objective cues to deception shows that behavioural ... line an interview technique (the SUE tech- nique) which ... Research tells us that many guilty suspects.
The SUE technique: The way to interview to detect deception Pär Anders Granhag, Leif A. Strömwal & Maria Hartwig
such as criminal investigators, custom officers and security personnel frequently face the task of assessing people’s veracity, be it a suspect protesting his innocence, a passenger claiming to have nothing to declare or a nervous man with a rucksack entering a crowded railway station. To be able to discriminate between truthful and deceptive persons may be of acute importance. About four decades of research paints a rather gloomy picture of people’s deception detection ability (Vrij, 2000). In fact, people perform just above the level of chance when trying to discriminate between truth and deceit (Bond & DePaulo, in press). In addition, a meta-analysis on objective cues to deception shows that behavioural differences between liars and truth-tellers are very few and small (DePaulo et al., 2003). On a more positive note, it is possible to identify a paradigmatic shift in research focus from studies mainly concerned with measuring people’s ability to detect deception, to research programmes aiming at enhancing people’s deception detection performance (Granhag & Strömwall, 2004; Granhag & Vrij, 2005). In this article we will present a selection of findings from one such programme. This programme begins from the fact that lie-catchers often have some potentially incriminating information against a person who is to be interviewed, but that (a) there was very little research on how to best use such information during interviews and (b) most interviewing and interrogation manuals were (and still are) silent on the issue.
L
EGAL PROFESSIONALS
Forensic Update 88 – January 2007
The research programme: Detecting deception by Strategic Use of Evidence (SUE) The series of studies conducted within the research programme share several features. We have employed a mock-crime paradigm, where half of the participants commit a mock-crime and half commit no such crime. Hence, we have both guilty and innocent suspects. All suspects are then interviewed; in some of our studies by experienced police officers, in others by police trainees or trained experimenters. Importantly, for each suspect there is some potentially incriminating information indicating his or her guilt, but this information does not preclude that the suspect is in fact innocent (and that the ‘crime’ was conducted by another person). To date, we have conducted six empirical studies and below we provide some of the key findings. We will first summarise the results on the differences between guilty and innocents suspects’ strategies, and then outline an interview technique (the SUE technique) which suggests how potentially incriminating information can be used strategically. Finally, we describe studies in which the SUE technique has been empirically tested.
Guilty suspects’ strategies In a survey study of criminals’ beliefs we found that they believed that planning the behaviour is valuable in lying successfully (Granhag et al., 2004). We have also found that a majority of mock-suspects reported to have a pre-interview strategy when facing a police interview (Hartwig, Granhag & Strömwall, in press). Importantly, our research programme strongly suggests that guilty 25
Pär Anders Granhag, Leif A. Strömwal & Maria Hartwig mock-suspects will (a) (if given the opportunity) avoid mentioning possibly incriminating information during an interview, and (b) (if deprived of the avoidance alternative) deny that they hold the incriminating knowledge (Hartwig et al., 2005, Hartwig et al., in press; Granhag et al., 2006). Interestingly, these findings fit neatly with what is known about some of the most basic forms of human behaviour. Research on aversive conditioning has found an avoidance response (to try to prevent confrontation with a threatening stimulus) and an escape response (to try to terminate a direct threat). In short, a guilty suspect’s behaviour is not much different than a (not yet spotted) person trying to avoid a tiger, or a (already spotted) person trying to escape the tiger.
Innocent suspects’ strategies We found that significantly fewer innocent (than guilty) mock-suspects reported to bring a strategy into the interview room (Hartwig et al., in press a). In addition, very few of our innocent mock suspects tended to avoid or escape the potentially incriminating information (Hartwig et al., in press; Granhag et al., 2006). Rather, they could be expected to volunteer such information. In previous studies, it has been found that the main ‘strategy’ among the innocent suspects was ‘to keep the story real’ (Strömwall, Hartwig & Granhag, 2006) and ‘to tell the truth like it happened’ (Hartwig et al., in press a). That innocent suspects’ trust the ‘truth to shine through’, and therefore feel little need for a strategy, is in accord with well-established cognitive biases such as ‘people will get what they deserve, and deserve what they get’ (belief in a just world; Lerner, 1980), and ‘one’s inner feelings will manifest themselves on the outside’ (illusion of transparency; Gilovich, Savitsky & Medvec, 1998). Innocent people’s beliefs are evident in several situations (for more on the psychology of innocence, see Kassin, 2005).
