The effects of immediate recall on eyewitness accuracy and susceptibility to misinformation

Eyewitnesses can be influenced by misinformation that they encounter when discussing the event with a co-witness. Some studies have found that an immediate recall of the event can inoculate eyewitnesses against such misinformation; others have found that it increases susceptibility to misinformation. These different findings may be due to methodological factors, so the aim of this study was to investigate the effects of three different recall conditions. An immediate cued recall, free recall or no recall was given to 88 participants after they watched a crime video. They then discussed the video with a confederate who introduced correct and incorrect information about the video. Accuracy and amount of recall was tested one week later. It was found that the immediate-recall questionnaire did not make participants more susceptible to misinformation in comparison to no-recall participants, indeed the data trended the other way, suggesting that immediate-recall inoculated participants against misinformation. Furthermore, the provision of correct post-event information increased memory accuracy, especially after immediate recall.     

Minimizing culpability increases commission errors in a mock crime paradigm

Purpose. Empirical studies have demonstrated that feigning amnesia undermines memory for a mock crime. Not much is known about the effects of other culpability‐reducing strategies on memory. The present study investigated what strategies participants use when they are instructed to minimize culpability and if these strategies undermine memory to a similar extent as claiming amnesia. Methods. Participants performed a mock crime. Next, they were either instructed to minimize culpability for this mock crime in a simulated interrogation or asked to respond honestly. One week later, memory for the mock crime was tested. Results. None of the participants claimed amnesia when trying to minimize culpability. Conversely, all participants fabricated an alternative account of their role in the crime. Compared with responding honestly on both tests, fabricating an alternative story on the first test undermined memory for the mock crime in terms of commission errors. Correct recall was unaffected. It appeared that this effect was related to story length: the longer the fabricated story, the more the commission errors when telling the truth 1 week later. Conclusions. Fabricating an alternative story (i.e. lying) did not compromise correct recall, but induced more commission errors. The findings are discussed in terms of possible underlying mechanisms.     

Providing eyewitnesses with initial retrieval support: what works at immediate and subsequent recall?

The effect of retrieval support on eyewitness recall was investigated in two experiments. Based on the outshining hypothesis, Experiment 1 tested whether retrieval support enhances witness performance (compared to free recall) especially when witnessing conditions are suboptimal (e.g., because witnesses were distracted during the crime). Eighty-eight participants watched a videotaped crime with either full or divided attention and subsequently received retrieval support with the Self-Administered Interview© (SAI) or completed a free recall (FR). One week later (Time 2 – T2) all participants completed a second FR. Unexpectedly, retrieval support did not lead to better memory performance than FR under divided attention conditions, suggesting that retrieval support is not effective to overcome adverse effects of divided attention. Moreover, presence of retrieval support at Time 1 (T1) had no effect on memory performance at T2. Experiment 2 (N = 81) tested the hypothesis that these T2-results were due to a reporting issue undermining the memory-preserving effect of T1-retrieval support by manipulating retrieval support (SAI vs. FR) at T1 and T2. As expected, T1-retrieval support led to increased accuracy at T2. Thus, the beneficial value of T1-retrieval support seems greatest with high-quality T2-interviews. Interviewers should consider this when planning a subsequent interview.     

Simulating amnesia and memories of a mock crime

Abstract

Defendants often feign (i.e. simulate) dissociative amnesia for their crimes. The Symptom Validity Test (SVT) may be used to detect such feigning. Some studies have shown that feigning amnesia for a mock crime has memory-undermining effects. In this study, we wanted to replicate the memory-undermining effects of simulated amnesia. We also examined whether such effects would occur when participants’ memories were evaluated with a SVT. Thirty participants committed a mock crime and then simulated amnesia for it. During a follow-up test, participants were instructed to perform as well as they could on a free recall test and a SVT. Their memory performance was compared with that of a control group (n=30). Although only a minority of simulating participants (7%) was detected by our SVT, the memory-undermining effect of simulating amnesia appeared to be a robust phenomenon. That is, ex-simulators displayed poorer free recall, more commission errors, and lower SVT scores relative to memory performance of honestly responding controls. However, at follow-up testing the poor memory of ex-simulators did not take the form of a real amnesia (i.e. random performance on SVT).     

