The effects of local and global processing orientation on eyewitness identification performance

Recent work has demonstrated that performance on a simultaneous target-present photographic line-up can be enhanced by prior global processing orientation, and hindered by prior local processing orientation induced by processing Navon letter stimuli. A series of studies explore the generality of this processing bias effect using either videotaped scenarios or live interactions. Five experiments demonstrate that these effects are seen across a range of test stimuli, test formats, and test instructions. These data inform the processes engaged in by witnesses when making line-up identifications and indicate that it may be possible to improve the accuracy of witnesses making such judgements.     

The effects of training and transfer on global/local processing

We investigated interference, inhibition and transfer effects associated with training on a global-local task. Participants received 10,080 training trials on identifying local features of global/local stimuli. Global processing advantage was eliminated with practice. Global interference decreased with training whereas local interference developed with training. Transfer analyses indicated that training produced stimulus-specific effects in local processing and task-specific effects in global processing. Our findings are discussed in regards to models of global/local processing.     

The effects of local and global processing demands on perception and action

The line-bisection task, adapted to utilise a wooden rod as the bisection stimulus, has revealed that patients with visuo-spatial neglect may be more accurate at bisection when asked to pick up the rod, compared to pointing to its centre. We recently reported that neurologically intact participants show a similar dissociation on this task-demonstrating a rightward bias when pointing to the centre, which was not present when grasping the rod by the centre. The current paper examined how pointing and grasping responses were affected by adapted rod-bisection tasks that emphasised local or global processing. In Experiment 1, 26 participants completed four rod-bisection tasks. The rods were compound stimuli and the participants directed to focus on either the local or global level. The results demonstrated that when participants focused on the global level, the previous dissociations found for pointing and grasping conditions were evident. However, the perception of centre did change when participants focused on the local level: both the pointing and grasping responses were rightward biased. In Experiment 2, 42 participants completed three bisection tasks which again emphasised either the local or global level, but in different sets of stimuli. The results of this task further support the findings in Experiment 1: the rightward bias in the local-bisection task was again evident and in addition, the global-bisection task resulted in no bias and no difference between the pointing and grasping bisections. These results demonstrate how task demands can similarly affect the pointing and grasping responses, and indicate that local and global processing may be involved in perception/action dissociations on rod bisection.     

The effects of noise on the processing of global shape and local detail

Summary Two experiments investigated the effects of noise on the processing of global shape and local detail. Both experiments showed that noise improved ordered recall of local features but impaired recall of global shape, although the extent of the effect of noise was influenced by the size of the compound stimuli. Noise did not produce the same effects as those obtained when attention is manipulated by instructions, and it is possible that noise produced a change in the more passive aspect of attention rather than altering the active allocation of attentional resources.     

Postidentification feedback affects subsequent eyewitness identification performance

Eyewitnesses sometimes view more than one lineup during an investigation. We investigated the effects of postidentification feedback following one lineup on responses to a second lineup. Witnesses (N=621) viewed a mock crime and, later, attempted to identify the culprit from an initial (target-absent) lineup and a second (target-present or target-absent) lineup. Prior to viewing the second lineup, some witnesses received accurate feedback stating that the initial lineup did not contain the culprit. A compound-decision, signal detection approach allowed the effects of feedback on identification responses to be described in terms of differences in discriminability and response bias. For witnesses who made an incorrect foil identification from the initial lineup, feedback (vs. no feedback) was associated with poorer discriminability on the second test. For witnesses who correctly rejected the initial lineup, feedback (vs. no feedback) was associated with greater discriminability on the second test. Only witnesses who received feedback after an initial correct rejection performed at a level comparable with a single-lineup control group, suggesting that an initial identification test can impair, but not enhance, performance on a second test involving the same culprit. From a theoretical perspective, the results are consistent with the idea that the way people use memorial information when making memory decisions is flexible. Analyses of preidentification confidence ratings, obtained in a follow-up study (N=133), suggested that the effects of feedback on identification performance may have operated via differences in witnesses' metacognitive beliefs.     

