Scottish Institute for Policing Research (SIPR) Evidence & Investigation Network Seminar, University of Aberdeen February 18, 2009 Deception Detection.

Scottish Institute for Policing Research Scottish Institute for Policing Research (SIPR)(SIPR)

Evidence & Investigation NetworkEvidence & Investigation NetworkSeminar, University of AberdeenSeminar, University of Aberdeen

February 18, 2009February 18, 2009

Deception Detection via Deception Detection via Strategic Disclosure of Strategic Disclosure of

EvidenceEvidence

Pär Anders GranhagPär Anders GranhagDepartment of Psychology Department of Psychology University of GothenburgUniversity of Gothenburg

[email protected]@psy.gu.se

Background (1)Background (1)

To be able to correctly assess To be able to correctly assess veracity is key in legal contextsveracity is key in legal contexts

There are many views on how to There are many views on how to best detect deception and truthbest detect deception and truth

Research shows that people are Research shows that people are not very good at this task (Vrij, not very good at this task (Vrij, 2008)2008)

Background (2)Background (2) A person trying to detect deception A person trying to detect deception

can face one of two situations; can face one of two situations;

(a) where there is no evidence (a) where there is no evidence speaking to the suspect’s guilt (very speaking to the suspect’s guilt (very much research)much research)

(b) where there is some evidence (b) where there is some evidence (information) speaking to the guilt of (information) speaking to the guilt of the suspect (very little research)the suspect (very little research)

Background (3)Background (3)

Traditional research on Traditional research on deception… deception…

- No background info - No background info

- No interaction between- No interaction between interviewer and suspectinterviewer and suspect

(assess short video clips)(assess short video clips)

Points of departurePoints of departure Previous research has neglected… Previous research has neglected…

……innocent and guilty suspects’ innocent and guilty suspects’ strategiesstrategies

……the information (evidence) speaking the information (evidence) speaking to the suspect’s guiltto the suspect’s guilt

… … how the use (misuse) of this how the use (misuse) of this

information can affect deception information can affect deception detection accuracydetection accuracy

General aimsGeneral aims … … a brief review of theoretical notions a brief review of theoretical notions

relevant for liars’ and truth-tellers’ relevant for liars’ and truth-tellers’ strategiesstrategies

… … review empirical research on review empirical research on suspects’ counter-interrogation suspects’ counter-interrogation strategiesstrategies

… … show that knowledge about liars’ and show that knowledge about liars’ and truth-tellers’ strategies can be used to truth-tellers’ strategies can be used to increase deception detection accuracyincrease deception detection accuracy

Theoretical part – Aim:Theoretical part – Aim:

Provide a theoretical framework Provide a theoretical framework resting upon psychological notions resting upon psychological notions from from three domainsthree domains::

1. The psychology of instrumental 1. The psychology of instrumental mind-readingmind-reading

2. The psychology of self-regulation2. The psychology of self-regulation

3. The psychology of guilt and 3. The psychology of guilt and innocenceinnocence

Mindreading: Background Mindreading: Background (1)(1)

* Edgar Allan Poe (1809-1849), father * Edgar Allan Poe (1809-1849), father of the modern detective storyof the modern detective story

* Alter ego, Detective Auguste Dupin* Alter ego, Detective Auguste Dupin

* The Purloined Letter* The Purloined Letter

* Story about a stolen letter, hidden by * Story about a stolen letter, hidden by a clever Ministera clever Minister


The Parisian Police searched the The Parisian Police searched the Minister’s house for months in order Minister’s house for months in order to find the letter,to find the letter, but without but without success. success.

They looked for secret drawers, They looked for secret drawers, probed all cushions with fine long probed all cushions with fine long needles, examined legs in the needles, examined legs in the furniture for cavities, and searched furniture for cavities, and searched the grounds around the house.the grounds around the house.


Dupin (Poe) attributes the Parisian Dupin (Poe) attributes the Parisian Police’s failure to:Police’s failure to:

” ”ill-admeasurement, or rather through ill-admeasurement, or rather through non-admeasurement, of the intellect non-admeasurement, of the intellect with which they are engaged.” with which they are engaged.”

