Dissociating familiarity from recollection using rote rehearsal

Recollection-based recognition memory judgments benefit greatly from effortful elaborative encoding, whereas familiarity-based judgments are much less sensitive to such manipulations. In this study, we have examined whether rote rehearsal under divided attention might produce the opposite dissociation, benefiting familiarity more than recollection. Subjects rehearsed word pairs during the "distractor" phase of a working memory span task, and were then given a surprise memory test for the distractor items at the end of the experiment. Experiment 1 demonstrated that increasing rehearsal elevated the recognition rate for intact and rearranged pairs, but neither associative recognition accuracy nor implicit fragment completion benefited from rehearsal. The results suggest that rote rehearsal leads to a greater increase in familiarity than in recollection, and that the increase in observed familiarity cannot be attributed to effects of repetition priming. In Experiment 2, we tested item recognition with the remember/know procedure, and the results supported the conclusions of Experiment 1. Moreover, a signal detection model of remember/know performance systematically overpredicted rehearsal increases in remember rates, and this worsened when high-rehearsal items were assumed to be more variable in strength. The results suggest that rote rehearsal can dissociate familiarity from recollection at the time of encoding and that item recognition cannot be fully accommodated within a one-dimensional signal detection model.     

Implicit memory for novel associations between pictures: effects of stimulus unitization and aging

Studies of implicit memory for novel associations have focused primarily on verbal materials and have highlighted the contribution of conceptually unitized representations to such priming. Using pictorial stimuli in a perceptual identification task, we examined whether new association priming can occur at a purely perceptual level. By manipulating the spatial contiguity of stimuli, we also evaluated whether such priming requires the creation of perceptually unitized representations. Finally, we examined the status of such priming in aging. In Experiment 1, we found that spatial contiguity of stimuli is not necessary for novel pictorial association priming to emerge, although such contiguity does enhance the magnitude of associative priming. In Experiment 2, we found that new association priming is age invariant, regardless of spatial contiguity. In Experiment 3, we provide additional evidence that pictorial association priming is perceptually based. These findings expand the scope and delineate the conditions of novel association priming and inform theories about the nature of implicit memory for new associations.     

Mental representations of spatial and nonspatial relations

Four experiments investigated the representation and integration in memory of spatial and nonspatial relations. Subjects learned two-dimensional spatial arrays in which critical pairs of object names were semantically related (Experiment 1), semantically and episodically related (Experiment 2), or just episodically related (Experiments 3a and 3b). Episodic relatedness was established in a paired-associate learning task that preceded array learning. After learning an array, subjects participated in two tasks: item recognition, in which the measure of interest was priming; and distance estimation. Priming in item recognition was sensitive to the Euclidean distance between object names and, for neighbouring locations, to nonspatial relations. Errors in distance estimations varied as a function of distance but were unaffected by nonspatial relations. These and other results indicated that nonspatial relations influenced the probability of encoding spatial relations between locations but did not lead to distorted spatial memories.     

Constraints on priming in spatial memory: Naturally learned versus experimentally learned environments

In four experiments, we explored constraints on priming in spatial memory. In Experiments 1 and 2, subjects who were familiar with the locations of buildings on the Vanderbilt campus participated in a recognition test. The subjects' task was to decide whether or not named buildings were on the campus. Foils in this recognition test were realistic but fictional names of buildings. In principle, the subjects could have performed this task without using spatial knowledge; in fact, they must not have used spatial knowledge, because there was no evidence of priming in recognition as a function of the spatial relations between buildings on the campus. This result differs from those obtained in earlier experiments that have examined memory of spatial layouts learned in laboratory settings. In Experiment 3, the fictional foils were replaced by names of buildings in an area of the campus separated geographically from the main campus. Evidently, this change induced subjects to retrieve spatial knowledge, because the spatial priming effect materialized. A fourth experiment replicated the above findings in a single experiment and demonstrated that spatial priming could be obtained when the configuration of buildings was learned experimentally. These results are explained by appealing to the "decontextualization" that takes place in memory over time.     