Lineup administrator influences on eyewitness identification and eyewitness confidence

Lineup administrators were trained to respond to witnesses in such a way as to redirect them from making non-identifications or foil identification responses toward making identifications of the suspect. Compared to a no-influence control condition, suspect identification rates in the influence condition increased substantially and proportionally for guilty and innocent suspects. Administrators steered witnesses more specifically toward the suspect when the suspect was guilty than when the suspect was innocent. Post-identification confidence for correct identifications of the guilty suspect did not differ significantly across the influence and no-influence groups. However, post-identification confidence for false identifications of the innocent suspect was significantly lower for the influence group than for the no-influence group because witnesses who were influenced to make false identifications tended to be those who were less confident prior to the lineup, and also because those witnesses became less confident from pre- to post-identification.     

Implicit identification of irrelevant local objects interacts with global/local processing of hierarchical stimuli

This work aimed at studying interactions between automatic object identification and global/local perceptual processing. We designed a paradigm in which participants were presented with pairs of hierarchically organized items, composed of global forms made up of local forms. Both global and local forms could represent either objects or non-objects. Subjects were instructed to detect whether the two hierarchical items composing a pair were identical or different. In a dissimilar pair, items differed at one level (target level), the other level, made of similar forms on both sides, was irrelevant to perform the task. We hypothesized that the automatic identification of object could affect the global precedence principle defined by Navon. In agreement with our hypothesis, we found that when the irrelevant level was made of objects, the global precedence effect was reversed. In contrast, the irrelevant level had no effect when the target level included only objects, or when the irrelevant level was made of non-object, the global precedence principle was being preserved in these cases. This interaction is compatible with the existence of two distinct processes working in parallel, namely automatic identification and structural analysis, that could either interfere or act together for the detection of differences.     

Culture variation in the average identity extraction: The role of global vs. local processing orientation

ABSTRACT

Research has shown that observers often spontaneously extract a mean representation from multiple faces/objects in a scene even when this is not required by the task. This phenomenon, now known as ensemble coding, has so far mainly been based on data from Western populations. This study compared East Asian and Western participants in an implicit ensemble-coding task, where the explicit task was to judge whether a test face was present in a briefly exposed set of faces. Although both groups showed a tendency to mistake an average of the presented faces as target, thus confirming the universality of ensemble coding, East Asian participants displayed a higher averaging tendency relative to the Westerners. To further examine how a cultural default can be adapted to global or local processing demand, our second experiment tested the effects of priming global or local processing orientation on ensemble coding via a Navon task procedure. Results revealed a reduced tendency for ensemble coding following the priming of local processing orientation. Together, these results suggest that culture can influence the proneness to ensemble coding, and the default cultural mode is malleable to a temporary processing demand.     

The effects of post ‐identification feedback and age on retrospective eyewitness memory

Two studies examined the effects of post‐identification feedback, age, and retention interval on participants' memories and beliefs about memories for a videotaped event, as captured by a store surveillance camera. After viewing the video, they were then asked to identify the suspect from a target‐absent photo line‐up. After making their identification, some participants were given information suggesting that their identification was correct, while others were given no information about the accuracy of their identification. In both experiments participants who received confirming feedback indicated they were more confident in their identification, paid more attention to the video, and that they were more willing to testify in court than those who received no feedback. The confidence inflation effects of post‐identification feedback did not vary with retention interval or age. These results are consistent with a position focusing on accessibility, which suggests that witnesses have little or no retrievable recollection of how sure they were at the time of their identification. Copyright © 2005 John Wiley & Sons, Ltd.     

Positive and negative effects of physical context reinstatement on eyewitness recall and identification

The impact of context reinstatement (CR) on eyewitness recall and identification was explored in this study. Participants viewed a video of a staged theft and, following a 1‐week interval, were asked to identify the culprit and recall the event in either the same or in a different physical environment. Results suggested that CR enhanced the perceived familiarity of the lineup members, which in turn increased participants' willingness to identify someone in the lineup. Although CR significantly improved facial discrimination and identification accuracy when the target was present, it also increased confidence ratings beyond that warranted by the increase in accuracy. In terms of recall, reinstating the study context improved participants' free recall of both central and peripheral details and cued recall of peripheral details. The results were consistent with a (mis)attribution of familiarity and the outshining hypothesis. Copyright © 2009 John Wiley & Sons, Ltd.     

