“The weakest ink is stronger than the sharpest memoryâ€: testing the effects of witness note taking and retention interval on eyewitness memory

Objectives: The subject of eyewitness memory has been in the mainstream of empirical and theoretical activities in the discipline of forensic psychology with scholars devoting their time on devising a technique, tool, or approach for improving eyewitness memory. The present study examines the effects of note taking and retention interval on eyewitness memory. Design: A 2 (witness note: note v no note) x 2 (retention interval: two days v one week) between group MANOVA factorial design was used in this study. The dependent variables are (a) eyewitness memory (verbal recall) measured in three categories: (i) correct (ii) incorrect (error) and (iii) confabulations and; (b) identification accuracy.Methods: 40 students from various undergraduate disciplines volunteered to participate in the study. A three minute film depicting a bank robbery was shown to the participants. After watching the film, their memories for the event were tested in terms of verbal recall and identification of the perpetrator from the lineup. Results: Using 2x2 MANOVA, the result shows that there is a multivariate difference between note and no note on the combined DVs, F (3, 34) =3.61; p=.023; Wilk’s Lamda=0.76; partial eta squared=0.24 with correct recall accounting for the significant difference, F (1,36) =10.62; p=.002; partial eta squared =0.23. There was no multivariate difference between two days and one week interval group on the combined DVs, F (3,34) =0.67; p=0.58; Wilk’s Lambda=0.94; partial eta squared=0.056. Furthermore, there was no significant interaction between witness note taking and retention interval on the combined DVs, F (3, 34) =0.29; p=0.84; Wilk’s Lambda=0.98; partial eta squared=0.025. The effects of note taking and retention interval on identification accuracy were also examined. The result of a 2x2 chisquare test showed no evidence of association between these two variables and identification accuracy. For participants instructed to re-read their notes, there was no correlation between reviewing own note and correct recall. Conclusion: The results of the present study have shown that regardless of time interval, note taking can serve as a memory aid to eyewitness (es) of crime events. Note taking increases recall of correct information. However, it does not lead to increase in correct identification.</p

Independent effects of resolution and set size on recognition memory for unfamiliar faces

Visual working memory (VWM) is a limited-capacity resource for the temporary storage of visual information (Cowan, 2001). Selective visual attention can protect VWM capacity by filtering relevant from irrelevant information during encoding or maintenance (Griffin & Nobre, 2003). The current study was designed to investigate the consequences of attentional selection on the accuracy of recognition for unfamiliar faces. We used a Change Detection task to measure d’ for cued and uncued faces in displays of 1, 2 and 4 faces, in a free-view (Experiment 1) and single-fixation Experiment 2) displays. In both experiments, recall accuracy was greater for cued than uncued faces. Recognition accuracy was also higher in free-view compared to single fixation displays and declined as a function of set size.This suggests the acquisition of high spatial frequency information during saccadic sampling improves recognition memory. Importantly, this advantage appears to be independent of the decrease in accuracy associated with set size, indicating that increasing the resolution of memoranda in VWM does not dilute resources in the same way as increasing the number of objects to remember.</p

Target distinctiveness modulates resource allocation in visual working memory for faces: implications for eyewitness face identification

Visual working memory (VWM) is a limited-capacity resource for the temporary storage of visual information (Cowan, 2001). Selective visual attention can protect VWM capacity by filtering relevant from irrelevant information during encoding or maintenance (Griffin & Nobre, 2003).The aim of the current study was to investigate whether target distinctiveness bias the allocation of visual working memory (VWM) resources during the encoding of unfamiliar faces. The results indicate that VWM capacity for unfamiliar faces is poor and declines as a function of the number of faces in the display (load). When one of the faces in the display was made distinct (i.e. by adding a tattoo to it), recall accuracy was independent of load, suggesting bottom-up attentional mechanisms protect against competition for limited VWM resources. These findings have a number of implications in real-world eyewitness scenarios. For example, the accuracy of eyewitness identification is likely to depend upon the number of individuals at the crime scene and differences in their salient visual characteristics.</p

Spatial attention can bias the accuracy of eyewitness identification

Visual working memory (VWM) is a limited-capacity resource for the temporary storage of visual information (Cowan, 2001). Selective visual attention can protect VWM capacity by filtering relevant from irrelevant information during encoding or maintenance (Griffin & Nobre, 2003).The aim of the current study was to investigate changes in the accuracy of face recognition memory when attention was reflexively oriented to the location of a face before (pre-cue) or after (retro-cue) it was disappeared. The results indicate that VWM capacity for unfamiliar faces is poor and declines as a function of the number of faces in the display (load). When attention was oriented by a pre-cue, recall accuracy was independent of load, suggesting attention captures VWM resource in a reflexive manner. This advantage was not observed for retro-cued faces, suggesting reflexive attention operates by biasing VWM resources during encoding rather than the maintenance of remembered faces. These findings have a number of implications in real-world eyewitness scenarios. For example, the accuracy of eyewitness identification is likely to depend upon the number of individuals at the crime scene and differences in their salient visual characteristics.</p