Environmental context-dependent eyewitness recognition

The present study helped resolve the apparent conflict between many laboratory list-learning studies, which have not found environmental context-dependent recognition memory, and staged field studies (e.g. Malpass and Devine, 1981), whose results with ‘guided memory’ techniques suggest that eyewitness face recognition should depend upon environmental context reinstatement. It was found in two different experiments that, relative to testing in a new place, returning participants to the environment where a live staged event had occurred improved performance on identification of a confederate's face (i.e., hit rate). Although physical reinstatement improved identification performance in Experiment 1, mental reinstatement instructions to subjects tested in a new environment did not improve identification performance over an uninstructed group. The environmental reinstatement effect did not interact with test delay or confederate. In Experiment 2 it was found that environmental reinstatement improved accuracy (hit rate and foil identification rate) when the correct target was present in the test line-up, and that false identifications were not significantly affected by contextual manipulations when the correct target was absent from the line-up. The results provide an empirical basis for the hypothesis that returning to the scene of an event improves eyewitness face recognition.     

Super-recognisers: Face recognition performance after variable delay intervals

Outstanding long-term face recognition of suspects is a hallmark of the exceptionally skilled police ‘super-recognisers’ (SRs). Yet, research investigating SR's memory for faces mainly employed brief retention intervals. Therefore, in Experiment 1, 597 participants (121 SRs) viewed 10 target videos and attempted identification of targets from 10 target-present line-ups after 1–56 days. In Experiment 2, 1,421 participants (301 SRs) viewed 20 target videos, and after a baseline of no delay to 28 days,—10 target-present and 10 target-absent line-ups, to assess correct line-up rejections. Overall, delay positively correlated with hits but not with correct rejections. Most, but not all SRs, made more correct identifications and correct rejections than controls at all retention intervals, demonstrating that many SRs possess enhanced long-term face memory. This research adds to the knowledge of SR's skillsets, and enhances the case for the selection of SRs to identity critical roles—particularly policing.     

Early Stage Alzheimer's Disease Disrupts Encoding of Contextual Information

Two experiments examined whether impairments in recognition memory in early stage Alzheimer's disease (AD) were due to deficits in encoding contextual information. Normal elderly (NE) and patients diagnosed with mild stage AD learned one of two tasks. In Experiment 1 correct recognition memory required participants to remember not only what items they had experienced on a given trial but also when they had experienced them; Experiment 2 required that participants remember only what they had seen, not when they had seen it. Large recognition memory differences were found between the AD and NE groups in the experiment where time tagging was crucial for successful performance. An error analysis indicated that this was not due to the perseveration of previous learned responses. In Experiment 2, the only requisite for successful recognition was remembering what one had experienced; memory of the temporal record was not necessary for successful performance. In this instance, recognition memory for the NE and AD groups was identical. Taken together these results suggest that memory deficits found in early stage AD are partly due to impaired processing of contextual cues that provide crucial information about when events occur.     

Directed forgetting of a single item

In two experiments, we investigated directed forgetting of a single item. We presented participants with two phone numbers to remember and instructed half of the participants to forget the first phone number. The first number was either learned on a single trial (Experiment 1) or on three trials (Experiment 2). In Experiment 1, there was evidence of directed forgetting as a result of differential encoding; the forget instruction affected recall and recognition for both phone numbers. In Experiment 2, the evidence favored differential rehearsal because the forget instruction affected recall but not recognition. These results indicate that instructions to forget can affect memory of single items.     

Explicit awareness supports conditional visual search in the retrieval guidance paradigm

In four experiments we explored whether participants would be able to use probabilistic prompts to simplify perceptually demanding visual search in a task we call the retrieval guidance paradigm. On each trial a memory prompt appeared prior to (and during) the search task and the diagnosticity of the prompt(s) was manipulated to provide complete, partial, or non-diagnostic information regarding the target's color on each trial (Experiments 1–3). In Experiment 1 we found that the more diagnostic prompts was associated with faster visual search performance. However, similar visual search behavior was observed in Experiment 2 when the diagnosticity of the prompts was eliminated, suggesting that participants in Experiment 1 were merely relying on base rate information to guide search and were not utilizing the prompts. In Experiment 3 participants were informed of the relationship between the prompts and the color of the target and this was associated with faster search performance relative to Experiment 1, suggesting that the participants were using the prompts to guide search. Additionally, in Experiment 3 a knowledge test was implemented and performance in this task was associated with qualitative differences in search behavior such that participants that were able to name the color(s) most associated with the prompts were faster to find the target than participants who were unable to do so. However, in Experiments 1–3 diagnosticity of the memory prompt was manipulated via base rate information, making it possible that participants were merely relying on base rate information to inform search in Experiment 3. In Experiment 4 we manipulated diagnosticity of the prompts without manipulating base rate information and found a similar pattern of results as Experiment 3. Together, the results emphasize the importance of base rate and diagnosticity information in visual search behavior. In the General discussion section we explore how a recent computational model of hypothesis generation (HyGene; Thomas, Dougherty, Sprenger, & Harbison, 2008), linking attention with long-term and working memory, accounts for the present results and provides a useful framework of cued recall visual search.     