Spatio-temporal working-memory and short-term object-location tasks use different memory mechanisms

Spatial short-term memory for objects' locations was investigated in a spatial relocation task. During maintenance, dynamic visual noise or spatial tapping were administered as visual or spatial secondary tasks, respectively. Because memory for location should tap the visual component of working memory, a visual but not a spatial secondary task should impair location memory. In fact, neither of the tasks impaired memory (Experiment 1), although the expected dissociation between visual and spatial components was clearly confirmed for a spatio-temporal main task (Corsi test) (Experiment 2). We then contrasted location memory for pictures of objects and of nonsense figures under visual interference. Real objects were relocated much better than nonsense figures, and visual noise was again ineffective (Experiment 3). When spatial tapping was combined with the same material (Experiment 3a), again no influence on memory for locations of objects was observed and only a small influence on remembering nonsense figures. We suggest that the Corsi and the relocation VSWM-tasks use different memory mechanisms. The configuration of objects is reconstructed from perceptual records in an episodic buffer, provided by the same structures that enable visual memory after longer intervals. Rehearsal is not necessary for the persistence of these traces. In contrast, in the Corsi task remembering, a temporal sequence across homogeneous locations needs spatio-temporal marking and therefore active rehearsal of the locations by shifting spatial attention. A spatially demanding secondary task during retention interrupts this rehearsal.     

联想启动与知觉启动的比较研究

采用快速命名方法探讨不同加工水平对联想启动效应的影响。被试分别在深、浅加工条件下学习一系列颜色词,然后完成颜色命名和再认任务,并设立词命名任务,以比较联想启动和知觉启动的异同。结果表明,在颜色命名任务中,深、浅加工条件下均可形成对颜色词的启动效应,但浅加工条件下的再认成绩明显低于深加工,出现了联想启动和再认的分离现象。词命名表现出与颜色命名相似的结果,但它们在有意识回忆方面仍存在一定的差异,提示知觉表征系统单独并不能支持联想启动,联想启动可能是多个记忆系统共同作用的结果。     

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.     

Temporal order judgments with amnesia

The hypothesis that patients with anterograde amnesia fail to recognize the temporal relations among recognizable past events was evaluated. Experiment 1 showed that order recognition for words in a list was at chance levels even though event recognition was significantly above chance. The same pattern did not obtain for intact adults. Experiment 2 examined event and order recognition for news events. Amnesics' event recognition for news events was quite accurate and comparable to controls, yet their order recognition was significantly below that of controls, again at chance levels. It is argued that the failure to encode the temporal relations among events has broad consequences for memory performance in general.     

Repetition Priming Follows Spontaneous but not Prompted Recognition of Familiar Faces

Reaction times to make a familiarity decision to the faces of famous people were measured after recognition of the faces in a pre-training phase had occurred spontaneously or following prompting with a name or other cue. At test, reaction times to familiar faces that had been recognized spontaneously in the pre-training phase were significantly facilitated relative to an unprimed comparison condition. Reaction times to familiar faces recognized only after prompting in the pre-training phase were not significantly facilitated. This was demonstrated both when a name prompt was used (Experiments 1 and 3) and when subjects were cued with brief semantic information (Experiment 2).

Repetition priming was not found to depend on prior spontaneous recognition per se. In Experiment 3, spontaneously recognizing a familiar face did not prime subsequent familiarity judgements when the same face had only been identified following prompting on a prior encounter. In Experiment 4, recognition memory for faces recognized after cueing was found to be over 90% accurate. This indicates that prompted recognition does not yield repetition priming, even though subjects can remember the faces. A fusion of “face recognition unit” and “episodic record” accounts of the repetition priming effect may be more useful than either theory alone in explaining these results.     

DISSOCIATION OF STORAGE AND REHEARSAL IN VERBAL WORKING MEMORY:

Abstract— Current cognitive models of verbal working memory include two components a phonological store and a rehearsal mechanism that refreshes the contents of this store We present research using positron emission tomography (PET) to provide further evidence for this functional division In Experiment I, subjects performed a variant of Sternberg's (1966) item recognition task Experiment 2 used a continuous memory task with control conditions designed to separate the brain regions underlying storage and rehearsal The results show that independent brain regions mediate storage and rehearsal In Experiment 3, a dual-task procedure supported the assumption that these memory tasks elicited a rehearsal strategy     

Effects of dividing attention during encoding on perceptual priming of unfamiliar visual objects