” ”They consider only their own ideas of They consider only their own ideas of ingenuity and, in searching for ingenuity and, in searching for something hidden, advert only to the something hidden, advert only to the modes in which they would have modes in which they would have hidden the letter.”hidden the letter.”


The police failed to mindread the The police failed to mindread the Minister, whereas the Minister performed Minister, whereas the Minister performed a mind reading of the police.a mind reading of the police.

Hence, the Minister was able to predict Hence, the Minister was able to predict the actions taken by the police in order to the actions taken by the police in order to try to find the stolen letter, whereas the try to find the stolen letter, whereas the police failed to reconstruct the actions police failed to reconstruct the actions taken by the Minister in order to hide ittaken by the Minister in order to hide it


Poe draws our attention to why Poe draws our attention to why this case was so difficult to solve:this case was so difficult to solve:

(a) the police spent too much time (a) the police spent too much time thinking about their own thinking about their own strategiesstrategies

(b) their reasoning was biased by (b) their reasoning was biased by projection (false consensus) and projection (false consensus) and stereotypical thinkingstereotypical thinking

Mindreading: Definition Mindreading: Definition (I)(I)

The cornerstone of simulating the mind The cornerstone of simulating the mind of another person (‘mindreading’) is of another person (‘mindreading’) is that one imagines oneself being in the that one imagines oneself being in the other person’s situation, which will other person’s situation, which will trigger processes that are similar to trigger processes that are similar to those of the other those of the other (Malle & Hodge, 2005)(Malle & Hodge, 2005)

We practice ‘mindreading’ on a daily We practice ‘mindreading’ on a daily basis basis

““I can imagine how you must feelI can imagine how you must feel””““I guess you need a drink?I guess you need a drink?””

Mindreading: Defintion Mindreading: Defintion (II)(II)

The term ‘mindreading’ is used The term ‘mindreading’ is used in an in an instrumental mannerinstrumental manner, to , to predict future behaviour.predict future behaviour.

… …notnot in a descriptive manner, in a descriptive manner, trying to read the actual content trying to read the actual content of a person’s mind (“of a person’s mind (“The number The number you are thinking of is fouryou are thinking of is four!”). !”).

The goal of instrumental The goal of instrumental mindreading:mindreading:

To improve the ability to predict To improve the ability to predict other people’s behaviourother people’s behaviour

Traps when reading minds Traps when reading minds (I)(I)

First, there are many reasons why First, there are many reasons why interrogators may neglect the ‘mind interrogators may neglect the ‘mind of the suspect’. For example, of the suspect’. For example,

a) too occupied thinking about their a) too occupied thinking about their own tacticsown tactics

b) too eager to get a confessionb) too eager to get a confessionc) overconfident in their own ability to c) overconfident in their own ability to

detect deceptiondetect deceptiond) lack principles for strategically using d) lack principles for strategically using

the critical information at handthe critical information at hand

Traps when reading minds Traps when reading minds (II)(II)

Second, interrogators may go wrong due to Second, interrogators may go wrong due to biases like…biases like…

Projection (false consensus)Projection (false consensus) = The = The interrogator assumes that the suspect has interrogator assumes that the suspect has the same mental states as he/she would the same mental states as he/she would have had (being in the same situation), have had (being in the same situation), ““If someone would present all this If someone would present all this evidence, I would surely confessevidence, I would surely confess””

StereotypingStereotyping = The interrogator assumes that = The interrogator assumes that the suspect has mental states that the suspect has mental states that correspond to ‘the typical criminal’correspond to ‘the typical criminal’““I know this type of…- I will break him by…”I know this type of…- I will break him by…”

Mindreading: Why?Mindreading: Why?

If the interrogator is successful in If the interrogator is successful in reading the mind of the suspect, reading the mind of the suspect, then he or she can …then he or she can …

a) …more accurately predict the a) …more accurately predict the suspect’s behavioursuspect’s behaviour

b) …use these predictions to better b) …use these predictions to better plan and conduct the plan and conduct the interrogationinterrogation

Mindreading: How?Mindreading: How?

