Peter J. van Koppen

A hybrid formal theory of arguments, stories and criminal evidence

This paper presents a theory of reasoning with evidence in order to determine the facts in a criminal case. The focus is on the process of proof, in which the facts of the case are determined, rather than on related legal issues, such as the admissibility of evidence. In the literature, two approaches to reasoning with evidence can be distinguished, one argument-based and one story-based. In an argument-based approach to reasoning with evidence, the reasons for and against the occurrence of an event, e.g., based on witness testimony, are central. In a story-based approach, evidence is evaluated and interpreted from the perspective of the factual stories as they may have occurred in a case, e.g., as they are defended by the prosecution. In this paper, we argue that both arguments and narratives are relevant and useful in the reasoning with and interpretation of evidence. Therefore, a hybrid approach is proposed and formally developed, doing justice to both the argument-based and the narrative-based perspective. By the formalization of the theory and the associated graphical representations, our proposal is the basis for the design of software developed as a tool to make sense of the evidence in complex cases.

The Inconsistent Suspect: A Systematic Review of Different Types of Consistency in Truth Tellers and Liars

Many people believe that inconsistency is a sign of lying, and that consistency is a sign of truth telling. The present chapter assesses the validity of these popular beliefs. We review the literature on the relationship between consistency and deception, and present an overview of effect sizes obtained in studies on this topic. Four different types of consistency are explored, namely: within-statement consistency, between-statement consistency, within-group consistency, and statement-evidence consistency. We also discuss three interview approaches designed to amplify differences between liars and truth tellers—the unanticipated-question approach, the cognitive-load approach, and the Strategic Use of Evidence technique—and examine their impact on different types of consistency. Finally, we identify limitations and gaps in the literature and provide directions for future research.

Public reasons for abolition and retention of the death penalty

This article compares attitudes toward capital punisunent in the United States and in Europe. Views on the death penalty in the Netherlands are discussed, and similarities are drawn with opinions held throughout Western Europe. Data from several nations are compared, and the article examines why some countries retain the death penalty while most do not. The authors conclude that differences across countries may be explained by different political stuctue. Specifically, countries with two political parties are more likely to retain the death penalty than countries with multiple political parties.

Forensic expectations: Investigating a crime scene with prior information.

In a large body of research the influence of contextual information on decisions made in a broad range of disciplines has been studied. To date, the influence of these expectancy effects on the crime scene investigation has not been studied. In the present study we explored the effect of prior information given to crime scene investigators on their perception and interpretation of an ambiguous crime scene. Participants (N=58) were experienced crime scene investigators who were provided with a panoramic photograph of an ambiguous mock crime scene. The victim may have committed suicide or was murdered. Participants either received prior information indicating suicide, prior information indicating a violent death, or they received no prior information. Participants were asked about what they thought had happened at the scene of the crime, both at the initial assessment of the scene and at the end of the investigation when they were asked to describe the most likely scenario. They were also asked which traces they wanted to secure and why. Results showed that participants interpreted the crime scene differently dependent on how it was presented to them. Both the initial assessment of the scene and the most likely scenario that was described after the investigation were influenced by the prior information the participants were provided with, even though roughly the same traces were secured by all, independent of the prior information. Results demonstrate that prior information indeed influences the interpretation of the crime scene, but since the present study was exploratory further research is needed.

Acknowledge, repeat, rephrase, elaborate: Witnesses can help each other remember more

Crimes are often observed by multiple witnesses. Research shows that witnesses can contaminate each others memory, but potential benefits of co-witness discussion have not yet been investigated. We examined whether witnesses can help each other remember, or prune each others errors. In a research design with high ecological validity, attendees of a theatre play were interviewed approximately one week later about a violent scene in the play. The couples that signed up for our study had known each other for 31 years on average. Participants were first interviewed individually and then took part in a collaborative interview. We also included a control condition in which participants took part in two individual interviews. Collaboration did not help witnesses to remember more about the scene, but collaborative pairs made significantly fewer errors than nominal pairs. Further, quantitative and qualitative analyses of retrieval strategies during the discussion revealed that couples who actively acknowledged, repeated, rephrased, and elaborated upon each others statements remembered significantly more information overall. Taken together, our findings suggest that, under certain circumstances, discussion between witnesses is not such a bad idea after all.

