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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Electrophysiological correlates of correct and incorrect eyewitness identification: the role of the N250 and P300 in real-world face recognition.

Friesen, Krista B. 27 January 2011 (has links)
This set of studies used event-related potentials (ERPs) to investigate the electrophysiology of face recognition as it may occur in real-life circumstances including eyewitness identification. Research using photographs has identified two ERP components as being associated with memory function, the N250 (an early indicator of perceptual recognition) and the P300 (associated with stimulus evaluation, task-relevance, and probability), however, there is no published research examining the relationship between these components and memory for live events, and recognizing a face seen briefly in real-life is somewhat different than recognizing a face only seen in a photograph. The present set of three studies employed a “target / non-target” paradigm that used a live interaction at each encoding stage. In Experiment 1, participants were introduced to and asked to identify their study experimenter as the target. In the second experiment, participants were introduced to the same experimenter and asked to imagine that they witnessed her committing a convenience-store robbery. Participants were asked to “cover” for the experimenter by choosing a different photo from the line-up to accuse as the culprit – they are asked to lie. In Experiment 3, participants witnessed a live simulated theft and were asked to identify the culprit from a line-up. In all three experiments the line-up paradigm was identical – participants were shown a repeated series of sequentially-presented photographs and were asked to correctly identify one target among nine foils (non-targets), while brainwaves were recorded. Results showed that across all three studies, both the N250 and P300 were attenuated for the person selected as the target, in comparison to correct rejections of foils. Additional results from Experiment 2 showed that, compared to rejections of foils, both the N250 and P300 were enhanced for rejections of the experimenter-photo when participants were “covering” for her. In Experiment 3, participants who were unable to correctly identify the culprit showed that the N250 to incorrect rejections of the culprit was larger than correct rejections of foils. Finally, a comparison of participants who correctly identified the culprit and those who incorrectly identified a foil showed that the amplitude of the N250 and P300 to the selected culprit were equivalent regardless of eyewitness accuracy. Collectively, results from Experiments 1, 2 and 3 provide support that the memory effects indicated by the N250 and P300 components reported in laboratory studies generalize to person memories acquired during live interactions.
72

Eyewitness testimonies : The memory and meta-memory effects of retellings and discussions with non-witnesses

