Is perceptual salience needed in explanations of the isolation effect?

The isolation effect is a well-known phenomenon that has a well-accepted explanation: An item that is isolated on a list becomes perceptually salient, which leads to extra rehearsal that enhances memory for the isolate. To evaluate this hypothesis, the authors isolated an item near the beginning of a list. Immediately after each item was presented for study, participants judged the likelihood of recalling the item. Although the isolation effect occurred, participants did not judge the isolate as being more memorable than the preceding item, suggesting that the isolate was not salient. In a second experiment, participants rehearsed items aloud. Isolation at the beginning of the list did not produce extra rehearsal. By contrast, isolation in the middle of the list produced extra rehearsal; however, even when the isolate did not receive extra rehearsal, an isolation effect was evident. Thus, salience and extra rehearsal are not necessary for producing an isolation effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using maintenance rehearsal to explore recognition memory.

We examined associative and item recognition using the maintenance rehearsal paradigm. Our intent was to control for mnemonic strategies; to produce a low, graded level of learning; and to provide evidence of the role of attention in long-term memory. An advantage for low-frequency words emerged in both associative and item recognition at very low levels of learning. This early emergence casts doubt on explanations based on the traditional concept of recollection. A comparison of false alarms supports a role for item information or the joint use of cues but not familiarity in producing associative false alarms. We may also have found a way to measure the amount of attention being paid to a to-be-learned item or pair, independently of memory performance on the attended item. This result may be an important step in determining whether coherent theories about the role of attention in long- and short-term memory can be created. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of items in working memory on the deployment of attention and the eyes during visual search.

Paying attention to an object facilitates its storage in working memory. The authors investigate whether the opposite is also true: whether items in working memory influence the deployment of attention. Participants performed a search for a prespecified target while they held another item in working memory. In some trials this memory item was present in the search display as a distractor. Such a distractor has no effect on search time if the search target is in the display. In that case, the item in working memory is unlikely to be selected as a target for an eye movement, and if the eyes do land on it, fixation duration is short. In the absence of the target, however, there is a small but significant effect of the memory item on search time. The authors conclude that the target for visual search has a special status in working memory that allows it to guide attention. Guidance of attention by other items in working memory is much weaker and can be observed only if the search target is not present in the display. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiple processes in the automatic encoding of frequency information.

Conducted 2 studies in which a total of 96 undergraduates were unexpectedly asked to make frequency judgments about words used as distractors during a series of short-term memory tests for digit sequences. Frequency estimates of repeated items were influenced by the interaction of the duration of each vocalization and the number of trials intervening between the 2 occurrences of an item. As the separation between the occurrences increased, the frequency estimates increased only when the items were vocalized for long durations. This same result was not found for mere recognition of items, which was influenced independently by the frequency of presentation and duration of rehearsal. These findings are consistent with a multiple-process hypothesis of frequency representations, according to which distinct frequency traces vary in strength. Results also indicate that distinct representations for repeated events are encoded spontaneously during incidental processing. (French abstract) (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory span: Sources of individual and developmental differences.

Examines 10 possible sources of individual and developmental differences in memory span (rehearsal, grouping, chunking, retrieval strategies, item identification, item ordering, capacity, susceptibility to interference, search rate, and the output buffer) by drawing on existing research. Considerable evidence suggests that the speed with which presented items can be identified is a major source of both individual and developmental differences in span. By contrast, there is no conclusive evidence that the other possibilities examined, including those traditionally associated with span differences (rehearsal, grouping, chunking, and overall information-processing capacity), contribute to variations in span. Speed of item identification differences is discussed in terms of processing efficiency or the capacity needed to activate appropriate perceptual/cognitive units and linguistic programs. (4 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing time for repetitions and the spacing effect.