According to the distractor-selection hypothesis (Mulligan, 2003), dividing attention during encoding reduces perceptual priming when responses to non-critical (i.e., distractor) stimuli are selected frequently and simultaneously with critical stimulus encoding. Because direct support for this hypothesis comes exclusively from studies using familiar word stimuli, the present study tested whether the predictions of the distractor-selection hypothesis extend to perceptual priming of unfamiliar visual objects using the possible/impossible object decision test. Consistent with the distractor-selection hypothesis, Experiments 1 and 2 found no reduction in priming when the non-critical stimuli were presented infrequently and non-synchronously with the critical target stimuli, even though explicit recognition memory was reduced. In Experiment 3, non-critical stimuli were presented frequently and simultaneously during encoding of critical stimuli; however, no decrement in priming was detected, even when encoding time was reduced. These results suggest that priming in the possible/impossible object decision test is relatively immune to reductions in central attention and that not all aspects of the distractor-selection hypothesis generalise to priming of unfamiliar visual objects. Implications for theoretical models of object decision priming are discussed.     

Subjective hierarchies in spatial memory

Two experiments investigated the structure of spatial memories. Subjects learned locations of objects in spatial layouts (Experiment 1) or locations of object names on maps (Experiment 2). Physical and perceptual boundaries were absent in these spatial arrays. Subjects then participated in three tasks: item recognition, in which the variable of interest was spatial priming; free and cued recall; and Euclidean distance estimation. Ordered-tree analysis of individual subjects' recall protocols produced hierarchical trees consistent with regularities in output order. Spatial priming and distance estimations depended on whether pairs of objects appeared in the same subtree or in different subtrees. These findings indicate that spatial memories have a hierarchical component, even when physical and perceptual boundaries are nonexistent. Priming also increased with depth of clustering in ordered trees. This result supports spreading-activation theories of retrieval but provides evidence against several "non-spreading-activation" theories.     

On the differential nature of implicit and explicit memory

In this article, we report two experiments that provide further evidence concerning the differential nature of implicit and explicit memory. In Experiment 1, subjects first undertook a sentenceverification task. While carrying out this task, half of the subjects were also required to carry out a secondary processing task involving tone monitoring. Twenty-four hours later, the subjects’ memory for target items in the sentence-verification task was tested explicitly by means of a recognition task and implicitly by examining the extent to which the items primed fragment completion. Recognition performance was significantly impaired by the imposition of secondary processing demands during the original learning phase. In contrast, fragment completion was completely unaffected by this additional processing, even though substantial priming was observed. In Experiment 2, we examined whether priming in fragment completion is influenced by the nature of repetition during initial learning. Subjects studied a list of target items that were each repeated twice. Halfthe items were repeatedimmediately (lag 0) and halfwere repeated after six intervening items (lag 6). Memory for the itemswas assessed by recognition and by priming in fragment completion. Recognition was affected by lag, with lag 6 items being recognized better than lag 0 items. However, although significant priming was obtained, the extent of this priming was uninfluenced by lag. These data indicate two additional dimensions along which implicit and explicit memory differ and, furthermore, they support recent conceptualizations of processing differences underlying these two forms of memory.     

Effects of environmental support on overt and covert visuospatial rehearsal

People can rehearse to-be-remembered locations either overtly, using eye movements, or covertly, using only shifts of spatial attention. The present study examined whether the effectiveness of these two strategies depends on environmental support for rehearsal. In Experiment 1, when environmental support (i.e., the array of possible locations) was present and participants could engage in overt rehearsal during retention intervals, longer intervals resulted in larger spans, whereas in Experiment 2, when support was present but participants could only engage in covert rehearsal, longer intervals resulted in smaller spans. When environmental support was absent, however, longer retention intervals resulted in smaller memory spans regardless of which rehearsal strategies were available. In Experiment 3, analyses of participants’ eye movements revealed that the presence of support increased participants’ fixations of to-be-remembered target locations more than fixations of non-targets, and that this was associated with better memory performance. Further, although the total time fixating targets increased, individual target fixations were actually briefer. Taken together, the present findings suggest that in the presence of environmental support, overt rehearsal is more effective than covert rehearsal at maintaining to-be-remembered locations in working memory, and that having more time for overt rehearsal can actually increase visuospatial memory spans.     

Spatial and temporal contributions to the structure of spatial memory.