Hemispheric local/global processing revisited

Hemispheric differences for local and global processing were assessed with square and rectangular stimulus shapes which contained either squares or rectangles within them. Experiment 1 manipulated the overall size and area of the stimulus items, while experiment 2 kept stimulus area constant and manipulated the number of shapes inside the stimulus. In different conditions subjects judged whether the inside shapes (local processing) or whether the outside shapes (global processing) were squares or rectangles. Reaction time measures revealed that hemispheric differences were unrelated to the local or global processing requirements as well as the spatial frequency of the stimulus texture. A left hemisphere advantage generally was obtained across stimulus and processing conditions, with the pattern of task effects dependent on the specific stimuli employed. The results suggest that the overall stimulus shape rather than processing mode or specific spatial frequency is a primary determinant of hemispheric differences for visual information.     

A structural account of global and local processing

The order of processing, whether global forms are processed prior to local forms or vice versa, has been of considerable interest. Many current theories hold that the more perceptually conspicuous form is identified first. An alternative view is presented here in which the stuctural relations among elements are an important factor in explaining the relative speeds of global and local processing. We equated the conspicuity of the global and local forms in three experiments and still found advantages in the processing of global forms. Subjects were able to process the relations among the elements quickly, even before the elements themselves were identified. According to our alternative view, subjects created equivalence classes of similar and proximate local elements before identifying the constituent elements. The experiments required subjects to decide whether two displays were the same or different, and consequently, the results are relevant to work in higher-level cognition that stresses the importance of comparison processes (e.g., analogy and conceptual combination). We conclude by evaluating related work in higher-level cognition in light of our findings.     

Consequentiality and eyewitness person identification

The role of consequentiality in eyewitness person identification was examined. Subjects viewed a videotape depicting a simulated bank robbery and were then asked to identify the robber from a photographic lineup. Consequentiality was induced by leading some subjects to believe that the video tape was of an actual bank robbery, and that performance on the identification task would be influential in the suspected robber's court trial. The following manipulations were included to determine the interaction of consequentiality with commonly investigated eyewitness variables: lineup instructions, accountability and suspect presence in the lineup. In addition, the data were analysed for sex differences. Analyses of identification attempts and hits revealed interactions indicating that men were more influenced by consequentiality and lineup instructions than women. The results suggest that consequentiality does play a role in certain eyewitness identification situations.     

The confidence-accuracy relationship in eyewitness identification: the effects of reflection and disconfirmation on correlation and calibration

Participants viewed a simulated crime and attempted an identification from an 8-person target-present or target-absent lineup. The authors examined identification confidence-accuracy relations, contrasting a control condition (n = 310) with 2 manipulations designed to improve confidence scaling. Before indicating confidence, participants reflected on encoding and identification test conditions (n = 316) or suggested hypotheses about why their identification decision might have been wrong (n = 318). Confidence-accuracy correlations were weak and did not differ across conditions. However, for positive identifications, confidence and accuracy were well calibrated in the experimental conditions, although not in the control condition; similar patterns were observed for lineup rejections. Explanations for calibration differences in terms of discrimination difficulty, (mis)match between encoding and test stimuli, and the availability of confidence cues were advanced.     

Deconfounding the effects of congruency and task difficulty on hemispheric differences in global/local processing

Although it is often assumed that the left and right cerebral hemispheres are specialized for local and global processing, respectively, recent studies show that this difference mainly occurs if the responses to the two levels of a stimulus are conflicting. In the present study we examined whether the favorable effect of response conflicts is caused by the increased task difficulty in this situation. To this end, the response selection for nonconflicting stimuli was complicated by frequently changing the stimulus-response mappings. As a result, the reactions to nonconflicting stimuli were as slow as those to conflicting ones. Nevertheless, hemispheric differences were again restricted to the latter situation. This shows that increased task difficulty can not explain the modulating effect of response conflicts. The results support the alternative hypothesis that different representations are needed for the response selection for nonconflicting and conflicting stimuli, and that the hemispheres differ only with respect to the latter.     