Two experiments with 98 undergraduates tested L. J. Cuddy and L. L. Jacoby's (see record 1983-04919-001) hypothesis that spacing aids memory for a repeated item to the extent that the S reconstructs the processing of a repeated item due to forgetting of the item's prior presentation. Ss were presented with sequences of words, each of which was accompanied by a short question that required a yes or no answer. Most words were repeated, and several levels of spacing were used. For some Ss, the words were repeated with the same question; for other Ss, different questions accompanied each repetition. Ss were then asked to judge how often each word occurred within the question task. Several levels of spacing and frequency judgments were used as measures of Ss' memory performance. Memory was also measured in terms of probability of a recognition hit and by a recall test that preceded the frequency judgment. Results are generally consistent with Cuddy and Jacoby's hypothesis. A large decline in RT occurred when an item was repeated in the same-question condition, even after a spacing of 40 intervening items, which supports the view that memory for a prior presentation can influence a later presentation of that item. Findings indicate that memory for the prior presentation of an item is less accessible when the repetition varies in form from the prior. (French abstract) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex influence on face recognition memory moderated by presentation duration and reencoding.

Objective: It has been suggested that women have a better face recognition memory than men. Here we analyzed whether this advantage depends on a better encoding or consolidation of information and if the advantage is visible during short-term memory (STM), only, or whether it also remains evident in long-term memory (LTM). Method: We tested short- and long-term face recognition memory in 36 nonclinical participants (19 women). We varied the duration of item presentation (1, 5, and 10 s), the time of testing (immediately after the study phase, 1 hr, and 24 hr later), and the possibility to reencode items (none, immediately after the study phase, after 1 hr). Results: Women showed better overall face recognition memory than men (ηp2 = .15, p     

Induced gamma-band activity during the delay of a visual short-term memory task in humans

It has been hypothesized that visual objects could be represented in the brain by a distributed cell assembly synchronized on an oscillatory mode in the gamma-band (20-80 Hz). If this hypothesis is correct, then oscillatory gamma-band activity should appear in any task requiring the activation of an object representation, and in particular when an object representation is held active in short-term memory: sustained gamma-band activity is thus expected during the delay of a delayed-matching-to-sample task. EEG was recorded while subjects performed such a task. Induced (e.g., appearing with a jitter in latency from one trial to the next) gamma-band activity was observed during the delay. In a control task, in which no memorization was required, this activity disappeared. Furthermore, this gamma-band activity during the rehearsal of the first stimulus representation in short-term memory peaked at both occipitotemporal and frontal electrodes. This topography fits with the idea of a synchronized cortical network centered on prefrontal and ventral visual areas. Activities in the alpha band, in the 15-20 Hz band, and in the averaged evoked potential were also analyzed. The gamma-band activity during the delay can be distinguished from all of these other components of the response, on the basis of either its variations or its topography. It thus seems to be a specific functional component of the response that could correspond to the rehearsal of an object representation in short-term memory.     

Retrieving for rehearsal: An analysis of active rehearsal in children's memory.

Two experiments with 96 2nd graders and 24 6th graders explored the operation of retrieval processes in Ss' active rehearsal strategies. Both experiments used free-recall tasks, in which Ss were given instructions in active rehearsal as well as supports that might facilitate the retrieval operation and thus enhance both rehearsal and recall performance. In Exp I, 2nd and 6th graders were given visual or auditory access to an 18-item stimulus-word list. Results show that, by providing 2nd graders with an opportunity to view previously presented words, rehearsal activity and recall increased substantially, whereas the performance of the 6th graders was not affected. In Exp II, presentation time and visual access to a similar 18-word list were manipulated for 2nd graders. Results show that the provision of extra time for an item enabled Ss to execute a more active rehearsal strategy. Extra time had only minimal effects on recall, except when it was combined with visual access to the items. Findings suggest that retrieval per se is not necessary for the beneficial effects of active rehearsal, if other procedures can be followed to permit the juxtaposition of several items in rehearsal. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contributions to the functional analysis of single-trial free recall.