Sarwar, Farhan January 2011 (has links)
This thesis investigated the effects of eyewitnesses retellings and discussions with non-witnesses on the eyewitness memory and meta-memory judgments. In Study I, the effect of eyewitness discussions with non-witnesses (persons who had not experienced the event) on eyewitness memory and meta-memory realism for the overall information about an event was investigated. The results suggest that discussions of an experienced event may reduce some of the beneficial memory and meta-memory effects caused by mere retellings, but may not have great negative effects compared to a control condition. Analysis of the type of questions asked suggests listeners ask more about the peripheral details as compared with the central details. In a follow-up study to study I conducted a year later participants in the Retell condition no longer showed evidence of the memory and meta-memory benefits evident at the original final test after about 24 days. However, participants in the Retell condition recalled a higher number of correct items than participants in the Control condition. In Study II, the effect of eyewitness discussions with non-witnesses on eyewitness memory and meta-memory realism for different types of information was investigated. The different types of information were Forensically central, Forensically peripheral, and Non-forensic information. These are types of information that the police may ask at the beginning of a crime investigation. The results from the two experiments showed that participants had better memory and meta-memory realism for Forensically central and Non-forensic information than for Forensically peripheral information. Moreover, participants in the four conditions were equally capable of distinguishing between correct and incorrect items. Further, in Experiment 1 participants in conditions involving retelling and discussing the event reported more total number and number of correct Forensically central items as compared to the Control condition. Study III investigated if retellings and discussions would cause more reminiscence and hypermnesia than mere retellings. The results showed that discussions indeed cause more reminiscence and hypermnesia over the five sessions as compared to mere retellings. The results also showed that the number of times a piece of in- formation was repeated over the sessions was associated with a higher probability for that piece of information being retrieved at the final recall. Interestingly, if the information was retold or discussed in an earlier or later session did not predict if this information would be reported in the testing session or not. Last, the results showed that the forensically peripheral information, but not forensically central information was affected by the reiteration effect (i.e., the effect that confidence tends to increase when a person asserts the same statement many times). This may be due to the fact that the peripheral information was less integrated than the central information. / Det är vanligt att ögonvittnen återger och diskuterar en upplevd brottshändelse med sin familj och vänner. Syftet med dessa diskussioner är att uppdatera familj och vänner om vad som är nytt. Dessa diskussioner har konsekvenser för ögonvittnets senare minnesrapportering och meta-minnesbedömningar. Med minnesrapportering menas här vad ett ögonvittne kan återerinra sig om den bevittnade händelsen och med meta-minnesbedömningar menas ögonvittnets känslor av säkerhet på att hans/hennes minnen av händelsen är korrekta. Vittnens meta-minnesbedömningar kallas nedan konfidensbedömningar. Med uttrycket ”god realism” i meta-minnesbedömningarna menas att nivån på vittnets konfidensbedömningar matchar nivån på korrektheten i vittnets minnesrapportering av den upplevda händelsen. Vittnets minnesrapportering och konfidensbedömningar av sina rapporterade minnen är viktig information i kriminaltekniska sammanhang. Minnet hjälper oss att förstå detaljerna i brottshändelsen och vittnets konfidensbedömningar ger hjälp att förstå korrektheten av dessa minnen. Denna avhandling har undersökt effekterna av att ögonvittnen återberättar och diskuterar (en filminspelning av) en upplevd brottshändelse med icke-vittnen (personer som inte upplevt händelsen) på ögonvittnens minnesrapportering och på deras konfidensbedömningar av de rapporterade minnena. I Studie I fick deltagarna först se en kort film (c:a 4 minuter) och därefter fem gånger över en tre-veckorsperiod uppdelade i tre betingelser antingen enbart fick återberätta händelsen