Mental fatigue disturbs local processing more than global processing

Focusing of attention is influenced by external features such as the presence of global or local target stimuli, but also by motivation and mood states. In the current study, we examined whether working on cognitively demanding tasks for 2 h, which induces mental fatigue, subsequently had a differential effect on global and local processing. The results showed that, compared to non-fatigued participants, fatigued participants particularly displayed compromised local processing. This indicates that mental fatigue may also manifest itself as effects on attentional focusing. The findings of this study are in line with recent ideas about the nature of fatigue-related cognitive deficits, implying disturbances in the control over attention and behaviour.     

The effect of biased lineup instructions on eyewitness identification confidence

Although it is well‐known that biased lineup instructions (i.e., those that do not inform witnesses the perpetrator may not be in the lineup) inflate false identifications, their effects on witness confidence are less well understood due to methodological limitations of past studies. We report two studies that use novel methodologies to obviate these limitations. Study 1 (N = 177) demonstrated that biased lineup instructions increased witnesses' average estimates of the likelihood that a lineup member is guilty. Study 2 (N = 137) introduces a novel debiasing paradigm that allows a parsing of choosers into those who made an identification only because of the biased instructions (induced choosers), and those who would have chosen despite the instructions (inherent choosers). Biased lineup instructions inflated confidence only among induced choosers, but not among inherent choosers. Contrary to legal reasoning, witness confidence is an insufficient metric to determine the suggestiveness of biased instructions.     

The effects of realistic threat and group identification on social dominance orientation

Based on social identity and intergroup threat theories, we argue that social dominance orientation (SDO) can increase as a result of realistic threat, or perceived obstacles to the ingroup’s position and general welfare. However, this effect should be strongest among highly-identified group members, who are particularly concerned with protecting their ingroup against threat. Study 1 found that among non-Asian Americans, racial group identification moderated the relationship between perceptions of realistic threat from Asian Americans and SDO. Study 2 replicated Study 1 using an experimental, rather than correlational, design. Using different social groups, Study 3 showed that non-science college majors who identified strongly with their field of study exhibited higher SDO after being made to feel threatened by science majors. The results from these studies have implications for research on the meaning and antecedents of SDO.     

The effects of orientation on detection and identification of facial expressions of emotion

Signal detection procedures were used to examine the ability of participants to detect and label facial expressions of emotion in an upright or inverted orientation when the faces were rapid videotaped presentations. The detection and identification of facial expressions were remarkably accurate. In the upright orientation, the A′ measure of sensitivity was above .9 for detection and identification of all six facial expressions of emotion. Sensitivity to inverted expressions was diminished for all emotions; however, the extent of the decline in sensitivity depended upon the specific facial expression. If the expression was difficult to detect or label in the upright orientation, the sensitivity score was lower in the inverted orientation. An assessment of the errors made in the detection and labelling process allowed a demonstration of the specific facial expressions that were confused in either the upright or inverted orientation. The assessment of sensitivity and analysis of the errors suggests that the nature of perceptual processing of some, but not all, facial expressions is changed by inversion.     

The effects of social support on children's eyewitness testimony

Child witnesses often give only short accounts of witnessed events. Part of the reason for this failing centres on the stress present during an interview. The most obvious means of reducing stress in children, through the provision of social support, has typically been neglected in eyewitness research, presumably because of fears over children's excessive suggestibility. Social support is also believed to inhibit children during interviews. However, these fears appear to stem more from general suspicions about children's competencies rather than empirical findings. Studies are described which show that child witnesses express a strong desire for social support, and that support may be provided in a number of different ways, from peers as well as adults. It is argued that social support is one of the most unfairly neglected issues in eyewitness research, and the minimal evidence available suggests that allowing support may have a facilitative effect on task performance, including free-recall memory.