Scottish Institute for Policing Research (SIPR) Evidence & Investigation Network Seminar, University of Aberdeen Feb

1. Scottish Institute for Policing Research (SIPR)Evidence & Investigation NetworkSeminar, University of AberdeenFebruary 18, 2009 Deception Detection via Strategic Disclosure of Evidence Pär Anders Granhag Department of Psychology University of Gothenburg Sweden pag@psy.gu.se

2. Background (1) • To be able to correctly assess veracity is key in legal contexts • There are many views on how to best detect deception and truth • Research shows that people are not very good at this task (Vrij, 2008)

3. Background (2) • A person trying to detect deception can face one of two situations; (a) where there is no evidence speaking to the suspect’s guilt (very much research) (b) where there is some evidence (information) speaking to the guilt of the suspect (very little research)

4. Background (3) Traditional research on deception… - No background info - No interaction between interviewer and suspect (assess short video clips)

5. Points of departure • Previous research has neglected… …innocent and guilty suspects’ strategies …the information (evidence) speaking to the suspect’s guilt … how the use (misuse) of this information can affect deception detection accuracy

6. General aims • … a brief review of theoretical notions relevant for liars’ and truth-tellers’ strategies • … review empirical research on suspects’ counter-interrogation strategies • … show that knowledge about liars’ and truth-tellers’ strategies can be used to increase deception detection accuracy

7. Theoretical part – Aim: • Provide a theoretical framework resting upon psychological notions from three domains: 1. The psychology of instrumental mind-reading 2. The psychology of self-regulation 3. The psychology of guilt and innocence

8. Mindreading: Background (1) * Edgar Allan Poe (1809-1849), father of the modern detective story * Alter ego, Detective Auguste Dupin * The Purloined Letter * Story about a stolen letter, hidden by a clever Minister

9. Mindreading: Background (2) The Parisian Police searched the Minister’s house for months in order to find the letter, but without success. They looked for secret drawers, probed all cushions with fine long needles, examined legs in the furniture for cavities, and searched the grounds around the house.

10. Mindreading: Background (3) • Dupin (Poe) attributes the Parisian Police’s failure to: ”ill-admeasurement, or rather through non-admeasurement, of the intellect with which they are engaged.” ”They consider only their own ideas of ingenuity and, in searching for something hidden, advert only to the modes in which they would have hidden the letter.”

11. Mindreading: Background (4) • The police failed to mindread the Minister, whereas the Minister performed a mind reading of the police. • Hence, the Minister was able to predict the actions taken by the police in order to try to find the stolen letter, whereas the police failed to reconstruct the actions taken by the Minister in order to hide it

12. Mindreading: Background (5) • Poe draws our attention to why this case was so difficult to solve: (a) the police spent too much time thinking about their own strategies (b) their reasoning was biased by projection (false consensus) and stereotypical thinking

13. Mindreading: Definition (I) • The cornerstone of simulating the mind of another person (‘mindreading’) is that one imagines oneself being in the other person’s situation, which will trigger processes that are similar to those of the other (Malle & Hodge, 2005) • We practice ‘mindreading’ on a daily basis “I can imagine how you must feel” “I guess you need a drink?”

14. Mindreading: Defintion (II) • The term ‘mindreading’ is used in an instrumental manner, to predict future behaviour. …not in a descriptive manner, trying to read the actual content of a person’s mind (“The number you are thinking of is four!”).

15. The goal of instrumental mindreading: To improve the ability to predict other people’s behaviour

16. Traps when reading minds (I) • First, there are many reasons why interrogators may neglect the ‘mind of the suspect’. For example, a) too occupied thinking about their own tactics b) too eager to get a confession c) overconfident in their own ability to detect deception d) lack principles for strategically using the critical information at hand

17. Traps when reading minds (II) • Second, interrogators may go wrong due to biases like… Projection (false consensus) = The interrogator assumes that the suspect has the same mental states as he/she would have had (being in the same situation), “If someone would present all this evidence, I would surely confess” Stereotyping = The interrogator assumes that the suspect has mental states that correspond to ‘the typical criminal’ “I know this type of…- I will break him by…”