eller både återberätta och diskutera händelsen med icke-vittnen (antingen i en laboratoriemiljö eller med familjemedlemmar och vänner). Lyssnarna var nya personer i var och en av de fem sessionerna. Dessa tre försöksbetingelser jämfördes mot en kontrollbetingelse där dessa aktiviteter inte skedde. Alla deltagarna genomförde en avslutande sjätte testsession där vittnena fick instruktionen att återberätta allt vad de kan minnas av den upplevda händelsen (dvs öppen fri framtagning) och tre dagar senare ge konfidensbedömningar av de olika ingående elementära minneutsagorna i de rapporterade minnena. Av intresse i studien var alltså effekten av upprepat återberättande och diskussioner av en upplevd händelse på ögonvittnens minnesrapportering och på realismen i vittnenas konfidensbedömningar i den avslutande sjätte testsessionen. Resultaten tyder på att diskussioner om en upplevd händelse kan minska några av de positiva effekterna på kvalitén i minnesrapporteringen och på realismen i meta-minne som orsakas av enbart återberättande, men att diskussionerna inte får stora negativa effekter jämfört med en kontrollbetingelse där återberättande och diskussioner av händelsen inte skett. Analys av vilken typ av frågor lyssnarna ställde visade att man frågade mer om de perifera detaljerna i händelsen, jämfört med händelsens centrala detaljer (i första hand handlingar). En uppföljande studie till studie I genomfördes ett år senare. Denna studie visade inga kvarstående tecken på de fördelar på minnesrapportering och meta-minne som deltagarna i den betingelse som enbart återberättat händelsen fem gånger uppvisade i slutsessionen i Studie I efter c:a 24 dagar. Däremot hade deltagarna, i den betingelse som enbart återberättat händelsen, efter ett år ett högre antal korrekta minnesrapporterade utsagor jämfört med deltagarna i kontrollbetingelsen. Studie II utgick delvis från samma data som i Studie I. Här undersöktes effekten av ögonvittnens diskussioner med icke-vittnen på ögonvittnens minne och meta-minne realism för olika typer av information. De olika typer av information som analyserades var Forensiskt central, Forensiskt perifer och Icke-forensiskt relevant information. De två Forensiskt relevanta informationstyperna är sådan information som det är troligt att polisen kan vilja ha i början av en brottsutredning. Resultaten från de två experimenten i Studie II visade att deltagarna hade bättre minne och meta-minne realism för Forensiskt central och för Icke-forensiskt relevant information än för Forensiskt perifer information. Dessutom var deltagarna i de fyra betingelserna i Experiment I (samma fyra betingelser som i Studie I) lika kapabla att skilja mellan korrekt och inkorrekt objekt med hjälp av nivån på sina konfidensbedömningar för alla tre informationstyperna. Experiment 1 i Studie II visade också att deltagarna i de betingelser där deltagarna återberättade och diskuterade händelsen rapporterade ett högre antal korrekta Forensiskt centrala minnesutsagor jämfört med kontrollbetingelsen. Studie III gällde data från två av betingelserna i Studie I, närmare bestämt inspelade data från de fem återgivningsomgångarna i den betingelse där deltagarna enbart återberättat händelsen och inspelade data från den betingelse där deltagarna både återberättade och diskuterade händelsen i laboratoriet. Studien visade att deltagarna i den betingelse där deltagarna både återgav och diskuterade händelsen uppvisade mer reminiscens (fler minnesutsagor, både korrekta och inkorrekta över de fem sessionerna) och mer hypermnesi (tillskott av mer korrekta minnesutsagor över de fem sessionerna) än deltagarna i den betingelse där de bara återberättade händelsen fem gånger över tre veckor. Resultaten visade också att antalet gånger en minnesutsaga upprepades under sessionerna var förenat med en högre sannolikhet för att minnesutsagan skulle återges vid den slutliga återgivningen. Däremot hade det, intressant nog, ingen effekt om minnesutsagorna hade återberättats eller diskuterats i en tidigare eller senare session (av de 5 sessionerna) på om minnesutsagan skulle redovisas i den sjätte testsession eller inte. Slutligen visade resultatet i Studie III att de Forensiskt perifera minnesutsagorna, men inte de Forensiskt centrala utsagorna, uppvisade en så kallad reitereringseffekt vilken innebär att säkerhetskänslan (dvs upplevd konfidens att utsagan är korrekt) höjs som en effekt av att utsagan upprepas fler gånger. Detta kan bero på att den Forensiskt perifera informationen är mindre välintegrerad än den Forensiskt centrala informationen.
73