• Our mindreading ability can be Our mindreading ability can be improved if utilizing improved if utilizing

psychological theory on psychological theory on fundamental human behaviour fundamental human behaviour

and reasoningand reasoning

• The psychology of self-regulationThe psychology of self-regulation

The Psychology of Self-regulation The Psychology of Self-regulation (I)(I)

Self-regulationSelf-regulation refers to ways in which people refers to ways in which people control their behaviour (e.g., Fiske & Taylor, control their behaviour (e.g., Fiske & Taylor, 2008)2008)

Self-regulatory strategies are particularly Self-regulatory strategies are particularly primed by threatening situations primed by threatening situations

A person anticipating a threat will have a A person anticipating a threat will have a number of self-regulative methods to choose number of self-regulative methods to choose fromfrom

The common objective of these methods is to The common objective of these methods is to try to try to restore controlrestore control

The Psychology of Self-regulation The Psychology of Self-regulation (II)(II)

Decision controlDecision control; refers to the sense ; refers to the sense of control achieved when making a of control achieved when making a decision with respect to how to decision with respect to how to engage in a forthcoming aversive engage in a forthcoming aversive eventevent

Translated to crime suspects;Translated to crime suspects; decision control aims at reducing decision control aims at reducing threat by deciding on how to act threat by deciding on how to act duríng the upcoming interview duríng the upcoming interview (counter-interrogation strategies)(counter-interrogation strategies)

The Psychology of Self-regulation The Psychology of Self-regulation (III)(III)

Both guilty and innocent suspects will Both guilty and innocent suspects will view a upcoming interrogation as a view a upcoming interrogation as a threat; this threat will evoke self-threat; this threat will evoke self-regulative strategiesregulative strategies

Both guilty and innocent suspects Both guilty and innocent suspects want to change the interviewer’s want to change the interviewer’s attitude from suspicious to non-attitude from suspicious to non-suspicioussuspicious

Theoretical frameworkTheoretical framework

1. The psychology of instrumental mind-reading1. The psychology of instrumental mind-reading

2. The psychology of self-regulation2. The psychology of self-regulation

3. The psychology of guilt and 3. The psychology of guilt and innocenceinnocence

The psychology of guilt The psychology of guilt (I)(I)

Guilty suspects often hold exclusive Guilty suspects often hold exclusive knowledge about the crime; this knowledge knowledge about the crime; this knowledge can – of course - be incriminatingcan – of course - be incriminating

This self-incriminating knowledge can be This self-incriminating knowledge can be construed as a threat (an aversive stimulus)construed as a threat (an aversive stimulus)

In brief, the threat for a guilty suspect is In brief, the threat for a guilty suspect is that the interviewer may come to know that the interviewer may come to know what he knows what he knows

The psychology of guilt The psychology of guilt (II)(II)

Guilty suspects’ Guilty suspects’ decision controldecision control::

Have to decide upon what to admit, Have to decide upon what to admit, avoid and denyavoid and deny

One basic counter-interrogation One basic counter-interrogation strategy; it makes little sense to avoid strategy; it makes little sense to avoid or deny what the suspect believe the or deny what the suspect believe the interviewer to already know interviewer to already know

The psychology of guilt The psychology of guilt (III)(III)

Decision control is particularly critical Decision control is particularly critical with respect to the incriminating with respect to the incriminating information which the information which the suspect is suspect is uncertainuncertain whether or not the whether or not the interviewer holdsinterviewer holds

Basically, two strategies:Basically, two strategies:AvoidanceAvoidance (not to mention, e.g. visiting (not to mention, e.g. visiting

a certain place at a certain time)a certain place at a certain time)DenialDenial (denying, e.g. being at a certain (denying, e.g. being at a certain

place at a certain time)place at a certain time)

The psychology of The psychology of innocence (I)innocence (I)

Innocent suspects’ Innocent suspects’ decision control decision control isis coloured by…coloured by…

A belief in a just worldA belief in a just world; people will get what ; people will get what they deserve, and deserve what they get they deserve, and deserve what they get (Lerner, 1980)(Lerner, 1980)

The illusion of transparencyThe illusion of transparency; their inner ; their inner feelings/ mental states will manifest feelings/ mental states will manifest themselves on the outside (Savitsky & themselves on the outside (Savitsky & Gilovich, 2003)Gilovich, 2003)

The psychology of The psychology of innocence (II)innocence (II)