18. Mindreading: Why? • If the interrogator is successful in reading the mind of the suspect, then he or she can … a) …more accurately predict the suspect’s behaviour b) …use these predictions to better plan and conduct the interrogation

19. Mindreading: How? • Our mindreading ability can be improved if utilizing psychological theory on fundamental human behaviour and reasoning • The psychology of self-regulation

20. The Psychology of Self-regulation (I) • Self-regulation refers to ways in which people control their behaviour (e.g., Fiske & Taylor, 2008) • Self-regulatory strategies are particularly primed by threatening situations • A person anticipating a threat will have a number of self-regulative methods to choose from • The common objective of these methods is to try to restore control

21. The Psychology of Self-regulation (II) • Decision control; refers to the sense of control achieved when making a decision with respect to how to engage in a forthcoming aversive event • Translated to crime suspects; decision control aims at reducing threat by deciding on how to act duríng the upcoming interview (counter-interrogation strategies)

22. The Psychology of Self-regulation (III) • Both guilty and innocent suspects will view a upcoming interrogation as a threat; this threat will evoke self-regulative strategies • Both guilty and innocent suspects want to change the interviewer’s attitude from suspicious to non-suspicious

23. Theoretical framework 1. The psychology of instrumental mind-reading 2. The psychology of self-regulation 3. The psychology of guilt and innocence

24. The psychology of guilt (I) • Guilty suspects often hold exclusive knowledge about the crime; this knowledge can – of course - be incriminating • This self-incriminating knowledge can be construed as a threat (an aversive stimulus) • In brief, the threat for a guilty suspect is that the interviewer may come to know what he knows

25. The psychology of guilt (II) Guilty suspects’ decision control: • Have to decide upon what to admit, avoid and deny • One basic counter-interrogation strategy; it makes little sense to avoid or deny what the suspect believe the interviewer to already know

26. The psychology of guilt (III) • Decision control is particularly critical with respect to the incriminating information which the suspect is uncertain whether or not the interviewer holds • Basically, two strategies: Avoidance (not to mention, e.g. visiting a certain place at a certain time) Denial (denying, e.g. being at a certain place at a certain time)

27. The psychology of innocence (I) • Innocent suspects’ decision control iscoloured by… A belief in a just world; people will get what they deserve, and deserve what they get (Lerner, 1980) The illusion of transparency; their inner feelings/ mental states will manifest themselves on the outside (Savitsky & Gilovich, 2003)

28. The psychology of innocence (II) • Many innocent suspects will decide to ‘tell it like it was’, and trust that ‘their innocence will shine through’ (Kassin, 2005) • Innocent (mock) suspects found to be more likely to waive their rights to silence, and cooperate during investigations (Kassin, 2005)

29. The psychology of guilt and innocence (I) • Guilty and innocent suspects have the same goal; to be perceived as innocent • They may use the same major self-regulatory method to reach this goal; decision control

30. The psychology of guilt and innocence (II) • Guilty suspects’ decision control is assumed to be influenced by aversion, which will result in avoidant strategies • Innocent suspects’ decision control is assumed to be influenced by the belief in a just world and/or the illusion of transparency, which will result in much less avoidant strategies

31. Empirical part: Briefly review research on guilty and innocent suspects’ counter-interrogation strategies

32. Guilty suspects’ counter-interrogation strategies (I) • Empirical work show that… … a majority of guilty mock-suspects report to have a strategy when facing a police interview …guilty mock-suspects tend to put their strategies to work during the interrogation

33. Guilty suspects’ counter-interrogation strategies (II) … guilty mock-suspects, if given the opportunity, tend to avoid mentioning the critical information … guilty mock-suspects, if deprived of avoidance as a way out, tend to deny that they hold incriminating knowledge.

