This post is an abstract of my Master 1 thesis about a new technique of interview to detect deception.
Key words : a lie, interview, verifiable details, second narrative.
Professionals demand methods allowing them to distinguish lie from truth during an interview with a person. This study aims at helping professionals in their practice by developing a new technique of intra-subject interview enables to discriminate a deceitful testimony from a sincere one.
Theoretical framework and hypotheses
It is not enough to use a tool of detection, to detect deception. Indeed, the major part of the work is the interview. In this study, we try to develop a new technique of interview enabling the differentiation between a deceitful testimony and a sincere one. We based our protocole on several existing techniques of interview in literature: the cognitive interview, the verifiability approach and the information protocol.
The cognitive interview
This technique of interview consists in proposing several narratives to the participant in order to facilitate the recall of the information. One of the instructions proposed by Py and al. (2001) is the instruction of peripheral focus. The authors noticed thanks to the observations of interviews with witnesses, that over the first narrative people tell only the main actions of the scene. In fact, it requires too much a cognitive effort to people to evoke in the same narrative both the main actions and all the details surrounding them (Demarchi and Py, 2006).
A second narrative is thus useful to gain this information. It is what suggests the instruction of peripheral focus. It asks the participant to remind at the same time the actions of the event, but also, all the details surrounding the scene. We suggest to the interviewee to make “freeze frames” to help him restore his narrative. Overall, telling the same narrative twice, brings the subject to give more details in the second narrative.
We make the hypothesis that a liar will have difficulty in giving more details in a second narrative, compared to a sincere person. Indeed, the storyteller will describe an invented narrative and therefore he will not have access to all the available sensory and contextual details in his external storage (Johnson and al .,1981).
The verifiability approach and the information protocol
The Verifiability Approach (VA) includes two postulates: First, deceivers believe that ” the wealth of details ” is often used to estimate the credibility of a narrative. Therefore, when a person provides many details in a statement, it will rather tend to be judged as credible. It’s because of this belief that liars have a motive to provide a very detailed narrative to appear honest.
Secondly, unlike the sincere people who can freely give verifiable details, deceivers prefer to avoid providing them. They are afraid that the investigators will verify the information and confound them by putting them in front of the contradictions between their statements and the factual elements (Harvey, Has. C., Vrij, Has.Nahari, G., and Ludwig, K., 2016). These authors thus postulate that storytellers are in a dilemma of management of the information: at first they are motivated to provide many details in order to maximize the chances of being trusted, and at the same time, they are willing to hold details to minimize the risk of being taken.
The information protocol postulates that if participants are informed that the investigator intends to verify the elements of their statements, there will be a difference in the number of verifiable details provided by liars and sincere people (Nahari and al ., 2014b).
On the basis of the works of these authors, we assume that deceivers will give fewer verifiable details than sincere people when the information protocol is used.
The objective of our study is to use and compare the results of these techniques in order to find a framework for interviews that will help investigators in their practice to discern the sincere statements from the deceitful statements. We based our work on a study which take over the information protocol and the verifiability approach (Nahari, Vrij and Fisher, 2014).
Method
A total of 80 participants was recruited (40 liars and 40 sincere people). In order to bring half of the subjects to provide a deceitful statement, a fictitious robbery was set up on the campus of the University of Toulouse II Jean Jaurès. The statements were collected by means of interviews, suggesting four different instructions based on a technique with two narratives: two simple narratives (condition 1, as control), a simple narrative and an instruction of peripheral focus derived from the cognitive interview (condition 2), a simple narrative followed by the verifiability approach and by the information protocol (condition 3) and two narratives based on the verifiability approach and the information protocol (condition 4).
Participants were uniformly distributed between 8 units: Status (truth / lie) x Condition (1/2/3/4) and narratives were analyzed in terms of number of verifiable details and total number of details (verifiable and not verifiable).
Main results and discussion
Our results firstly show that participants overall give further details in a second narrative that in the first narrative. More specifically, sincere people give more details in a second narrative than storytellers.
The results also show that the subjects give significantly more details in the second narrative with an instruction of peripheral focus.
Moreover, we can notice from our results that the second narrative enables to differenciate between sincere people (who give significantly more details) and liars.
However, the interaction Account*Statut*Instructions was not significant for the total sum of details.
Finally, only the 3rd condition indicated a significant interaction Status x Narrative on the number of verifiable details provided, sincere people giving more verifiable details during the second narrative than deceivers compared with their first narrative. The results actually pointed out that in the 3rd condition, the evolution of the number of verifiable details between narrative 1 (N1) and the narrative 2 (N2) was significantly different according to the status of the participant. In fact, the number of verifiable details decreases for liars between N1 and N2, while it increases significantly between N1 and N2 for sincere people.
Conclusion
In conclusion, to help professionals in their practice, we can suggest them a technique of interview in two narratives (simple then verifiable, as in our 3rd condition) which would enable to discriminate between sincere people and deceivers, by analyzing the number of new verifiable details provided in the second narrative.
However, our results are debatable. The lie is a difficult component to manipulate in laboratory. Few studies set up an experimental situation where the subject tell a real lie. In spite of the settings of interviews as close as those of a police interrogation (camera, clip-on microphone), the information protocol does not seem adapted to the university framework. There is a possibility that the participants were skeptical about the actual check of their statement. That is why the results of our study need to be taken with caution and some thought must be given to the application of this study in professional environment is advised.
Word I have learn :
- Narrative = un récit
- Framework = contexte
- Uniformly distributed = équiréparti
- Debatable = discutable
- Deceiver / Storyteller = un menteur
Bibliography Demarchi, S., & Py, J. (2006). L’entretien cognitif: son efficacité, son application et ses spécificités. Revue québécoise de psychologie, 27(3), 1-20. Harvey, A. C., Vrij, A., Nahari, G., & Ludwig, K. (2017). Applying the Verifiability Approach to insurance claims settings: Exploring the effect of the information protocol. Legal and Criminological Psychology, 22(1), 47-59. Johnson, M. K., & Raye, C. L. (1981). Reality monitoring. Psychological Review, 88(1), 67-85 Nahari, G., Vrij, A., & Fisher, R. P. (2014a). Exploiting liars' verbal strategies by examining the verifiability of details. Legal and Criminological Psychology, 19(2), 227-239. Nahari, G., Vrij, A., &Fisher, R. P. (2014b). The verifiability approach: Countermeasures facilitate its ability to discriminate between truths and lies. Applied Cognitive Psychology, 28, 122–128.doi:10.1002/acp.297 Py, J., Ginet, M., Demarchi, S. et Ansanay-Alex, C. (2001). Une démarche psychosociale d’évaluation des procédures d’instructions. Mission de Recherche Droit et Justice, Ministère de la Justice.
Student in I/O Psychology