Many innocent suspects will decide to Many innocent suspects will decide to ‘tell it like it was’, and trust that ‘tell it like it was’, and trust that ‘their innocence will shine through’ ‘their innocence will shine through’ (Kassin, 2005)(Kassin, 2005)

Innocent (mock) suspects found to be Innocent (mock) suspects found to be more likely to waive their rights to more likely to waive their rights to silence, and cooperate during silence, and cooperate during investigations (Kassin, 2005)investigations (Kassin, 2005)

The psychology of The psychology of guilt and innocence (I)guilt and innocence (I)

Guilty and innocent suspects Guilty and innocent suspects have the same goal; to be have the same goal; to be perceived as innocentperceived as innocent

They may use the same major They may use the same major self-regulatory method to reach self-regulatory method to reach this goal; this goal; decision controldecision control

The psychology of The psychology of guilt and innocence (II)guilt and innocence (II)

Guilty suspects’ decision control is Guilty suspects’ decision control is assumed to be influenced by aversion, assumed to be influenced by aversion, which will result in which will result in avoidant strategiesavoidant strategies

Innocent suspects’ decision control is Innocent suspects’ decision control is assumed to be influenced by the belief assumed to be influenced by the belief in a just world and/or the illusion of in a just world and/or the illusion of transparency, which will result in transparency, which will result in much much less avoidant strategiesless avoidant strategies

Empirical part:Empirical part:

Briefly review research on Briefly review research on

guilty and innocent suspects’ guilty and innocent suspects’

counter-interrogation counter-interrogation strategiesstrategies

Guilty suspects’ Guilty suspects’ counter-interrogation strategies counter-interrogation strategies

(I)(I)

Empirical work show that…Empirical work show that…

… … a majority of guilty mock-suspects a majority of guilty mock-suspects report to have a report to have a strategystrategy when facing a when facing a police interviewpolice interview

……guilty mock-suspects tend to put their guilty mock-suspects tend to put their strategies to work during the strategies to work during the interrogation interrogation


(II)(II)… … guilty mock-suspects, if given guilty mock-suspects, if given

the opportunity, tend to the opportunity, tend to avoid avoid mentioning the critical mentioning the critical information information

… … guilty mock-suspects, if deprived guilty mock-suspects, if deprived of avoidance as a way out, tend of avoidance as a way out, tend to to denydeny that they hold that they hold incriminating knowledge.incriminating knowledge.


(III)(III)

New empirical study on how…New empirical study on how…

(a) interrogators’ degree of suspicion and (a) interrogators’ degree of suspicion and

(b) suspects’ past criminal record (b) suspects’ past criminal record

……affect guilty mock-suspects’ disclosure affect guilty mock-suspects’ disclosure of crime-relevant information of crime-relevant information (Granhag, (Granhag, Clemens & Strömwall, 2009)Clemens & Strömwall, 2009)


(IV)(IV) Participants: Participants: 45 students 45 students

45 ex-45 ex-criminalscriminals

Ex-criminals recruited via a wide-Ex-criminals recruited via a wide-spread national organization spread national organization (KRIS), helping ex-criminals (KRIS), helping ex-criminals finding their way back to a non-finding their way back to a non-criminal lifecriminal life


(V)(V) None of the students reported to None of the students reported to

have been interviewed by the have been interviewed by the policepolice

All ex-criminals had been All ex-criminals had been interviewed by the police, and all interviewed by the police, and all of them reported to have lied in of them reported to have lied in police interviewspolice interviews


(VI)(VI)Procedure:Procedure:

All mock-suspects had to imagine that All mock-suspects had to imagine that they had stolen money from a store in a they had stolen money from a store in a shopping center, and that they now shopping center, and that they now faced a police interview (only guilty faced a police interview (only guilty suspects)suspects)

Half of the ex-criminals and half of the Half of the ex-criminals and half of the students were told that they were under students were told that they were under a high degree of suspicion (vs. low)a high degree of suspicion (vs. low)


(Vii)(Vii)Procedure:Procedure:

All mock-suspects were asked All mock-suspects were asked about their counter-interrogation about their counter-interrogation strategiesstrategies

Specifically, what to disclose in Specifically, what to disclose in the ’free recall phase’ of the the ’free recall phase’ of the interrogation, and what to interrogation, and what to disclose in response to more disclose in response to more directed/specific questionsdirected/specific questions