An extensive body of research generated by the now outmoded dual store model has produced a set of functional principles of single-trial free recall. One principle, termed the ratio rule, describes the properties of the recency effect, while several others based upon laws of rehearsal have been advanced to account for the primacy effect. These principles, which may eventually establish the foundation for a more comprehensive theory of list memory, were tested in three experiments. The first two experiments showed that when rehearsal is eliminated (Experiment 1) or equated (Experiment 2), reliable primacy and recency effects are obtained. The third experiment demonstrated that the effectiveness of rehearsal during list presentation declines monotonically as a function of serial position. These results contrast with the prevailing functional account of both primacy and recency effects and suggest several new lines of inquiry into the subject. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of serial rehearsal training on memory search.

Examined the effects of storage processing on short-term memory search. 32 moderate and 32 high IQ 4th-5th graders were given an S. Sternberg (1966, 1969) recognition memory task. Half of the Ss were trained to use a serial rehearsal strategy during target set storage, and half were given no specific strategy training. The training variable was crossed with rehearsal requirement (overt or covert) so that storage processing could be monitored directly. Dependent measures included S-paced study times, overt rehearsals, and reaction times. Results indicate IQ-related differences in the rate of memory search in the absence of differences in rehearsal during storage. In addition, serial rehearsal training facilitated memory search when rehearsal was covert, particularly for high IQ Ss. The data are discussed with regard to target set storage resulting from a serial rehearsal pattern and to the apparent inverse relationship between IQ and memory-search rate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in temporal and item memory.

Three experiments tested whether the relationship between age differences in temporal and item memory depends on the degree to which the item memory measure relies on memory for context. The authors predicted a stronger relationship of temporal memory to free recall than to recognition memory. Results showed that age differences in temporal memory could be eliminated after controlling for free recall but not recognition memory performance. Under some conditions recognition memory accounted for a significant portion of age-related variance in temporal memory. These results challenge past research that has interpreted age differences in temporal and item memory as independent and suggest that a generalized decline in context memory may underlie reduced performance in older adults on all types of memory tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behaviours that indicate memory: Levels of expression.

Presents examples of research topics that require better criteria as to whether an individual has or has not expressed memory for a particular episode. Some historical reasons as to why this question has not been answered and some contemporary reasons why it is important to answer it now are suggested. Associated implications for fundamental issues of the memory process such as its ontogeny, selectivity, and physiological determinants are discussed. The fundamental observation is that an acquired memory affects relatively subtle behaviors even when having no effect on conventional indices of retention. Examples are drawn from a variety of memory experiments, some using animals and some using humans as Ss. It is concluded that an inevitable step in the study of memory would seem to be more explicit analysis of behavioral reflections of acquired memories, perhaps in terms of different levels at which a memory may be expressed. (French abstract) (65 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of inferior parietal and inferior frontal cortex in working memory.

Verbal working memory involves two major components: a phonological store that holds auditory-verbal information very briefly and an articulatory rehearsal process that allows that information to be refreshed and thus held longer in short-term memory (A. Baddeley, 1996, 2000; A. Baddeley & G. Hitch, 1974). In the current study, the authors tested two groups of patients who were chosen on the basis of their relatively focal lesions in the inferior parietal (IP) cortex or inferior frontal (IF) cortex. Patients were tested on a series of tasks that have been previously shown to tap phonological storage (span, auditory rhyming, and repetition) and articulatory rehearsal (visual rhyming and a 2-back task). As predicted, IP patients were disproportionately impaired on the span, rhyming, and repetition tasks and thus demonstrated a phonological storage deficit. IF patients, however, did not show impairment on these storage tasks but did exhibit impairment on the visual rhyming task, which requires articulatory rehearsal. These findings lend further support to the working memory model and provide evidence of the roles of IP and IF cortex in separable working memory processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Categorization as a preferred memory strategy: Developmental changes during elementary school.

