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.     

Why people rehearse their memories: Frequency of use and relations to the intensity of emotions associated with autobiographical memories

People may choose to rehearse their autobiographical memories in silence or to disclose their memories with other people. This paper focuses on five types of memory rehearsal: involuntary rehearsal, rehearsal to maintain an event memory, rehearsal to re-experience the emotion of an event, rehearsal to understand an event, or rehearsal for social communication. A total of 337 participants recalled event memories, provided estimates of how often each event was rehearsed and for what reason, and rated the affective characteristics of the events. Rehearsal frequency was highest for social communication and lowest for rehearsals aimed at understanding events. For many rehearsal types, rehearsal was more frequent for positive than negative events. Frequently rehearsed events tended to show less affective fading. The pattern changed when events were socially rehearsed. For positive events, increased social rehearsal was related to a reduction in affective fading. For negative events, increased social rehearsal was associated with increased affective fading.     

Self-events and other-events: Temporal dating and event memory

A diary methodology was used to assess factors related to temporal dating and cued recall of real-world events. In one diary, participants kept a record of unique personal autobiographical events. In a second diary, participants recorded unique events from the life of a friend or relation. At the time each event was recorded, participants rated the event’s pleasantness, person typicality, and degree of initial mental involvement in the event. At the end of the academic quarter, participants provided a recall rating, a rehearsal rating, a date estimate, and a report of the strategy used to estimate the date for each event. Results of regression analyses indicated that both self-events and other-events were characterized by superior memory for person-atypical events. Furthermore, there was a positivity bias in recall for self-events, but there was a negativity bias in recall for other-events. Mediational analyses indicated that the self-event positivity bias was due to enhanced mental involvement when the events occurred, whereas the other-event negativity bias was due to subsequent event rehearsal. The date estimation results indicated that self-event dating was more accurate and evinced less telescoping than other-event dating. Furthermore, the accuracy of date estimates was substantially mediated by event memory. However, mediational differences between self-events and other-events did not emerge. The theoretical implications of these results are discussed.     

Remembering September 11th: the role of retention interval and rehearsal on flashbulb and event memory

Retention interval and rehearsal effects on flashbulb and event memory for 11th September 2001 (9/11) were examined. In Experiment 1, college students were assessed three times (Groups 1 and 2) or once (Group 3) over 11 weeks. In Experiment 2, three new groups assessed initially at 23 weeks (Group 4), 1 year (Group 5), or 2 years (Group 6) were compared at 1 year and at 2 years with subsamples of those assessed previously. No effects of retention interval length or rehearsal were found for flashbulb memory, which contained details at each assessment. Event memory, but not consistency, was detrimentally affected by long retention intervals, but improved with rehearsal. Recall was higher for the reception event than for the main events. Also, consistency from 1 day to 11 weeks, but not 1 year to 2 years, was higher for flashbulb memory than for event memory. Event recall was enhanced when respondents conceived of their memory as vivid, frozen, and encompassing a longer period of time. Positive correlations were found for event memory with confidence in accuracy and with rehearsal through discussion at 2 years.     

Judgement of lateral orientation for previously seen and unseen photographs of faces

In Study 1, 56 undergraduates judged whether each member of two sets of unseen photographs of faces was shown in the original or reversed orientation. Performance was at chance level, indicating that they could not perform this task. In Studies 2 and 3, the first of which involved unanalyzed data from previously-published work, an investigation was made of identification of orientation for faces which had been laterally reversed in the course of experiments on recognition memory. For a total of 406 subjects, over-all identification accuracy was about 60%, which was above chance. However, subjects were correct more often on normal (unchanged) than on reversed (changed) faces and were generally more likely to identify a face as normal when they were certain than when they were uncertain in their initial recognition judgement. It was concluded that identification performance could largely be accounted for by a response strategy model in which subjects judged orientation on the basis of their subjective familiarity with the face. Together, these studies demonstrate that subjects could not usually detect the lateral orientation of previously-seen or of unseen photographs of faces.     