34. Guilty suspects’ counter-interrogation strategies (III) • New empirical study on how… (a) interrogators’ degree of suspicion and (b) suspects’ past criminal record …affect guilty mock-suspects’ disclosure of crime-relevant information (Granhag, Clemens & Strömwall, 2009)

35. Guilty suspects’ counter-interrogation strategies (IV) • Participants: 45 students 45 ex-criminals • Ex-criminals recruited via a wide-spread national organization (KRIS), helping ex-criminals finding their way back to a non-criminal life

36. Guilty suspects’ counter-interrogation strategies (V) • None of the students reported to have been interviewed by the police • All ex-criminals had been interviewed by the police, and all of them reported to have lied in police interviews

37. Guilty suspects’ counter-interrogation strategies (VI) Procedure: • All mock-suspects had to imagine that they had stolen money from a store in a shopping center, and that they now faced a police interview (only guilty suspects) • Half of the ex-criminals and half of the students were told that they were under a high degree of suspicion (vs. low)

38. Guilty suspects’ counter-interrogation strategies (Vii) Procedure: • All mock-suspects were asked about their counter-interrogation strategies • Specifically, what to disclose in the ’free recall phase’ of the interrogation, and what to disclose in response to more directed/specific questions

39. Guilty suspects’ counter-interrogation strategies (Vii)

40. Guilty suspects’ counter-interrogation strategies (8) • Students disclosed significantly more (incriminating) information than did the ex-criminals • Under high (vs. low) level of suspicion students disclosed more information, whereas ex-criminals disclosed less information

41. Guilty suspects’ counter-interrogation strategies (8) • Under a high degree of suspicion naive (vs. experienced) mock-suspects seem to look differently upon the ’burden of proof’: • Naive mock-suspects take on the burden, and are more willing to talk (co-operate) - Experienced mock-suspects hand over the burden to the police, and are less willing to talk (co-operate)

42. Guilty suspects’ counter-interrogation strategies (9) • What can we learn from these results? 1) Raise some doubt with respect to using students as mock-suspects for certain deception experiments 2) Implications for strategic disclosure of evidence

43. Innocent suspects’ counter-interrogation strategies (1) • … significantly fewer innocent (than guilty) mock-suspects report to bring a strategy into the interview room • … very few innocent mock-suspects tend to avoid mentioning or deny holding the potentially incriminating information

44. Innocent suspects’ counter-interrogation strategies (2) … the principal ‘strategy’ among innocent suspects seems to be to ‘to keep the story real’ and ‘to tell the truth like it happened’ (Hartwig et al, 2007). … innocent (vs. guilty) suspects are more prone to waive their constitutional rights to silence and agree to be interrogated. Based on that they have nothing to hide, and that they believe that the truth will come out (Kassin & Norwick, 2004)

45. Suspects’ counter-interrogation strategies: Summing up • Suspects’ counter-interrogation strategies are moderated by a number of different factors, such as… • Mind-set (guilty vs. innocent) • Background (criminal vs. non-criminal) • Level of suspicion (high vs. low) • Interview technique (confrontational vs. strategic) • Type of crime (deny act vs. deny intent)

46. From empirical work to interview tactics (I) • The combined empirical evidence support the basic assumptions that.. • a suspect’s strategy is a reflection of his or her mental state (b) a suspect’s behaviour is a reflection of his or her strategy

47. From empirical work to interview tactics (II) • We know that many guilty suspects avoid and/or deny holding potentially incriminating information; and that innocent suspects tend to believe that the ‘truth will shine through’. • But how do these findings translate into an interview technique (tactic)?

48. Investigators’ interrogation strategies (1) • What do we know about how professional investigators disclose the evidence (critical information) when interrogating suspects?

49. Investigators’ interrogation strategies (2) • Sources of information: - Recommendations from interview/interrogation manuals - Studies using real-life material - Experimental research

50. Investigators’ interrogation strategies (3) • Interrogation manuals are either silent on how to use the available evidence (e.g. Gordon & Fleisher, 2002), or recommend that the interrogation is started by confronting the suspect with the evidence (e.g. Inbau et al., 2001; Yeschke, 1997)