From empirical findings to interview tactics Research tells us that many guilty suspects avoid and escape confrontation with incrim26
inating information, while innocent suspects tend to volunteer such information. But how do these findings translate into an effective interview technique? Recently, we outlined and tested the Strategic Use of Evidence technique (the SUE technique), and below we describe the basic phases of this technique. The purpose is to illustrate how suspects’ strategies can be used during an interview, not to supply a manual in the SUE technique. 1. Planning of the interview. Investigators need to carefully work through the case file and identify pieces of potentially incriminating information. They should especially search for information that the suspect will not know for certain that the investigator possesses. They also need to formulate questions (both open ended and specific) addressing these pieces of potentially incriminating information (see phase 3). 2. Informing the suspect. In accordance with the relevant codes of practice, the investigator should inform the suspect about the type of crime he is suspected of having committed and communicate information about his rights etc. Obviously, the investigator should also ask the suspect about his standpoint on the suspicions. However, it is important that the investigator, at this stage, does not disclose any of the potentially incriminating information to the suspect. 3. The free recall phase. The investigator should encourage the suspect to give a free recall. For example: ‘If you indeed are innocent, I have no interest in keeping you here. But to help you get out of this place – you need to help me. You can do this by telling me what happened last Saturday, where you were, what you did etc.’ 4. The question phase. After the free recall the investigator should ask questions of which some address the potentially incriminating information. That is, that the investigator actually knows the correct answer to some of the questions asked. It is crucial that the nature of these questions does still not reveal what the investigator knows. 5. Securing the suspect’s statement. The investigator must make sure that he or she Forensic Update 88 – January 2007
The SUE technique has understood the suspect correctly. This could be done by carefully repeating the suspect’s statement, and having the suspect correct any misunderstandings etc. For example: ‘Is it correct that you have never visited Café Roma at University Avenue?’; ‘OK, but I just want to make sure. Is there no way your memory has let you down on this one?’ In short, it is important that the investigator makes the suspect commit to his statement. 6. Matching the statement and the incriminating information. If there are obvious inconsistencies between the suspect’s statement and the incriminating information held by the investigator, the suspect might be asked to explain these. This phase is very delicate as there are many factors that need to be considered when deciding on if (and if, how) the potentially incriminating information should be disclosed to the suspect. Importantly, if the potentially incriminating information (evidence) is used in a strategic manner – as suggested by the SUE technique – the following two predictions can be made. First, guilty suspects will tell a story that, on one or several occasions, contradicts what the interviewer knows. That is, it will be possible to identify some (or several) statement-evidence inconsistencies. Second, innocent suspects can be expected to tell a story consistent with what the interviewer knows. That is, there will be a high degree of statement-evidence consistency. Thus, the degree of statement-evidence consistency can be expected to be a relatively reliable cue to deception and truth.