Bolt Cutter Blade's Imprint in Toolmarks Examination

Bolt cutters are known as cutting tools which are used for cutting hard objects and materials, such as padlocks and bars. Bolt cutter blades leave their imprint on the cut objects. When receiving a cut object from a crime scene, forensic toolmarks examiners can determine whether the suspected cutting tool was used in a specific crime or not based on class characteristic marks and individual marks that the bolt cutter blades leave on the cut object. The paper presents preliminary results of a study on ten bolt cutters and suggests a quick preliminary examination—the comparison between the blade thickness and the width of the imprint left by the tool on the cut object. Based on the comparison result, if there is not a match, the examiner can eliminate the feasibility of the use of the suspected cutting tool in a specific crime. This examination simplifies and accelerates the comparison procedure.     

人体气味的证据价值及检验技术进展

人体气味是具体人的一种生物信息,皮肤腺是人体气味产生之源。由遗传基因控制的人类白细胞抗原,经由免疫系统决定人体气味的特征。遗留于犯罪现场的人体气味具有相对稳定性,是与案件事实相关联的一种物证,具有一定的证据能力。警犬鉴别是辨识人体气味的主要技术手段。电子鼻、气相色谱质谱等化学分析仪器也可用于人体气味的检测分析。利用气相色谱质谱(GC/MS)对气味进行辨识具有嗅觉学的作用。警犬鉴别人体气味的结果与仪器分析的结果相互印证是检测分析人体气味证据技术的发展方向,也是人体气味证据走上法庭的关键技术。     

犯罪现场层次论

犯罪现场层次是犯罪现场存在表现及其被侦查人员认知的程度。犯罪现场是由犯罪时间、犯罪空间、犯罪嫌疑人条件、犯罪痕迹物证、犯罪活动过程、犯罪心理、犯罪证据等各种层次构成的复合体。研究犯罪现场层次论也是研究犯罪现场构成要素的存在及其在不同层面的联系。犯罪现场层次也是研究和揭示犯罪现场存在的一种认知。研究犯罪现场层次问题,也可以使我们对犯罪现场状况及其勘查工作质量给以程度判定。     

Eyewitness Memory for Firearms: Narrative Accounts and Specific Questioning in the Elucidation of Accurate Information

Much eyewitness research has addressed memory for persons and scenes, but limited work has addressed memory for firearms, frequently an important point in investigations and in court. The present research addressed this topic using the format of a traditional police interview, in which seventy subjects provided unrestricted free recall of a weapon seen in a crime situation, followed by responses to specific questions. Three firearms were used in a between-subjects format: a typical modern semi-automatic pistol, a less-typical Old West revolver, and an atypical single-shot muzzle-loading pistol. In the free recall stage, respondents provided about four times as many correct as incorrect details. However, in the specific-question stage, there were only 1.2 times as many new correct responses as new incorrect details, consistent with current cognitive theory. No difference between the weapons was observed in the production of correct responses, but the revolver and single-shot pistol resulted in more incorrect responses than did the modern semi-automatic, regardless of the saliency of weapon features. These results demonstrate the importance of the original, initial free recall phase in developing accurate identification of a given weapon, and of the type of weapon involved, and have important implications for police interviewing for accurate weapon identification.     

Nature and place of crime scene management within forensic sciences

This short paper presents the preliminary results of a recent study aimed at appreciating the relevant parameters required to qualify forensic science as a science through an epistemological analysis. The reader is invited to reflect upon references within a historical and logical framework which assert that forensic science is based upon two fundamental principles (those of Locard and Kirk). The basis of the assertion that forensic science is indeed a science should be appreciated not only on one epistemological criteria (as Popper's falsification raised by the Daubert hearing was), but also on the logical frameworks used by the individuals involved (investigator, expert witness and trier of fact) from the crime scene examination to the final interpretation of the evidence. Hence, it can be argued that the management of the crime scene should be integrated into the scientific way of thinking rather than remain as a technical discipline as recently suggested by Harrison.     