20 2nd, 20 4th, and 20 6th graders (a) judged the relative effectiveness of 4 memory strategies (looking, naming, rehearsing, and categorizing) and (b) studied and recalled sets of stimuli. The order of tasks was counterbalanced within grade. Ss in all grades chose rehearsal and categorization over looking or naming. Second graders in both conditions and 4th graders who did the memory tasks first judged rehearsal and categorization as equally effective. Fourth graders who made strategy judgments first and 6th graders in both conditions significantly preferred categorization over rehearsal. On the memory task, 4th graders who judged strategy effectiveness prior to doing the memory tasks recalled more than those doing the memory task first. There was no difference due to condition for the other 2 grades. Degree of strategic awareness was related to recall only for children who made the strategy judgment prior to doing the memory tasks. Findings illustrate developmental changes in awareness of the relative benefits of categorization over rehearsal during elementary school and suggest that performance on a memory task may be affected by the degree to which appropriate metamemorial awareness is "activated." (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Life-span differences in memory integration as a function of processing time.

K. Pezdek (see record 1981-03016-001) reported life-span differences in integration of semantically related pictures and sentences in memory; 6th-grade and high school Ss spontaneously integrated information across modalities, but 3rd graders and adults over 65 did not integrate this information. The present study extends these findings and tests the hypothesis that the 8-sec presentation rate in the previous study was not sufficient to allow the young children and older adults to perform integration processes in memory. Although 3rd graders and older adults (63–78 yrs) did not integrate pictures and sentences that were presented individually at an 8-sec rate, when the presentation rate was increased to 15 sec per item, cross-modality integration resulted. This result is interpreted to mean that the slower presentation rate was necessary for these Ss to actively rehearse different items together, and that this rehearsal strategy is necessary for integration of information in memory. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rehearsal training and developmental differences in memory.

To examine the relation between age-related changes in the activity of rehearsal and corresponding changes in recall, 96 2nd and 6th graders were trained in a variety of rehearsal techniques in an overt rehearsal free recall task. Consistent with previous work, developmental differences in the number of items rehearsed together were observed when Ss were given no particular training. These rehearsal differences were related to corresponding changes in the recall of initially presented items. The recall of 2nd-grade noninstructed Ss was similar to that of Ss instructed to rehearse only 1 or 2 items together; the serial position curves of these groups indicated no primacy effects. In contrast, the recall of Ss who rehearsed several items together was similar to that of noninstructed 6th graders, with significant primacy effects being observed in these conditions. Second-grade Ss were able to adopt this active rehearsal strategy and to continue using it on a transfer task. The facilitative effects of active rehearsal were mediated neither by priority in recall given to early list items nor by enhanced subjective organization. Results are discussed in terms of multistore models of memory. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What causes the isolation effect?

Events that are incongruent with their prevailing context are usually very well remembered. This fact often is described as the distinctiveness effect in memory, an effect that has served as explanation not only of memory phenomena but also of various other phenomena, including social judgment. The core laboratory paradigm for studying distinctiveness in memory research has long been the isolation paradigm. This paradigm, sometimes attributed to H. von Restorff (1933), yields better memory for an item categorically isolated from surrounding items than for the surrounding items and a proper control item. The authors offer an interpretation of the isolation effect based on the analysis of the processing of similarities and differences among the items. Two experiments provide evidence for this interpretation. The results are discussed in the context of current theories of distinctiveness effects in memory. An appeal is made for a different conceptualization of distinctiveness effects, one that treats distinctiveness as a discriminative process in memory that requires processing of both similarities and differences among items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Source memory in the absence of successful cued recall.

Five experiments were conducted to address the question of whether source information could be accessed in the absence of being able to recall an item. The authors used a paired-associate learning paradigm in which cue-target word pairs were studied, and target recall was requested in the presence of the cue. When target recall failed, participants were asked to make a source judgment of whether a man or woman spoke the unrecalled item. In 3 of the 5 experiments, source accuracy was at or very close to chance. By contrast, if cue-target pairs were studied multiple times or participants knew in advance of learning that a predictive judgment would be required, then predictive source accuracy was well above chance. These data are suggestive that context information may not play a very large role in metacognitive judgments such as feeling-of-knowing ratings or putting one into a tip-of-the-tongue state without strong and specific encoding procedures. These same results also highlight the important role that item memory plays in retrieving information about the context in which an item was experienced. (PsycINFO Database Record (c) 2010 APA, all rights reserved)