The importance of cue familiarity and cue distinctiveness in prospective memory

Abstract

Both retrospective cued-memory tasks and event-based prospective memory tasks require that cue and target information be associated, and that aspects of that association be reinstated for successful remembering. These functional similarities between retrospective memory and prospective memory were the bases for the hypothesis that the familiarity and the distinctiveness of the target event (cue) would influence prospective memory performance. Experiment 1, focusing on target familiarity, found a nominal advantage in prospective memory with unfamiliar target events. Experiment 2 showed a significant benefit for unfamiliar target events, as well as for target events that were distinctive relative to the local context. Additionally, prospective memory performance did not reliably correlate with explicit retrospective memory tasks (recall and recognition), but did correlate with an indirect retrospective memory task (word fragment completion). This pattern suggests and helps specify the general view that prospective memory processes may be similar to those involved in both direct and indirect tests of retrospective memory.     

Verbal overshadowing of visual memories: some things are better left unsaid

It is widely believed that verbal processing generally improves memory performance. However, in a series of six experiments, verbalizing the appearance of previously seen visual stimuli impaired subsequent recognition performance. In Experiment 1, subjects viewed a videotape including a salient individual. Later, some subjects described the individual's face. Subjects who verbalized the face performed less well on a subsequent recognition test than control subjects who did not engage in memory verbalization. The results of Experiment 2 replicated those of Experiment 1 and further clarified the effect of memory verbalization by demonstrating that visualization does not impair face recognition. In Experiments 3 and 4 we explored the hypothesis that memory verbalization impairs memory for stimuli that are difficult to put into words. In Experiment 3 memory impairment followed the verbalization of a different visual stimulus: color. In Experiment 4 marginal memory improvement followed the verbalization of a verbal stimulus: a brief spoken statement. In Experiments 5 and 6 the source of verbally induced memory impairment was explored. The results of Experiment 5 suggested that the impairment does not reflect a temporary verbal set, but rather indicates relatively long-lasting memory interference. Finally, Experiment 6 demonstrated that limiting subjects' time to make recognition decisions alleviates the impairment, suggesting that memory verbalization overshadows but does not eradicate the original visual memory. This collection of results is consistent with a recording interference hypothesis: verbalizing a visual memory may produce a verbally biased memory representation that can interfere with the application of the original visual memory.     

Massed versus distributed exposure and imaging of faces: Changing the test view

This research examined the effects of massed versus distributed exposure and imaging of faces, and the effects of changing the study-to-test view on subsequent recognition performance. The massed procedure consisted of individual faces exposed once for 6 s, followed by a 30 s off period. The distributed procedure consisted of faces exposed three times for 2 s, followed by a 10 s off period after each exposure. During the off periods, groups of participants either imaged the previous face, imaged another face, or performed an irrelevant letter-search task. Results showed that distributed exposure and post-exposure imaging of target faces facilitated recognition, but these effects primarily occurred when the same facial view was given at both study and test. Recognition diminished when the target was presented in a different view at test, but when combined with distributed presentation and target imaging, performance was enhanced. Implications for suspect identification and recognition of other kinds of complex visual stimuli are discussed.     

Probing memory with conceptual cues at multiple retention intervals: a comparison of forgetting rates on implicit and explicit tests

The time courses for implicit and explicit conceptual tests of memory were compared in two experiments. In Experiment 1, participants encoded target words by judging the apparent pleasantness of their meaning. Immediately thereafter or 48 h later, retrieval cues were presented to different groups of participants for either an implicit or an explicit free-association task. Whereas explicit test performance showed a decline over the 48-h delay, implicit test performance was statistically unaltered. In Experiment 2, memory was tested at five retention intervals, lasting up to 3 weeks. The forgetting functions of both implicit and explicit tests conformed to a logarithmic function. Despite the large conceptual priming effect, which resulted from relational encoding instructions, implicit memory performance still declined at a much slower rate than did performance on the cued-recall test. We argue that because nominal conceptual cues were held constant across the implicit and the explicit conditions, the observed dissociation in performance supports a memory systems approach.     