Witnesses with developmental disabilities and the cognitive interview : the effects of time delay on recall and suspect identification /

Isaacs, Barry J. January 2004 (has links)
Thesis (Ph.D.)--York University, 2004. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 73-82). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99188
74

Investigating investigators: Examining the impact of eyewitness identification evidence on student-investigators

Boyce, Melissa 21 April 2008 (has links)
This research examined the impact of eyewitness identification decisions on student-investigators. Undergraduates played the role of police investigators and interviewed student-witnesses who in Studies 1 and 2 had been shown either a good or poor view of the perpetrator or in Study 3 viewed either a Caucasian or an Asian criminal, in a video-taped crime. Based on information obtained from the witness, student-investigators then chose a suspect from a database containing information about potential suspects and rated the probability that their suspect was the culprit. Investigators then administered a photo lineup to witnesses, and re-rated the probability that their suspect was guilty. Student-investigators were highly influenced by eyewitness identification decisions, typically overestimating the information gained from the identification decision (except under conditions that led witnesses to be very accurate), and generally did not differentiate between accurate and inaccurate witnesses.
75

Investigating investigators : how presentation order influences investigators’ interpretations of alibi and bystander witness evidence

Dahl, Leora Catherine 05 June 2008 (has links)
Eyewitness identification evidence is often essential in criminal investigations, yet little is known about how police investigators evaluate identification evidence. This research simulated a police investigation by having participant-investigators obtain information about a crime, examine a database of potential suspects with the goal of choosing a likely suspect for the crime, and evaluate an eyewitness's lineup identification decision. Experiments 1 and 2 examined the effect of order of presentation of the eyewitness decision. When the eyewitness identified the investigator's suspect, ratings of the suspect's guilt were similar regardless of when the eyewitness decision occurred. However, when the witness reported that the culprit was not present in the lineup, a recency effect occurred (the information that was presented last had a larger impact). Experiment 3 continued to examine order effects while also examining how investigators evaluated alibi information and eyewitness testimony when they had already identified a suspect in the case. The investigators evaluated alibi evidence that was either strong or weak (in regards to exonerating the suspect) and eyewitness evidence involving a witness who either identified the investigator's suspect or rejected the suspect (by not making an identification). The order of presentation of the alibi information and eyewitness testimony was manipulated such that half of the participants received the alibi information before the eyewitness testimony while the other half received the alibi information after the eyewitness testimony. Both the eyewitness decision and alibi evidence affected ratings of guilt. A recency effect was present only in the ID Suspect/Strong alibi conditions, such that when investigators saw the witness identify the suspect and then received the strong alibi, they rated the likelihood that their suspect had committed the crime as lower than when they received the strong alibi first and then saw the witness identification. Otherwise, the two forms of evidence had an additive effect. Together, these studies provide a valuable examination of the influence of presentation order and the importance of different forms of evidence on role-playing police investigators.
76

Attentional Competition: Weapon Focus, Encoding Time, and Memory Accuracy Correlations between Crime Scene Items

Kekessie, Seyram 27 April 2015 (has links)
The present study examines the relationships between recognition and recall accuracy of faces, and recognition and recall accuracy of objects. Secondly, this study examines the influence of weapon presence on description and identification accuracy, and whether encoding time moderates the effect. 713 participants watched an image that was either displayed for five seconds or twenty seconds, and either included a weapon or no weapon. Subsequently, they were asked to give descriptions of what they saw before viewing a lineup that either included the perpetrator or was made up of innocent suspects. Results indicated that witnesses’ description accuracy of the crime scene had little or no predictive abilities with regards to their facial identification accuracy. Secondly, there was a weapon focus effect found for faces but not for objects. Furthermore, this effect was eliminated at long encoding times. Finally, increasing encoding time improved recognition of objects, but not faces. Results suggest that prior inaccuracy on one aspect of testimony is not necessarily indicative of subsequent inaccuracy on another aspect of testimony. This finding has implications for how jurors and judges should evaluate witness testimony when assessing credibility in the courtroom.
77

Eyewitness Choosing Behavior: The Role of Ecphoric Experience and Non-Memorial Cues

Cahill, Brian S 13 November 2015 (has links)
Researchers’ attempts at understanding the processes underlying witness choosing behavior have focused on applying models that predict that identifications will be primarily driven by memorial factors. However, research has shown that several non-memorial variables affect witness choosing behavior (e.g., administrator influence, clothing bias, co-witness information); thus a full understanding of the processes underlying witness choosing behavior needs to account for these effects. While the memory-based models do attempt to provide explanations for the effects of non-memorial based variables on choosing behavior they all do so within a memorial context. However, I will argue a lineup task is not simply a memory task but a task that allows both memorial and non-memorial variables to impact choosing behavior, with the latter affecting choosing through an inferential process. The purpose of the present study was to provide an initial test of a novel, inferential based framework (i.e., the Competition/Corroboration Conceptualization). In short, this framework predicts that the effect of non-memorial cues on choosing behavior will occur via leading witnesses to deliberatively infer who the suspect is, and that the extent to which a deliberative process is engaged is dependent upon the witnesses’ ecphoric experience. Study 1 (N = 146) had mock-witnesses view several lineups with non-memorial cues embedded in them; results showed that mock-witnesses engaged in an inferential process by using the cues in the lineup to help guide their choosing behavior. Study 2 (N = 376) had witnesses view either a target-present or target-absent lineup where a non-memorial cue suggested that witnesses should either identify the target, identify a specific filler, or was not included. Witnesses then made an identification decision. Results from study 2 showed that the presence of a non-memorial cue suggesting the suspect’s guilt increased suspect identifications compared to its absence, and importantly, that this effect was greater for witnesses who had a weak ecphoric experience. Findings across both studies suggest that an inferential based framework of witness choosing more fully encompasses the underlying nature of witnesses’ phenomenological experience. Practical implications and future directions are discussed.
78