Verbal recoding of visual stimuli impairs mentalimagetransformations

Two experiments were carried out to test the hypothesis that verbal recoding of visual stimuli in short-term memory influences long-term memory encoding and impairs subsequent mental image operations. Easy and difficult-to-name stimuli were used. When rotated 90 degrees counterclockwise, each stimulus revealed a new pattern consisting of two capital letters joined together. In both experiments, subjects first learned a short series of stimuli and were then asked to rotate mental images of the stimuli in order to detect the hidden letters. In Experiment 1, articulatory suppression was used to prevent subjects from subvocal rehearsal when learning the stimuli, whereas in Experiment 2, verbal labels were presented with each stimulus during learning to encourage a reliance on the verbal code. As predicted, performance in the imagery task was significantly improved by suppression when the stimuli were easy to name (Experiment 1) but was severely disrupted by labeling when the stimuli were difficult to name (Experiment 2). We concluded that verbal recoding of stimuli in short-term memory during learning disrupts the ability to generate veridical mental images from long-term memory.     

Eye Remember What Happened: Eye‐Closure Improves Recall of Events but not Face Recognition

Eye‐closure improves event recall. We investigated whether eye‐closure can also facilitate subsequent performance on lineup identification (Experiment 1) and face recognition tasks (Experiment 2). In Experiment 1, participants viewed a theft, recalled the event with eyes open or closed, mentally rehearsed the perpetrator's face with eyes open or closed, and viewed a target‐present or target‐absent lineup. Eye‐closure improved event recall, but did not significantly affect lineup identification accuracy. Experiment 2 employed a face recognition paradigm with high statistical power to permit detection of potentially small effects. Participants viewed 20 faces and were later asked to recognize the faces. Thirty seconds before the recognition task, participants either completed an unrelated distracter task (control condition), or were instructed to think about the face with their eyes open (rehearsal condition) or closed (eye‐closure condition). We found no differences between conditions in discrimination accuracy or response criterion. Potential explanations and practical implications are discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of generative processes on probe identification time

Studies of character classification have shown that reaction time is reduced when the probe is the same as the last-rehearsed target item. If rehearsal functions as a generative process to reduce response time by stimulus activation, comparable results should be obtained if the task is changed from probe classification to probe naming. A letter identification baseline was obtained in Session 1 where subjects named single probe letters as quickly as possible. In Sessions 2 and 3, each probe letter was preceded by a target of three to five letters, which were rehearsed individually prior to the probe, and subjects reported their last rehearsal after naming the probe. The results showed that (1) naming latencies were longer in Sessions 2 and 3 than in Session 1, suggesting that rehearsal requires conscious attention; (2) letter probes that matched the last-rehearsed target item were named faster than those that were different; (3) when performance was examined in terms of the rehearsal distance between the target items and probe, target set size had no effect on probe identification time. Generative processes were suggested to influence probe encoding time through stimulus preprocessing.     

Item identification time and rehearsal rate as predictors of memory span in children

According to the working memory model of Baddeley and Hitch (1974), the sensitivity of memory span to word length arises from the time taken to rehearse items in a speech-based “articulatory loop”. Alternatively, it has been suggested that the word-length effect may result from differences in the speed of perceptual processes of item identification. Changes in the speed of rehearsal and of item identification have also been claimed to contribute to the growth of memory span that is seen in development. In order to compare these two variables directly, groups of children aged 8 and 11 were assessed on memory span for words of one, two, and three syllables; span under articulatory suppression; rehearsal rate; and item identification time. Span was found to be a linear function of rehearsal rate across differences in both word length and age. The word-length effect was unrelated to item identification time and was diminished by articulatory suppression. These results show that the word-length effect reflects rehearsal and not item identification processes. However, the results also suggest that changes in item identification time contribute to developmental differences in span when articulation is suppressed. A distinction between item identification and rehearsal effects can be readily interpreted in terms of the working memory model if it is assumed that they indicate the efficiency of different subsystems involved in span.     