Eyewitness Memory in Context: Toward a Taxonomy of Eyewitness Error

Although eyewitness memory and identification have captured substantial research interest in the past decades, an understanding of the types and prevalence of errors typically made by eyewitnesses is lacking. The purpose of the present research was to begin the development of a taxonomy of eyewitness error, employing standardized stimuli and established techniques. Respondents were exposed to a crime scene modeled on SWAT-training scenarios for systematically varied exposure times, and were then asked to describe what they had seen. The stimuli and questions employed were prepared with the aid of senior police field training officers. As anticipated, eyewitness performance in general was subject to a variety of inaccuracies. Physical errors, such as mistakes in the clothing or physical characteristics of the perpetrator, or in details of the environmental context, predominated. However, other less-expected errors were also observed: in relatively low numbers of cases, witnesses inferred emotional states or intent on the part of the perpetrator or victim. Some contributed wholly artificial backstories, reported the future actions of the perpetrator or victim as memories, or even inserted themselves into the scene. The pattern of results was shown to interact with exposure time, gender of the perpetrator, and the presence or absence of weapons in the scene. The results of this study are consistent with reconfigurative theory dating to Bartlett (1932), with subsequent research, and with more recent work under the aegis of Gestalt/Feature-Intensive Processing theory. These findings provide information on types and prevalence of eyewitness error which should prove useful in investigative and courtroom settings.     

How to regulate forensic familial DNA searching in Hungary?

Forensic DNA analysis has the potential to provide useful information for criminal justice even in cases where there is no match, neither between the DNA profile generated from the crime scene and the existing DNA profiles in criminal databases, nor between the DNA collected at a crime scene and potential suspects. In contrast to traditional forensic genetic testing, forensic familial DNA searching does not provide evidence, but helps to generate investigative leads and narrow down the range of potential offenders. The aim of this study is to examine, whether there is a need for special regulation of this topic in Hungary.     

The persistence of memory: Forensic identification and extraction of cryptographic keys

The increasing popularity of cryptography poses a great challenge in the field of digital forensics. Digital evidence protected by strong encryption may be impossible to decrypt without the correct key. We propose novel methods for cryptographic key identification and present a new proof of concept tool named Interrogate that searches through volatile memory and recovers cryptographic keys used by the ciphers AES, Serpent and Twofish. By using the tool in a virtual digital crime scene, we simulate and examine the different states of systems where well known and popular cryptosystems are installed. Our experiments show that the chances of uncovering cryptographic keys are high when the digital crime scene are in certain well-defined states. Finally, we argue that the consequence of this and other recent results regarding memory acquisition require that the current practices of digital forensics should be guided towards a more forensically sound way of handling live analysis in a digital crime scene.     

Forensic Comparison of Soil Samples Using Nondestructive Elemental Analysis

Soil can play an important role in forensic cases in linking suspects or objects to a crime scene by comparing samples from the crime scene with samples derived from items. This study uses an adapted ED‐XRF analysis (sieving instead of grinding to prevent destruction of microfossils) to produce elemental composition data of 20 elements. Different data processing techniques and statistical distances were evaluated using data from 50 samples and the log‐LR cost (C_llr). The best performing combination, Canberra distance, relative data, and square root values, is used to construct a discriminative model. Examples of the spatial resolution of the method in crime scenes are shown for three locations, and sampling strategy is discussed. Twelve test cases were analyzed, and results showed that the method is applicable. The study shows how the combination of an analysis technique, a database, and a discriminative model can be used to compare multiple soil samples quickly.     

Inconsistencies across repeated eyewitness interviews: supportive negative feedback can make witnesses change their memory reports

Past work shows that direct negative feedback and suggestive questioning can lead eyewitnesses to change their memory reports. Applying Gudjonsson’s [2003. The psychology of interrogations and confessions: A handbook. West Sussex: Wiley] model of interrogative suggestibility to interviews with witnesses, the present two experiments examined how indirect negative feedback delivered in a supportive manner from an interviewer can make witnesses change what they report they remember experiencing. After viewing a video of a crime, participants were interviewed twice, with either supportive negative feedback (i.e. with the interviewer sympathetically suggesting why many people’s memory may be inaccurate) or neutral feedback between the two rounds of questions. Results showed that people given supportive negative feedback changed significantly more of their responses than those given neutral feedback. Lower confidence ratings were associated with greater response change, but overall, despite having changed more responses, people given supportive negative feedback did not have reduced confidence or perceived accuracy. Type of feedback did not impact accuracy, and accuracy was not systematically related to confidence or perceived accuracy. Given the role that eyewitness reports play in the criminal justice system, better understanding factors that impact consistency and reliability is vital.     