Disproportionate deficit in associative recognition relative to item recognition in global amnesia

In two experiments, we tested the hypothesis that medial temporal lobe (MTL) amnesic patients and, likewise, diencephalic (DNC) amnesic patients evidence a disproportionate deficit in memory for associations in comparison with memory for single items. In Experiment 1, we equated item recognition in amnesic and control participants and found that, under these conditions, associative recognition remained impaired both for MTL patients and for DNC patients. To rule out an alternative interpretation of the results of Experiment 1, in Experiment 2 we compared the performance of amnesic and control participants on a one-item recognition task and a two-item recognition task that required no memory for the association between members of word pairs. In the MTL group, when single-item recognition was equated to that of the controls, two-item nonassociative pair memory was equivalent as well. In the DNC group, nonassociative pair memory was impaired, but this impairment did not fully account for the impairment in associative memory. These findings indicate that memory for novel associations between items is disproportionately impaired in comparison with memory for single items in amnesia.     

Searching for faces in crowd chokepoint videos

Investigations of face identification have typically focussed on matching faces to photographic IDs. Few researchers have considered the task of searching for a face in a crowd. In Experiment 1, we created the Chokepoint Search Test to simulate real-time search for a target. Performance on this test was poor (39% accuracy) and showed moderate associations with tests of face matching and memory. In addition, trial-level confidence predicted accuracy, and for those participants who were previously familiar with one or more targets, higher familiarity was associated with increased accuracy. In Experiment 2, we found improvements in performance on the test when three recent images of the target, but not three social media images, were displayed during searches. Taken together, our results highlight the difficulties inherent in real-time searching for faces, with important implications for those security personnel who carry out this task on a daily basis.     

Tactile memory of deaf-blind adults on four tasks

The performance of ten deaf-blind and ten sighted-hearing participants on four tactile memory tasks was investigated. Recognition and recall memory tasks and a matching pairs game were used. It was hypothesized that deaf-blind participants would be superior on each task. Performance was measured in terms of the time taken, and the number of items correctly recalled. In Experiments 1 and 2, which measured recognition memory in terms of the time taken to remember target items, the hypothesis was supported, but not by the length of time taken to recognize the target items, or for the number of target items correctly identified. The hypothesis was supported by Experiment 3, which measured recall memory, with regard to time taken to complete some of the tasks but not for the number of correctly recalled positions. Experiment 4, which used the matching pairs game, supported the hypothesis in terms of both time taken and the number of moves required. It is concluded that the deaf-blind people's tactile encoding is more efficient than that of sighted-hearing people, and that it is probable that their storage and retrieval are normal.     

Reducing cognitive complexity in a hypothetico-deductive reasoning task

The confusion/non-consequential thinking explanation proposed by Newstead, Girotto, and Legrenzi (1995) for poor performance on Wason's THOG problem (a hypothetico-deductive reasoning task) was examined in three experiments with 300 participants. In general, as the cognitive complexity of the problem and the possibility of non-consequential thinking were reduced, correct performance increased. Significant but weak facilitation (33-40% correct) was found in Experiment 1 for THOG classification instructions that did not include the indeterminate response option. Substantial facilitation (up to 75% correct) was obtained in Experiment 2 with O'Brien et al.'s (1990) one-other-THOG classification instruction. In Experiment 3, a revised version of O'Brien et al.'s pre-test problem format also led to substantial facilitation, even with the use of the standard three-choice THOG classification instruction. These findings are discussed in terms of Newstead et al.'s theoretical proposal and possible attentional factors.     

Face value: testing the utility of contextual face cues for face recognition

The presence of multiple faces during a crime may provide a naturally-occurring contextual cue to support eyewitness recognition for those faces later. Across two experiments, we sought to investigate mechanisms underlying previously-reported cued recognition effects, and to determine whether such effects extended to encoding conditions involving more than two faces. Participants studied sets of individual faces, pairs of faces, or groups of four faces. At test, participants in the single-face condition were tested only on those individual faces without cues. Participants in the two and four-face conditions were tested using no cues, correct cues (a face previously studied with the target test face), or incorrect cues (a never-before-seen face). In Experiment 2, associative encoding was promoted by a rating task. Neither hit rates nor false-alarm rates were significantly affected by cue type or face encoding condition in Experiment 1, but cuing of any kind (correct or incorrect) in Experiment 2 appeared to provide a protective buffer to reduce false-alarm rates through a less liberal response bias. Results provide some evidence that cued recognition techniques could be useful to reduce false recognition, but only when associative encoding is strong.     