Rehearsal,generative processes,and the activation of underlying stimulus representations

Previous research found that subjects engaged in mental rehearsal could reduce stimulus encoding time in classification and identification tasks by generating an appropriate representation of the probe stimulus prior to its presentation. The present experiment examined the types of representational codes activated by generative processes in character classification. Numerical stimuli were employed which could differ visually, yet have the same name and meaning (e.g., TWO, 2, II, &.). The results indicate that generative processes may activate visual and nonvisual memory codes prior to the encoding of an external stimulus. Effects of generative processes were discussed in terms of an activation model which defines the function of rehearsal in perceptual processing. Attention, through rehearsal, activates stimulus representations which are described by distributions of activation which change continuously over time. The momentary state of each distribution determines the rate of stimulus encoding.     

Distinct processes shape flashbulb and event memories

In the present study, we examined the relation between memory for a consequential and emotional event and memory for the circumstances in which people learned about that event, known as flashbulb memory. We hypothesized that these two types of memory have different determinants and that event memory is not necessarily a direct causal determinant of flashbulb memory. Italian citizens (N = 352) described their memories of Italy’s victory in the 2006 Football World Cup Championship after a delay of 18 months. Structural equation modeling showed that flashbulb memory and event memory could be clearly differentiated and were determined by two separate pathways. In the first pathway, importance predicted emotional intensity, which, in turn, predicted the frequency of overt and covert rehearsal. Rehearsal was the only direct determinant of vivid and detailed flashbulb memories. In the second pathway, importance predicted rehearsal by media exposure, which enhanced the accuracy and certainty of event memory. Event memory was also enhanced by prior knowledge. These results have important implications for the debate concerning whether the formation of flashbulb memory and event memory involve different processes and for understanding how flashbulb memory can be simultaneously so vivid and so error-prone.     

Effects of event valence on long-term memory for two baseball championship games

We investigated how event valence affected accuracy and vividness of long-term memory for two comparable public events. In 2008, 1,563 fans answered questions about objective details concerning two decisive baseball championship games between the Yankees (2003 winners) and the Red Sox (2004 winners). Both between- and within-groups analyses indicated that fans remembered the game their team won significantly more accurately than the game their team lost. Fans also reported more vividness and more rehearsal for the game their team won. We conclude that individuals rehearse positive events more than comparable negative events, and that this additional rehearsal increases both vividness and accuracy of memories about positive events. Our results differ from those of prior studies involving memories for negative events that may have been unavoidably rehearsed; such rehearsal may have kept those memories from fading. Long-term memory for an event is determined not only by the valence of the event, but also by experiences after the event.     

Pictorial rehearsal

Subjects were presented with a sequence of picture-word items. The pictures were line drawings of common objects, and the words were the names of the objects. Half of the items were followed quickly by the next item, and the other half by a 15-sec “rehearsal interval.” The subjects were told to use these intervals to rehearse the item just presented, either by saying the word over and over to themselves or by maintaining the picture before the mind’s eye. There followed a test in which each item from the study list was cued with a fragment of either the picture or the name. Consistent with previous findings, identification was more probable for fragments of items that had been followed by a rehearsal interval. In addition, this advantage was found to be greater when the type of cue matched the mode of rehearsal that the subject had been instructed to adopt; there was in fact little, if any, advantage of rehearsal when cue and mode of rehearsal mismatched. This pattern of results suggests functionally distinct pictorial and verbal modes of rehearsal that serve not only to maintain information in conscious mind but also to build up memory proper.     

Some relevant factors in the transfer of material from short-term to long-term memory

The relationship between short-term memory (STM) and long-term memory (LTM) for digits was investigated by means of a Hebb-type experiment, viz. a presentation of a series of nine-digit numbers, in which a certain number recurs at intervals. Improvement in performance, with regard to the critical, or recurring, number was found when the rehearsal grouping was three-three-and-three, but was absent when there were no opportunities for rehearsal or when the rehearsal strategy was grouping five-and-four or searching for systematic numbers.