(Vii)(Vii)

0

2

4

6

8

10

low high

Level of suspiciousness

Crim

e re

leva

nt in

form

atio

n di

sclo

sed

(free

reca

ll ph

ase)

students

ex-criminals


(8)(8) Students disclosed significantly Students disclosed significantly

more (incriminating) information more (incriminating) information than did the ex-criminalsthan did the ex-criminals

Under high (vs. low) level of Under high (vs. low) level of suspicion students disclosed suspicion students disclosed moremore information, whereas ex- information, whereas ex-criminals disclosed criminals disclosed lessless informationinformation


(8)(8) Under a high degree of suspicion naive Under a high degree of suspicion naive

(vs. experienced) mock-suspects seem to (vs. experienced) mock-suspects seem to look differently upon the ’burden of look differently upon the ’burden of proof’:proof’:

- Naive mock-suspectsNaive mock-suspects take on the burden, take on the burden, and are more willing to talk (co-operate)and are more willing to talk (co-operate)

- - Experienced mock-suspectsExperienced mock-suspects hand over the hand over the burden to the police, and are less willing burden to the police, and are less willing to talk (co-operate)to talk (co-operate)


(9)(9) What can we learn from these What can we learn from these

results?results?

1) Raise some doubt with respect 1) Raise some doubt with respect to using students as mock-to using students as mock-suspects for certain deception suspects for certain deception experimentsexperiments

2) Implications for strategic 2) Implications for strategic disclosure of evidencedisclosure of evidence

Innocent suspects’ Innocent suspects’ counter-interrogation strategies (1)counter-interrogation strategies (1)

… … significantly fewer innocent significantly fewer innocent (than guilty) mock-suspects report (than guilty) mock-suspects report to bring a strategy into the to bring a strategy into the interview room interview room

… … very few innocent mock-very few innocent mock-suspects tend to avoid mentioning suspects tend to avoid mentioning or deny holding the potentially or deny holding the potentially incriminating informationincriminating information

Innocent suspects’ Innocent suspects’ counter-interrogation strategies counter-interrogation strategies

(2)(2)

… … the principal ‘strategy’ among innocent the principal ‘strategy’ among innocent suspects seems to be to ‘to keep the suspects seems to be to ‘to keep the story real’ and ‘to tell the truth like it story real’ and ‘to tell the truth like it happened’ happened’ (Hartwig et al, 2007).(Hartwig et al, 2007).

… … innocent (vs. guilty) suspects are more innocent (vs. guilty) suspects are more prone to waive their constitutional rights prone to waive their constitutional rights to silence and agree to be interrogated. to silence and agree to be interrogated. Based on that they have nothing to hide, Based on that they have nothing to hide, and that they believe that the truth will and that they believe that the truth will come out come out (Kassin & Norwick, 2004)(Kassin & Norwick, 2004)

Suspects’ counter-interrogation Suspects’ counter-interrogation strategies: Summing upstrategies: Summing up

Suspects’ counter-interrogation Suspects’ counter-interrogation strategies are moderated by a number strategies are moderated by a number of of different factorsdifferent factors, such as…, such as…

- Mind-set (guilty vs. innocent)Mind-set (guilty vs. innocent)- Background (criminal vs. non-criminal)Background (criminal vs. non-criminal)- Level of suspicion (high vs. low) Level of suspicion (high vs. low) - Interview technique (confrontational vs. Interview technique (confrontational vs.

strategic)strategic)- Type of crime (deny act vs. deny intent)Type of crime (deny act vs. deny intent)

From empirical work to interview From empirical work to interview tactics (I)tactics (I)

The combined empirical evidence The combined empirical evidence support the basic assumptions support the basic assumptions that.. that..

(a)(a) a suspect’s a suspect’s strategystrategy is a is a reflection of his or her reflection of his or her mental mental statestate

(b) a suspect’s (b) a suspect’s behaviourbehaviour is a is a reflection of his or her reflection of his or her strategystrategy

From empirical work to interview From empirical work to interview tactics (II)tactics (II)

We know that many guilty suspects We know that many guilty suspects avoid and/or deny holding potentially avoid and/or deny holding potentially incriminating information; and that incriminating information; and that innocent suspects tend to believe innocent suspects tend to believe that the ‘truth will shine through’.that the ‘truth will shine through’.