Training to detect deception via the SUE-technique In order to test the SUE-technique empirically, a training study was conducted at a police academy in Sweden (Hartwig et al., in press). Half of the police trainees (n = 41) received training in interviewing according to the SUE technique, whereas the other half received no training (n = 41) and interviewed as they wished. Half of the suspects committed a mock-theft by stealing a wallet from a Forensic Update 88 – January 2007
briefcase in a bookstore on campus (guilty suspects, n = 41, whereas the other half visited the same bookstore without committing any theft (innocent suspects, n = 41). All police trainees were allowed time to prepare the interview, and given a case-file containing potentially incriminating information against the suspect: ■ a witnesses claiming to have seen the suspect enter the bookstore; ■ a witness claiming to have seen the suspect in the store; and ■ the result of a technical analysis showing the suspect’s fingerprints on the briefcase. This information was ‘true’ for all suspects; all guilty suspects had to touch the briefcase in order to steal the wallet, and all innocent suspects had to touch the briefcase in order to search for a particular book. Analyses of the interviews showed that trained interviewers (a) refrained from starting the interview by disclosing any potentially incriminating information, (b) asked the suspect for a free recall, (c) asked questions that addressed the incriminating information, and (d) at the end of the interview asked guilty suspects to explain the statement-evidence inconsistencies. Hence, the trained interviewers interviewed in line with the SUE technique. We found that guilty suspects both avoided mentioning incriminating information during the free recall, and escaped (denied holding) incriminating information when asked specific questions that addressed this particular information. In contrast, innocent suspects were found to show much less avoidance and escape. Guilty and innocent suspects thus differed in terms of statementevidence consistency. Importantly, guilty suspects interviewed by trained interviewers showed higher statement-evidence inconsistency than did guilty suspects interviewed by untrained interviewers. In short, the trained (but not the untrained) interviewers managed to create and use a diagnostic cue to deception: statement-evidence inconsistency. Trained interviewers achieved an unprece27
Pär Anders Granhag, Leif A. Strömwal & Maria Hartwig dented accuracy score of 85.4 per cent, whereas the untrained achieved a score of 56.1 per cent.
Summing up In contrast to previous research on deception detection, our research programme warrants some optimism. If interviewers learn to use potentially incriminating information strategically they will enhance their ability to detect deception. In essence, the SUE technique works because it draws on both guilty and innocent suspects’ strategies. Note also that the prerequisite for employing the technique is not that the interviewer’s total knowledge about the crime exceeds that of the suspect, only that the suspect is uncertain about what the interviewer actually knows (which is a very common situation). Furthermore, the technique stands in sharp contrast to ‘confrontational interrogation techniques’, such as, for example, the Reid Technique (Inbau et al., 2001). Instead, the SUE technique is to be sorted into the broad category of ‘information-gathering interviewing techniques’ (Vrij, 2003). It should, however, be acknowledged that the SUE-technique also differs from the techniques in this category, in that its ultimate goal is not to gather as much information as
possible. That is, the key is not the amount of information per se, but what suspects choose to report and not to report. At first sight it may seem obvious that something similar to the SUE-technique should be used when interviewing suspects. But before dismissing the technique as trivial, one should consider the following: First, the untrained police trainees were highly motivated to succeed, but did not use something even similar to the SUE-technique (Hartwig et al, in press). Second, research shows that not even experienced police officers handle the potentially incriminating information strategically (Hartwig et al., 2004). Third, archival studies show that the potentially incriminating information (evidence) sometimes is disclosed already at the outset of the interview (e.g. Leo, 1996). Finally, we believe to have sketched a new paradigm for studying the detection of deception. The first series of studies has been conducted, but the paradigm obviously offers and needs future explorations.
Affiliations Pär Anders Granhag & Leif A. Strömwall: Department of Psychology Göteborg University Maria Hartwig: John Jay College of Criminal Justice, City University of New York
References Bond, C.F. & DePaulo, B.M. (in press). Accuracy of deception judgments. Personality and Social Psychology Review. DePaulo, B.M., Lidsay, J.J., Malone, B.E., Muhlenbruck, L., Charlton, K. & Cooper, H. (2003). Cues to deception. Psychological Bulletin, 129, 74–118. Gilovich, T., Savitsky, K., Medvec, V.H. (1998). The illusion of transparency: Biased assessments of others’ ability read one’s emotional states. Journal of Personality and Social Psychology, 75, 332–346. Granhag, P.A. & Vrij, A. (2005). Detecting deception. In N. Brewer, & K. Williams (Eds.). Psychology and Law: An empirical perspective (pp. 43-92). New York: Guilford Press. Granhag, P.A. & Strömwall, L.A. (Eds.) (2004). The detection of deception in forensic contexts. Cambridge: Cambridge University Press.