Face recognition and aging: Effects of target age and memory load

In the present study, we investigated age-related decline in face recognition memory and whether this decline is moderated by the age of the target faces and by the number of faces that the participant must learn (memory load). Thirty-two participants in each of three age groups (18-39 years, 60-75 years, and 76-96 years) completed a face recognition task. Signal detection analyses confirmed that face recognition accuracy declined with age. However, this finding was qualified by an interaction between participant age and target age, which revealed that the age-related decline in face recognition accuracy occurred only for young target faces. Increased memory load was associated with comparable performance decrements across all age groups. However, memory load appears not to be the cause of these decrements. Instead, they appear to be a product of recognition load (the number of stimuli presented in the recognition phase).     

Signing enhances memory like performing actions

In three experiments, we investigated the influence of the overt performance of signs on memory. Deaf and hearing participants studied lists of action phrases (Experiment 1) or nouns (Experiment 2) under standard verbal instruction, under the instructions to sign the verbal phrase, to symbolically perform the denoted action, or to carry out a prototypical action corresponding to each noun. Higher recall and recognition performances were observed when actions were performed than in the verbal encoding condition, and signing was as effective for memory as was enactment. Thus, overt signing can induce an enactment effect. In contrast, Experiment 3 demonstrated that performing an unrelated action did not. A unique but unrelated action was not memory efficient.     

An individual difference analysis of false recognition

Two studies with moderately large samples of participants were conducted to examine correlates of false recognition. In Experiment 1 false recognition of words was found to be a robust and reliable phenomenon at the level of individuals, and the tendency to classify critical lures as old was more closely related to the correct classification of old items as old than to the incorrect classification of unrelated new items as old. False recognition was not significantly related to any of the cognitive abilities that were assessed, including episodic memory, or to other factors such as personality and chronic mood. In Experiment 2 these findings were extended to include dot pattern and face stimuli. Although measures of veridical memory were significantly correlated across the different types of stimulus material, false recognition rates only had modest and generally not significant correlations, which suggests that the tendency to produce false recognitions may be a task-specific characteristic of individuals.     

Cued Memory Collaboration: Effects of Friendship and Type of Retrieval Cue

The effects of friendship and collaboration on memory retrieval were investigated in two experiments. The net negative effect of collaboration in memory retrieval and the effect of friendship were studied within a cueing framework. The aim of the study was to investigate the reduced cue effectiveness hypothesis. In Experiment 1, dyadic retrieval was compared to that of a nominal group (a pooled score from two individuals working individually). The task was to encode and retrieve 90 words individually or dyadically. The retrieval phase was supported by cues produced by others or produced by the participants themselves (individually or dyadically). In Experiment 2, friends were compared to non-friends in a memory retrieval phase. All participants retrieved alone in Experiment 2. The results of Experiment 1 revealed that dyadic retrieval suffered compared to nominal group retrieval and that no such discrepancies were found for retrieval with cues produced by others. In Experiment 2, friends could help each other towards successful retrieval to a greater extent than non-friends, and “for others” instructions increased retrieval performance as well. These findings replicate previous studies by Andersson and Ronnberg (1995, 1996), and advance the understanding of collaborative memory; that is, net negative effects of collaboration can be explained in terms of the reduced cue effectiveness hypothesis.     

Making related errors facilitates learning,but learners do not know it

Producing an error, so long as it is followed by corrective feedback, has been shown to result in better retention of the correct answers than does simply studying the correct answers from the outset. The reasons for this surprising finding, however, have not been investigated. Our hypothesis was that the effect might occur only when the errors produced were related to the targeted correct response. In Experiment 1, participants studied either related or unrelated word pairs, manipulated between participants. Participants either were given the cue and target to study for 5 or 10 s or generated an error in response to the cue for the first 5 s before receiving the correct answer for the final 5 s. When the cues and targets were related, error-generation led to the highest correct retention. However, consistent with the hypothesis, no benefit was derived from generating an error when the cue and target were unrelated. Latent semantic analysis revealed that the errors generated in the related condition were related to the target, whereas they were not related to the target in the unrelated condition. Experiment 2 replicated these findings in a within-participants design. We found, additionally, that people did not know that generating an error enhanced memory, even after they had just completed the task that produced substantial benefits.