‘s talk about the demeanor of rape survivors and what ppl think from the media compared to what
they actually are. Things like that. Why would this person act this way, where does this bias come from? One
common bias is one of rape victims and child abuse victims that you see all the time is that the victim takes the
stand and they are crying, shaking and scared of the person and pointing the finger at the guy screaming ―He did
it‖ and break down etc.. .and in real life more than 75% of the time the victim has a very flat affect they have
gone through the emotional ringer of being a) attacked, sexually abused b) being cross examined by a defence
lawyer . They can feel like they can‘t connect with their partner or friend anymore so they are flat. They sit
there and respond to the question but without any emotion and blank look in their eyes. And what would that
make you think if you are in the jury and the person is supposed to be hysterical? Well they must be lying then
if they are able to stay so calm.
2) So that‘s what an expert witness does, they create as SOCIAL FRAMEWORK, and talk to you about that
and say this is actually how people react, and this person is acting in line with how people who have been
abused usually act. Although this doesn‘t mean that for sure this person raped her then—its more setting the
jury straight by getting rid of the bias/ common myths. 3 different types of standards of experts; UK, US and Canada (very similar)
Uk is much less formalized, protified than the us and Canada although there is some talk of taking on some of
the rules that Canada and the states have which is probably a good idea.
-In UK here is how you define an expert; a person who through special training, study or experience is able to
furnish the court, trial or oral hearing with scientific or technical information which is likely to be outside of a
judge, magistrate, convenor, or juror. --- Pretty much the same in Canada and states, but in CA and US they
specify what do