Two approaches to assessing eyewitness accuracy

Baldassari, Mario J. 21 December 2017 (has links)
This dissertation presents two individual-difference measures that could be used to assess the validity of eyewitness identification decisions. We designed a non-forced two-alternative face recognition task (consisting of mini-lineup test pairs, half of which included a studied face and half of which did not). In three studies involving a total of 583 subjects, proclivity to choose on pairs with two unstudied faces weakly predicted mistaken identifications on culprit-absent lineups, with varying correlation coefficients that failed to reach the value r = 0.4 found in Baldassari, Kantner, and Lindsay (under review). The likelihood of choosing correctly on pairs that included a studied face was only weakly predictive of correct identifications in culprit-present lineups (mean r of .2). We discuss ways of improving standardized measures of both proclivity to choose and likelihood to be correct when choosing. The second measure is based on the Guilty Knowledge Test (GKT), a lie detection method that utilizes an oddball paradigm to evoke the P300 component when a witness sees the culprit. This GKT-based lineup was intended to postdict identification accuracy regardless of witnesses’ overt responses, thus faces are used as stimuli. Half of participants were instructed to respond as if they knew the culprit and wanted to falsely exonerate him. P300 amplitudes evoked by the culprit were indistinguishable from those evoked by a different learned face but were larger than P3s evoked by unfamiliar faces in both the described lying condition and the group of participants who intentionally told the truth. / Graduate / 2018-12-05
79

Kognitivní interview jako prostředek podpory přípravného řízení / Cognitive interview as a supportive method in criminal investigation

Gábrišová, Julie January 2021 (has links)
The presented diploma thesis presents the method of cognitive interview and describes the possibilities of its use in the preparatory proceedings. The theoretical part defines the interrogation of a witness in the preparatory proceedings and introduces the psychological processes in creating witness statement. In the following chapters, the thesis focuses only on the method of cognitive interview, presents its processs, basic techniqes, but also a comparison with other interrogation methods. The greatest emphasis of the thesis is on the use of cognitive interview with the police and specific groups that participate in the preparatory proceedings. Part of the thesis is also research, which is divided into two parts. Each of them aims to describe the current process of interrogating witnesses and victims in the Czech Republic, to help answer the question of whether it is important to try to implement the method of cognitive interview in the Czech environment. Thanks to the analysis of five interrogation videos and seven interviews with police officers from practice, it was possible to identify some interrogation techniques that are considered effective in the cognitive interview method, but also those that the method recommends not to use. Of the four cognitive interview techniques, which are...
80

Kognitivní interview jako prostředek podpory přípravného řízení / Cognitive interview as a supportive method in criminal investigation

Gábrišová, Julie January 2021 (has links)
The presented diploma thesis presents the method of cognitive interview and describes the possibilities of its use in the preparatory proceedings. The theoretical part defines the interrogation of a witness in the preparatory proceedings and introduces the psychological processes in creating witness statement. In the following chapters, the thesis focuses only on the method of cognitive interview, presents its processs, basic techniqes, but also a comparison with other interrogation methods. The greatest emphasis of the thesis is on the use of cognitive interview with the police and specific groups that participate in the preparatory proceedings. Part of the thesis is also research, which is divided into two parts. Each of them aims to describe the current process of interrogating witnesses and victims in the Czech Republic, to help answer the question of whether it is important to try to implement the method of cognitive interview in the Czech environment. Thanks to the analysis of five interrogation videos and seven interviews with police officers from practice, it was possible to identify some interrogation techniques that are considered effective in the cognitive interview method, but also those that the method recommends not to use. Of the four cognitive interview techniques, which are...

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