But how do these findings translate But how do these findings translate

into an interview technique (tactic)?into an interview technique (tactic)?

Investigators’ interrogation Investigators’ interrogation strategies (1)strategies (1)

What do we know about how What do we know about how professional investigators professional investigators disclose the evidence (critical disclose the evidence (critical information) when interrogating information) when interrogating suspects?suspects?


Sources of informationSources of information::

- Recommendations from - Recommendations from interview/interrogation manualsinterview/interrogation manuals

- Studies using real-life material- Studies using real-life material

- Experimental research- Experimental research


Interrogation manualsInterrogation manuals

are either silent on how to use are either silent on how to use the available evidence the available evidence (e.g. (e.g. Gordon & Fleisher, 2002),Gordon & Fleisher, 2002), or or

recommend that the recommend that the interrogation is started by interrogation is started by confronting the suspect with the confronting the suspect with the evidence evidence (e.g. Inbau et al., 2001; (e.g. Inbau et al., 2001; Yeschke, 1997)Yeschke, 1997)


Analyses of Analyses of real-life interrogationsreal-life interrogations::

- Disclosure of evidence (together with - Disclosure of evidence (together with a suggestion of guilt) was the typical a suggestion of guilt) was the typical way to start the interrogation, occured way to start the interrogation, occured in more than 80% of the cases in more than 80% of the cases (Leo, (Leo, 1996)1996)

- British study found that on a minority - British study found that on a minority (12%) of the cases the evidence was (12%) of the cases the evidence was disclosed at the beginning of the disclosed at the beginning of the interrogation interrogation (Moston & Engelberg, 1993)(Moston & Engelberg, 1993)


Quasi-experimental research…Quasi-experimental research…

shows that experienced Swedish shows that experienced Swedish police officers do not seem to police officers do not seem to handle the available evidence handle the available evidence very strategically when very strategically when conducting an interrogation conducting an interrogation based on a brief case-file based on a brief case-file (Hartwig (Hartwig and colleagues, 2004)and colleagues, 2004)


New study on Swedish customs New study on Swedish customs officers officers (Granhag et al, 2009)(Granhag et al, 2009)

80 customs officers; 80 customs officers; - 40 investigative unit- 40 investigative unit

- 40 crime fighting unit (on the - 40 crime fighting unit (on the field)field)

Experienced professionals:Experienced professionals:Invest; M = 20, Crime fight; M = 25Invest; M = 20, Crime fight; M = 25


All participants worked through All participants worked through a detailed case file, and planned a detailed case file, and planned an interrogation with a suspectan interrogation with a suspect

Asked about their planning and Asked about their planning and how they intended to use the how they intended to use the pieces evidence that they had pieces evidence that they had identified as the most importantidentified as the most important


Customs-study; Preliminary resultsCustoms-study; Preliminary results

Investigators (n=40): Investigators (n=40):

identified 205 pieces of critical information;identified 205 pieces of critical information; 69 pieces (34%) immediately disclosed to the 69 pieces (34%) immediately disclosed to the

suspect suspect

46 pieces (22%) used in a ’strategic’ manner46 pieces (22%) used in a ’strategic’ manner


Customs-study; Preliminary resultsCustoms-study; Preliminary results

Crime fighting unit (n=40): Crime fighting unit (n=40):

identified 182 pieces of critical information;identified 182 pieces of critical information; 96 pieces (53%) immediately disclosed to the 96 pieces (53%) immediately disclosed to the

suspect suspect

11 pieces (6%) used in a ’strategic’ manner11 pieces (6%) used in a ’strategic’ manner

From empirical work to interview From empirical work to interview tactics (III)tactics (III)

We have outlined and tested the We have outlined and tested the so-called so-called The Strategic Use of The Strategic Use of EvidenceEvidence technique (the SUE- technique (the SUE-technique) technique)

The SUE-technique is very much The SUE-technique is very much a project under developmenta project under development

The SUE-technique: Some basic The SUE-technique: Some basic steps (I)steps (I)

1. Planning of the interview 1. Planning of the interview Carefully work through the case file and identify Carefully work through the case file and identify pieces of potentially incriminating information; pieces of potentially incriminating information; especially information that the suspect will not know especially information that the suspect will not know for certain that the investigator holds. Identify a) for certain that the investigator holds. Identify a) alternative explanations to this information and b) alternative explanations to this information and b) questions addressing this critical information. questions addressing this critical information.