28
Granhag, P.A., Andersson, L.O., Strömwall, L.A. & Hartwig, M. (2004). Imprisoned knowledge: Criminals’ beliefs about deception. Legal and Criminological Psychology, 9, 103–119. Granhag, P.A., Hartwig, M., Wolf, A., Strömwall, L.A. & Vrij, A. (2006). Suspects’ strategies as a function of guilt and interrogation style. Manuscript under preparation. Hartwig, M., Granhag, P.A. & Vrij, A. (2005). Police interrogation from a social psychology perspective. Policing and Society, 15, 401–421. Hartwig, M. (2005). Interrogating to detect deception and truth: Effects of strategic use of evidence. PhD dissertation, Department of psychology, Gothenburg, University, Sweden. Hartwig, M., Granhag, P.A., Strömwall, L.A. & Vrij, A. (2005). Detecting deception via strategic disclo-
Forensic Update 88 – January 2007
The SUE technique sure of evidence. Law and Human Behavior, 29, 469–484. Hartwig, M., Granhag, P.A., Strömwall, L.A. & Kronkvist, O. (in press). Strategic use of evidence during police interviews: When training to detect deception works. Law and Human Behavior. Hartwig, M., Granhag, P.A. & Strömwall, L.A. (in press). Guilty and innocent suspects’ strategies during police interrogations. Psychology, Crime & Law. Hartwig, M., Granhag, P.A., Strömwall, L.A. & Vrij, A. (2004). Police officers’ lie detection accuracy: Interrogating freely versus observing video. Police Quarterly, 7, 429–456. Inbau, F.E., Reid, J.E., Buckley, J.P. & Jayne, B.C. (2001). Criminal interrogation and confessions. Gaithersburg, MD: Aspen Publishers. Kassin, S.M. (2005). On the psychology of confessions: Does innocence put innocent at risk? American Psychologist, 60, 215–228.
Leo, R.A. (1996). Inside the interrogation room. Journal of Criminal Law and Criminology, 86, 266–303. Lerner, M.J. (1980). The belief in a just world. New York: Plenum. Strömwall, L. A., Hartwig, M., & Granhag, P. A. (2006). To act truthfully: Nonverbal behavior and strategies during a police interrogation. Psychology, Crime & Law, 12, 207–219. Vrij, A., Fisher, R., Mann, S. & Leal, S. (2006). Detecting deception by manipulating cognitive load. Trends in Cognitive Science, 10, 141–142. Vrij, A. (2003). We will protect your wife and child, but only if you confess. In P.J. van Koppen & S.D. Penrod (Eds.). Adversarial versus inquisitorial justice: Psychological perspectives on criminal justice systems (pp. 55–79). New York, NY: Kluwer Academic. Vrij, A. (2000). Detecting lies and deceit: The psychology of lying and implications for professional practice. Chichester: John Wiley.
Submitting articles to Forensic Update We were aware when putting this issue together that we have not included the publication deadlines for some time. We will now be printing this each time for contributors' ease of reference. The following dates for submission of first drafts. These dates give us two months to turn round papers, and subsequently have them returned to us following any suggestions for amendments. October issue 2007 – 15 May January issue 2008 – 15 August The following deadlines are for final drafts to be with the editorial team in time for publication in the next issue. However, we cannot guarantee that an article will be published in the following issue if the deadline is met. We will generally try to publish articles in the order they are received, but we may also need to consider how articles may or may not complement each other. We will endeavour to contact all authors as soon as a decision has been made about the inclusion, or not, of a paper in an issue. Issue October 2007 January 2008
Deadline for submission 15 July 15 October
copies of articles should go to both Geraldine and Glenda; please include a word count and author contact details on each manuscript. Many thanks to all of you who that have contributed to Forensic Update. The Editorial Team
Forensic Update 88 – January 2007
29