Three experiments investigated the effects of spatial and temporal contiguity in item recognition, location judgment, and distance estimation tasks. Ss learned the locations of object names in spatial arrays, which were divided into 2 regions. The names of locations were presented during map learning so that critical pairs appeared close in space and close in time, close in space but far in time, far in space but close in time, and far in space and far in time. Names primed each other in recognition only when they were neighbors in both space and time. In contrast, the effects of spatial and temporal contiguity in priming in location judgments were additive. Finally, temporal contiguity affected estimates of Euclidean distance when locations were close together, but not when they were far apart.     

Orientation congruency effects for familiar objects: coordinate transformations in object recognition

How do observers recognize objects after spatial transformations? Recent neurocomputational models have proposed that object recognition is based on coordinate transformations that align memory and stimulus representations. If the recognition of a misoriented object is achieved by adjusting a coordinate system (or reference frame), then recognition should be facilitated when the object is preceded by a different object in the same orientation. In the two experiments reported here, two objects were presented in brief masked displays that were in close temporal contiguity; the objects were in either congruent or incongruent picture-plane orientations. Results showed that naming accuracy was higher for congruent than for incongruent orientations. The congruency effect was independent of superordinate category membership (Experiment 1) and was found for objects with different main axes of elongation (Experiment 2). The results indicate congruency effects for common familiar objects even when they have dissimilar shapes. These findings are compatible with models in which object recognition is achieved by an adjustment of a perceptual coordinate system.     

Content and temporal structure of autobiographical knowledge: Remembering twenty-five seasons at the Metropolitan Opera

Three experiments were designed to explore the structure and content of a well-defined subset of very long-term autobiographical memory. In Experiment 1, the author free-recalled in a single session details about the dates and casting of 284 opera performances seen at the Metropolitan Opera over a period of 25 seasons. Recall accuracy was measured by comparing the recall with the programs for each performance. Primacy and recency effects were prominent in recall of both temporal and casting details. Also, recall of performances was superior if the performances were included in the sequential structures of seasons in memory. Experiments 2 and 3 were designed to examine the effect of an opera performance's relative importance (or intensity) and opportunities for rehearsal of an opera performance on the author's free recall of the performance. In Experiment 2, importance/rehearsal opportunity was estimated from nine sources, including recordings, telecasts, tapes, and photograph books. In Experiment 3, the set of opera performances was rated and ranked by four opera experts on the dimension of intensity or importance of each performance. In both experiments, importance/rehearsal opportunity was related to superior recall of casting but not to recall of temporal details. Results suggest that detailed temporal structure in autobiographical memory is lost over time, whereas contents may be updated through various forms of rehearsal.     

Semantic and spatial factors in environmental memory

Reaction time (RT) in simple categorization tasks was predicted to vary as a function of the relatedness among environmental items. Differences in RT were interpreted as reflecting differences in proximity or strength of associations in environmental memory. In Experiment 1, subjects sorted names of familiar local buildings according to which seemed to go together. Hierarchical cluster analysis revealed major clusters whose members were related in function and, within these, smaller clusters of buildings related by spatial proximity. In Experiment 2, subjects responded “Yes” if two items on a trial were both local buildings and “No” if one item was local and one nonlocal. Subjects responded significantly faster to pairs taken from the cluster analysis that were related by both spatial proximity and function than they did to unrelated pairs or pairs related in function only. In Experiment 3, a free-associaton task identified related pairs of spatially proximate, functionally dissimilar environmental items. In Experiment 4, RTs to these pairs did not differ from RTs to pairs of spatially proximate, functionally dissimilar items or from RTs to pairs unrelated functionally and spatially. Spatial proximity and functional similarity together contribute to the organization in memory of buildings in the physical environment.     

The effect of repeated writing on memory

Repeated writing, or rehearsal by writing, is a common memory strategy for the Japanese, especially when learning new logographic characters. The to-be-remembered items are written down not as external prompts, as with reminder notes, but to be memorized in the course of writing them down over and over again. In this study, we investigated whether the strategy was effective, and if so, in which condition. Experiment 1 showed that repeated writing improved memory for graphic designs but not for Chinese characters, words, or syllables. Experiment 2 showed that the effect occurred for both Japanese and American subjects, suggesting that it was not the result of a cultural background associated with a logographic language. Instead, the effect seemed to be accounted for by the encoding specificity of visual-motor information, because repeated writing improved free recall— that included writing—but did not improve recognition (Experiment 3). In Experiment 4, the strategy was applied to learning the Arabic alphabet. Finally, similarities between repeated writing and