The Effects of Substance Use on Offender Crime Scene Behavior

Abstract:  Substance use has an effect on an individual's propensity to commit acquisitive crime with recent studies showing substance users more likely to leave forensic material at a crime scene. An examination of acquisitive crime solved in Northamptonshire, U.K., during 2006 enabled 70 crime scene behavior characteristics to be analyzed for substance and nonsubstance use offenders. Logistical regression analyses have identified statistically significant crime scene behavior predictors that were found to be either present at or absent from the crime scene when the offender was a substance user. Most significant predictors present were indicative of a lack of preparation by the offender, irrational behavior, and a desire to steal high value, easily disposed of, property. Most significant predictors absent from the crime scene were indicative of more planning, preparation, and execution by the offender. Consideration is given to how this crime scene behavior might be used by police investigators to identify offenders.     

Development of a Dundee Ground Truth imaging protocol for recording indoor crime scenes to facilitate virtual reality reconstruction

Early and accurate visualisation of a crime scene is highly desirable such that a rapid, agile, and informed decision-making process can be undertaken by an investigative team. We present a new standard operating procedure for imaging an indoor scene using DSLR cameras conventionally used by crime scene investigators and examiners. The standard operating procedure (SOP) enables the systematic photography of indoor spaces in such a way that the Structure from Motion (SfM) photogrammetry technique can be implemented, allowing the scene to be recreated in Virtual Reality (VR). To demonstrate the method’s validity, we compare two VR-rendered representations of an example scene using (a) photographs taken by an experienced crime scene examiner using a conventional photographic method and (b) photographs taken by a novice photographer following the developed SOP.     

Development of a fast, simple profiling method for sample screening using high resolution melting (HRM) of STRs

A screening assay has been developed to provide preliminary individualization of crime scene samples thus eliminating expensive, time-consuming short tandem repeat (STR) profiling of nonprobative samples. High resolution melting performed in a real-time PCR instrument is used to detect the slight melting differences between the length and sequence variations of 22 forensic STRs. Three STRs (vWA, D18S51, THO1) were chosen to develop an assay which was optimized for Mg++ concentration, annealing/extension time/temperature, assay volume, and bovine serum albumin addition. The assay was tested for reproducibility, uniformity for genotype, melting profile consistency, effects of inhibitors, and mixture effects. The assay could be used to determine DNA concentration when a standard curve is run simultaneously. Calculations of costs show that the assay can save significant time and money for a crime with many samples or suspects.     

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.     

The saliency of gestural misinformation in the perception of a violent crime

Recent research has revealed that misinformation from gestures can influence eyewitness memory. However, it is still unclear whether gestural misinformation can emulate the effects of verbal misinformation on the reporting of major details in serious crimes. To investigate the salience of suggestions provided nonverbally, and how these compare to those made verbally, two experiments were conducted. In Experiment 1, participants watched footage of a crime scene and were presented with one of two types of gestures during questioning that suggested different interpretations of the crime. The results confirmed that the gestures influenced responses, with participants altering their interpretation of the crime according to the information gestured to them. Experiment 2 built on this to investigate how comparable gestural influence was to verbal influence. The results revealed that gestural misinformation caused participants to alter their interpretation of the crime and elicited the same effects as verbal misinformation. Across the two experiments, participants were unlikely to identify the misleading gestures or report feeling misled by them. These results reveal new insights into the strength of gestural misinformation and show that, despite their subtle nature in communication, gestures can exert a powerful influence in eyewitness interviews.     

A Meta-Analytic Review of the Effects of High Stress on Eyewitness Memory

In the past 30 years researchers have examined the impact of heightened stress on the fidelity of eyewitness memory. Meta-analyses were conducted on 27 independent tests of the effects of heightened stress on eyewitness identification of the perpetrator or target person and separately on 36 tests of eyewitness recall of details associated with the crime. There was considerable support for the hypothesis that high levels of stress negatively impact both types of eyewitness memory. Meta-analytic Z-scores, whether unweighted or weighted by sample size, ranged from –5.40 to –6.44 (high stress condition–low stress condition). The overall effect sizes were –.31 for both proportion of correct identifications and accuracy of eyewitness recall. Effect sizes were notably larger for target-present than for target-absent lineups, for eyewitness identification studies than for face recognition studies and for eyewitness studies employing a staged crime than for eyewitness studies employing other means to induce stress.