When discussion between eyewitnesses helps memory

PurposePolice interviewers are typically instructed to prevent eyewitnesses from talking to each other, because witnesses can contaminate each others memory. Previous research has not fully examined, however, how discussion between witnesses affects correct and incorrect recall of witnessed events. We conducted quantitative and qualitative analyses to explore the influence of co-witness discussion in more detail.MethodsWitnesses were interviewed individually or in pairs about a videotaped violent event. We conducted individual interviews prior to collaboration (to obtain an independent record of what individuals remembered) and after collaboration (to assess whether collaboration subsequently triggered new memories).ResultsPairs that were interviewed together (collaborative pairs) remembered just as much correct information overall as pairs interviewed individually (nominal pairs), but collaborative pairs made significantly fewer errors. We found evidence of retrieval disruption during the discussion (i.e., collaborative pairs omitted significantly more old information during the second interview than nominal pairs) but also of a delayed cross-cuing effect (i.e., collaborative pairs reported significantly more new information in the final interview than nominal pairs). Pairs who used more content-focused retrieval strategies during the discussion (acknowledgements, repetitions, restatements, and elaborations) reported significantly more information.ConclusionsThe current findings suggest that, under certain conditions, discussion between eyewitnesses can help rather than hurt memory. Theoretical and practical implications will be discussed.

A Lie and a Mistress: On Increasing the Believability of Your Alibi

The present study was designed to assess whether or not the presentation method and the salaciousness of an alibi affect its evaluation. Community participants (n = 150) were asked to evaluate the salacious or non-salacious alibi of a crime suspect. The alibi was either presented immediately after arrest by the suspect or was changed after the initial alibi turned out to be incorrect. The incorrect alibi was due to either a misrecollection or a deliberate lie. We found that when the initial alibi was changed into a salacious one, the believability increased. This effect was larger when the initial alibi was a lie than when it was a misrecollection. The results of the present study demonstrate that, contrary to common belief, a changed salacious alibi can lead to an increase in alibi believability.

Observing offenders: Incident reports by surveillance detectives, uniformed police, and civilians

Purpose Police officers often write reports about witnessed incidents, which may serve as evidence in court. We examined whether incident reports and identifications by police officers, and in particular specialized detectives on surveillance teams, are more complete or more accurate than reports and identifications by civilian observers. Methods Our sample included 46 civilians, 52 uniformed police officers, and 42 surveillance detectives. Participants viewed a 15-min video of a drug transaction and were allowed to take notes while watching. Before viewing the video, all participants received a priority list of information considered most relevant to the police investigation, which had been constructed by an expert panel. Subsequently, participants completed a questionnaire addressing different types of crime-relevant information in the incident. They also viewed target-present and target-absent lineups: Two for persons central to the drug transaction and one for a background detail. Results Reports of uniformed police officers and detectives on surveillance teams were significantly more complete than reports of civilians, particularly for the top-three priorities of crime-relevant information. Moreover, reports by detectives were significantly more accurate than reports by uniformed police officers and civilians. Detectives were also significantly more likely to identify the persons from the lineup, whereas civilians were significantly more likely to identify the background detail. Conclusions Our findings demonstrate that police officers, and in particular specialized detectives on surveillance teams, are more observant of the crime-relevant aspects of an incident than civilian observers. Theoretical and practical implications are discussed.

The provenance of émigrés: the validity of measuring knowledge of places

ABSTRACT Establishing the origin of those seeking asylum is essential but difficult as asylum seekers often cannot corroborate their origin claim with documents. The aim of the present study was to assess whether asking knowledge questions, sketch questions and impossible questions are valid methods to determine the veracity of an origin claim. Participants (N = 105) from Tilburg (truth-tellers), Maastricht (partial liars) and Gothenburg (full liars) were asked to convince an interviewer that they originated from Tilburg. Half of them prepared and half of them did not prepare themselves for the interview. They were asked 10 knowledge questions typically asked to assess the credibility of origin claims, 4 impossible questions and 1 sketch question. Participants from Tilburg answered more questions correctly than participants from Maastricht and Gothenburg. Performance also improved with preparation. Even though the results did provide some support for the validity of assessing claims about origin by asking knowledge questions, the differences between the groups were modest, and it was impossible to correctly identify all truth-tellers and liars. Changing the output modality from verbal answering to sketching contributed to the credibility assessment of origin claims, whereas impossible questions were not discriminatory.

The Forensic Confirmation Bias: A Comparison Between Experts and Novices

A large body of research has described the influence of context information on forensic decision‐making. In this study, we examined the effect of context information on the search for and selection of traces by students (N = 36) and crime scene investigators (N = 58). Participants investigated an ambiguous mock crime scene and received prior information indicating suicide, a violent death or no information. Participants described their impression of the scene and wrote down which traces they wanted to secure. Results showed that context information impacted first impression of the scene and crime scene behavior, namely number of traces secured. Participants in the murder condition secured most traces. Furthermore, the students secured more crime‐related traces. Students were more confident in their first impression. This study does not indicate that experts outperform novices. We therefore argue for proper training on cognitive processes as an integral part of all forensic education.