2. Informing the suspect2. Informing the suspectIn accordance with the relevant Codes of Practice; In accordance with the relevant Codes of Practice; important that the investigator does not disclose any important that the investigator does not disclose any of the potentially incriminating information to the of the potentially incriminating information to the suspect. suspect.

3. The free recall phase3. The free recall phase The investigator should encourage the suspect to The investigator should encourage the suspect to

‘tell his or her story’‘tell his or her story’

The SUE-technique: Some basic The SUE-technique: Some basic steps (II)steps (II)

4. Questions pertaining to alternative explanations4. Questions pertaining to alternative explanationsAsk questions aimed at ruling out alternative Ask questions aimed at ruling out alternative explanations to the evidenceexplanations to the evidence

5. Questions ‘addressing’ the evidence 5. Questions ‘addressing’ the evidence Questions addressing the potentially incriminating Questions addressing the potentially incriminating information; these questions should not reveal what information; these questions should not reveal what the investigator knows.the investigator knows.

6. Securing the suspect’s statement 6. Securing the suspect’s statement The investigator must make sure that he has The investigator must make sure that he has understood the suspect correctly; repeating the understood the suspect correctly; repeating the suspect’s statement, having the suspect correct any suspect’s statement, having the suspect correct any misunderstandings etcmisunderstandings etc

The SUE technique: A training The SUE technique: A training study (I)study (I)

Police Academy in Sweden Police Academy in Sweden

Phase 1:Phase 1:Interrogators (N = 82, police Interrogators (N = 82, police trainees):trainees):Half received training in the SUE Half received training in the SUE technique (theoretical understanding, technique (theoretical understanding, video-material, hands-on training)video-material, hands-on training)Half received no training Half received no training

The SUE technique: A training The SUE technique: A training study (II)study (II)

Phase 2:Phase 2:Each interrogator interviewed one Each interrogator interviewed one mock-suspect (half of the suspects mock-suspect (half of the suspects were guilty to a theft, half were were guilty to a theft, half were innocent).innocent).

Trained and untrained interrogators Trained and untrained interrogators had the exact same case-file to use had the exact same case-file to use for planning the interrogationfor planning the interrogation(the case file contained evidence (the case file contained evidence against the suspect)against the suspect)

The SUE technique: A training The SUE technique: A training study (III)study (III)

The Result:The Result:

The trained group interrogated in line with The trained group interrogated in line with the SUE technique. That is, they…the SUE technique. That is, they…

Did not disclose the evidence earlyDid not disclose the evidence early Did ask for a free recallDid ask for a free recall Did ask specific questions addressing the Did ask specific questions addressing the

evidence, without disclosing the evidenceevidence, without disclosing the evidence Confronted guilty (but not innocent) Confronted guilty (but not innocent)

suspects with the evidence, at the end of suspects with the evidence, at the end of the interrogationthe interrogation

The SUE technique: A training The SUE technique: A training study (IV)study (IV)

The Result:The Result:

Differences between guilty and innocent Differences between guilty and innocent suspects…suspects…

Guilty suspects avoided to mention ‘self-Guilty suspects avoided to mention ‘self-incriminating information’ during the free incriminating information’ during the free recall (innocent suspects did not)recall (innocent suspects did not)

Guilty suspects denied holding ‘self-Guilty suspects denied holding ‘self-incriminating information’ when asked incriminating information’ when asked specific questions (innocent suspects did specific questions (innocent suspects did not)not)

The SUE technique: A training The SUE technique: A training study (V)study (V)

Consequence:Consequence:

Guilty suspects interrogated by Guilty suspects interrogated by trained interrogators showed trained interrogators showed higher statement-evidence higher statement-evidence inconsistencyinconsistency, than did guilty , than did guilty suspects interrogated by suspects interrogated by untrained interrogatorsuntrained interrogators

The SUE technique: A training The SUE technique: A training study (VI)study (VI)

The Results:The Results:

Trained interrogators relied more on Trained interrogators relied more on suspects’ verbal behaviour when suspects’ verbal behaviour when assessing veracity, than did untrained assessing veracity, than did untrained interrogatorsinterrogators

Untrained interrogators ‘burned’ the Untrained interrogators ‘burned’ the evidence early on, and then had to resort evidence early on, and then had to resort to non-verbal cues (non-diagnostic) in to non-verbal cues (non-diagnostic) in order to decide upon veracityorder to decide upon veracity

The SUE technique: A training The SUE technique: A training study (VII)study (VII)

Deception detection accuracy:Deception detection accuracy: Trained interrogators: Trained interrogators: 85.4 %85.4 % Untrained interrogators: Untrained interrogators: 56.1 56.1

%%

Limitations (I) Limitations (I) Obviously, the SUE-technique leaves no Obviously, the SUE-technique leaves no

guarantee that a particular assessment of guarantee that a particular assessment of veracity will be correctveracity will be correct

It is a technique under developmentIt is a technique under development

SUE-technique is not just about withholding SUE-technique is not just about withholding the evidence the evidence

It is a systematic approach with respect to It is a systematic approach with respect to the alternative explanations that the (guilty) the alternative explanations that the (guilty) suspect might offer with respect to the suspect might offer with respect to the evidenceevidence

Limitations (II)Limitations (II) Several possible limitations of the Several possible limitations of the

SUE-technique must be addressed…SUE-technique must be addressed…

1) innocent suspects might show 1) innocent suspects might show ‘statement-evidence inconsistency’ ‘statement-evidence inconsistency’ due to memory factors, or decide that due to memory factors, or decide that the best way out is not to tell the truththe best way out is not to tell the truth

2) 2) how the effectiveness of the how the effectiveness of the technique is affected by the technique is affected by the complexity of the case material, and a complexity of the case material, and a ’step-by-step’ disclosure ’step-by-step’ disclosure

Limitations (III)Limitations (III)

Issue raised: guilty suspects Issue raised: guilty suspects might decide to stay very close to might decide to stay very close to the truth, and therefore show a the truth, and therefore show a high degree of ‘statement-high degree of ‘statement-evidence consistency’evidence consistency’

Data on ex-criminals’ strategies Data on ex-criminals’ strategies argue against this critique (they argue against this critique (they stayed far away from the truth)stayed far away from the truth)

Conclusions (I)Conclusions (I)

The SUE-technique is potent because it The SUE-technique is potent because it draws on the fact that guilty and draws on the fact that guilty and innocent suspects… innocent suspects…

(a) entertain different mental states, and (a) entertain different mental states, and therefore …therefore …

(b) resort to different strategies, and (b) resort to different strategies, and therefore …therefore …

(c) respond differently with respect to the (c) respond differently with respect to the potentially incriminating informationpotentially incriminating information

Conclusions (II)Conclusions (II)

Obvious that one should use the SUE-Obvious that one should use the SUE-technique (or something similar) technique (or something similar) when interviewing suspects?when interviewing suspects?

““Do you interview suspects in a Do you interview suspects in a strategic manner?”strategic manner?”

Conclusions (III)Conclusions (III)

- The untrained police trainees did - The untrained police trainees did notnot use the SUE-technique (or something use the SUE-technique (or something similar)similar)

- Experienced police and customs - Experienced police and customs officers do not seem to use the SUE officers do not seem to use the SUE technique on a regular basistechnique on a regular basis

- Interrogation manuals recommend - Interrogation manuals recommend confrontation in order to ‘win the war’. confrontation in order to ‘win the war’.

Poe & Poe & The purloined The purloined letterletter……

……as the Minister knew that the police as the Minister knew that the police would search his home for the stolen would search his home for the stolen letter, he decided not to hide it. letter, he decided not to hide it.

He simply nailed it to a board on the He simply nailed it to a board on the wall, holding some other papers. wall, holding some other papers.

The letter was fully visible – but not The letter was fully visible – but not easily found by those searching for easily found by those searching for something hidden.something hidden.

Scottish Institute for Policing Research (SIPR) Evidence & Investigation Network Seminar, University of Aberdeen February 18, 2009 Deception Detection.

Documents

clever minister slide

truth research

little research slide

innocence slide

parisian police

empirical research

research b

truthtellers strategies