However, if an overt recall response was given on each occasion the recurring number was presented, improved performance was found even with rehearsal stratgegy five-and-four.

The conclusion was drawn that rehearsal is the main transferring mechanism from STM to LTM, with the occurrence of an over recall response as a subsidiary factor.     

Conditions and consequences of maintenance rehearsal.

The present experiments investigated the idea that the anticipated delay to initial recall governs whether a subject will rely on elaborative or maintenance rehearsal. In agreement with earlier research, the results suggested that maintenance rehearsal is used only when words can be rehearsed up to the moment of recall. A novel finding concerned the accessibility of the items processed in that way. When subjects were explicitly asked to recall those items first in final free recall, they were as likely to be recalled as items that had been processed elaboratively. This finding suggests that even rote rehearsal creates an accessible memory trace, albeit one that is most efficiently accessed by contextual rather than semantic cues.     

Rehearsal strategies during motor-sequence learning in old age: execution vs motor imagery

Motor imagery and action-based rehearsal were compared during motor sequence-learning by young adults (M = 25 yr., SD = 3) and aged adults (M = 63 yr., SD = 7). General accuracy of aged adults was lower than that of young adults (F(1,28) = 7.37, p =.01) even though working-memory capacity was equivalent in the two groups. Motor imagery and rehearsal by action increased accuracy in both age groups, compared with minimization of opportunity for rehearsal (F(1,28) = 30.95, p < .001), but no interaction was found with age group, which suggests that young and aged adults were equally capable of motor imagery and action-based rehearsal. It was assumed that differences in performance between young and aged participants related to the formation of mental representations of sequences and integration of new elements into these representations rather than the capacity for motor imagery or rehearsal by action per se. The current study was exploratory and involved a relatively small sample of 15 participants per age group. Caution must be taken when considering the results.     

Determinants of spatial priming in environmental memory

Spatial priming in recognizing objects in experimentally learned environments has been proposed as strong evidence for spatial organization of environmental memory. However, in all studies showing recognition priming effects, encoding and rehearsal contiguity may have coincided with spatial proximity, and thus priming may have been due to temporal associations formed during rehearsal, not encoded spatial relations per se. We investigated this question in four experiments, using a trip trial learning method in which temporal contiguity and spatial relations were independent. In Experiment 1, no spatial priming in recognition was found, even though indirect evidence suggested that subjects had encoded spatial relations. In Experiment 2, the trip trial method was compared with the free study procedure commonly used in previous priming studies. Spatial priming occurred only for free study subjects, even though the two groups were equivalent on direct measures of encoding accuracy. In Experiment 3, spatial priming in recognition was obtained with a modification of the trip trial method in which temporal and spatial contiguity were deliberately confounded. In Experiment 4, the unmodified trip trial method produced spatial priming in a location-decision task. Taken together, our results suggest that environmental memory may be spatially organized, but retrieval of object identities does not necessarily activate encoded spatial relations.     

Recognizing faces in and out of context

Two experiments are reported which examined the influence of context on face recognition accuracy for novel and familiar faces respectively. Context was manipulated by varying the physical background against which the faces appeared. In Experiment I, 80 student subjects observed 18 faces before attempting to recognize them in a sequence of 36 alternatives. For half the subjects, the backgrounds changed from study to test, while for the remainder they stayed the same. In addition, for half the subjects, both the pose and expression of the face also changed, while for the others it remained constant. Changes in pose plus expression and context significantly reduced recognition accuracy for the target faces. Experiment II used an identical design, except that the faces of celebrities replaced the novel faces. The influence of context was eliminated but the effects of pose and expression were maintained. However, when only faces which were actually identified by subjects were considered, the effects of pose and expression, too, were eliminated. The significance of these findings for theories of contextual memory are discussed.