Encoding specificity and unidirectional associates in cued recall

The first of two experiments confirmed the earlier findings of Humphreys and Galbraith (1975), that under silent-study encoding instructions, words assessed as strong elicitors of target words are effective extralist retrieval cues, whereas words assessed as weak elicitors are not. In the second experiment, predictions from the encoding specificity principle were confirmed with respect to the effectiveness of forward and backward retrieval cues in recall. Contrary to the conclusions of Humphreys and Galbraith, forward and backward unidirectional associates were equally effective as retrieval cues, provided subjects engaged in associative encoding (generated associations to the target words) at storage.     

Recognition of multiple-item probes

In the present study, we contrasted models in whichfamiliarity orstrength is the sole basis for recognition judgments (e.g., Gillund & Shiffrin, 1984) with models incorporating retrieval of specific information in a recall-like process (e.g., Humphreys, 1976, 1978; Humphreys & Bain, 1984). We also examined the possibility that an item’s “strength” is determined in part by the match between the verbal encoding contexts at study and at test. In two experiments, study items were presented in triplets. In Experiment 1 recognition was tested with all possible combinations of one-, two-, or three-item targets and distractors; in addition, three different decision criteria were employed in different lists. Experiment 2 included cued recognition among other test conditions. Recognition performance did not increase as more cues were added to the probe, a finding that is inconsistent with Humphreys’s model and other models of that type. Both studies were well fit by a version of the Search of Associative Memory model for recognition (Gillund & Shiffrin, 1984).     

New evidence for the zoom lens model using the RSVP technique

A main prediction from the zoom lens model for visual attention is that performance is an inverse function of the size of the attended area. The “attention shift paradigm” developed by Sperling and Reeves (1980) was adapted here to study predictions from the zoom lens model. In two experiments two lists of items were simultaneously presented using the rapid serial visual presentation technique. Subjects were to report the first item he/she was able to identify in the series that did not include the target (the letter T) after he/she saw the target. In one condition, subjects knew in which list the target would appear; in another condition, they did not have this knowledge, having to attend to both positions in order to detect the target. The zoom lens model predicts an interaction between this variable and the distance separating the two positions where the lists are presented. In both experiments, this interaction was observed. The results are also discussed as a solution to the apparently contradictory results with regard to the analog movement model.     

Immediate judgments of learning are insensitive to implicit interference effects at retrieval

We conducted three experiments to determine whether metamemory predictions at encoding, immediate judgments of learning (IJOLs) are sensitive to implicit interference effects that will occur at retrieval. Implicit interference was manipulated by varying the association set size of the cue (Experiments 1 and 2) or the target (Experiment 3). The typical finding is that memory is worse for large-set-size cues and targets, but only when the target is studied alone and later prompted with a related cue (extralist). When the pairs are studied together (intralist), recall is the same regardless of set size; set size effects are eliminated. Metamemory predictions at retrieval, such as delayed JOLs (DJOLs) and feeling-of-knowing (FOK) judgments accurately reflect implicit interference effects (e.g., Eakin & Hertzog, 2006. In all three experiments, we found that DJOLs and FOKs accurately predicted set size effects on retrieval but that IJOLs did not. The findings provide further evidence that metamemory predictions are inferred from information other than direct access to the state of the memory trace, as well as indicate that inferences are based on different sources depending on when in the memory process predictions are made.     

Priming in a free association task as a function of association directionality

Two experiments investigated priming in free association, a conceptual implicit memory task. The stimuli consisted of bidirectionally associated word pairs (e.g., BEACH-SAND) and unidirectionally associated word pairs that have no association from the target response back to the stimulus cue (e.g., BONE-DOG). In the study phase, target words (e.g., SAND, DOG) were presented in an incidental learning task. In the test phase, participants generated an associate to the stimulus cues (e.g., BEACH, BONE). In both experiments, priming was obtained for targets (e.g., SAND) that had an association back to the cue, but not for targets (e.g., DOG) for which such a backward association was absent. These results are problematic for theoretical accounts that attribute priming in free association to the strengthening of target responses. It is argued that priming in free association depends on the strengthening of cue-target associations.     

Reversing the phonological similarity effect

The phonological similarity effect--poor retention of order for lists of similar-sounding items--is a benchmark finding in the short-term memory literature. In our first two experiments, we show that the effect actually reverses following relatively brief periods of distraction, yielding better order retention for similar than for dissimilar lists, provided that different items are used on every trial. In Experiment 3, the same items were used on every trial and similar lists produced poorer performance across all three retention intervals. The results are interpreted from a general discrimination framework: Items are viewed as occupying positions in a multidimensional space defined by list and within-list dimensions.     

The correlation between cue differentiation and associative recall

Two experiments were conducted to correlate performance on a test of cue differentiation with cued recall. In one experiment, subjects were given 2, 5, 8, or 12 study repetitions on verbal items consisting of three-word cues and single-word targets. The cues had varying numbers and patterns of identical elements. Cues were tested for differentiability and for their ability to produce target recall. In the second experiment, study repetitions on the same type of lists were followed by the two tests after the second, fourth, and final study repetitions. With a few exceptions, the frequency of occurrence of items that both were successfully differentiated and produced correct recall did not deviate significantly from predictions based on the assumption of independence of the two measures.     

多目标追踪任务中不同运动方式非目标的抑制机制

采用多目标追踪范式结合点探测技术的方法, 考察视觉系统对不同运动方式(静止和规则运动)非目标的抑制机制。实验一将部分非目标设置为静止, 考察静止非目标的抑制机制; 实验二将部分非目标设置为规则运动, 以提高任务难度, 考察规则运动非目标的抑制机制。结果发现: (1) 实验一中静止非目标受到抑制, 抑制量与运动非目标没有差异; (2) 实验二中规则运动非目标受到抑制, 抑制量显著小于随机运动非目标; (3)综合两实验发现, 随着任务难度的提高, 只有随机运动非目标的抑制量显著增加, 而静止非目标与规则运动非目标的抑制量差异不显著。最后, 就视觉系统对不同运动方式非目标的抑制机制进行了讨论。     

Does training under consistent mapping conditions lead to automatic attention attraction to targets in search tasks?

Schneider and Shiffrin (1977) proposed that training under consistent stimulus-response mapping (CM) leads to automatic target detection in search tasks. Other theories, such as Treisman and Gelade's (1980) feature integration theory, consider target-distractor discriminability as the main determinant of search performance. The first two experiments pit these two principles against each other. The results show that CM training is neither necessary nor sufficient to achieve optimal search performance. Two other experiments examine whether CM trained targets, presented as distractors in unattended display locations, attract attention away from current targets. The results are again found to vary with target-distractor similarity. Overall, the present study strongly suggests that CM training does not invariably lead to automatic attention attraction in search tasks.     

Nature of the representation for picture-recognition memory

When distracting pictures are randomly selected from the same pool of pictures as the target pictures, performance with large numbers of pictures (1,000) is much poorer than has previously been reported. Further, performance drops quite substantially after 1 wk., a finding that differs from the conclusion that picture memory is relatively stable over time. Under conditions where the distractors were selected to reduce similarity between targets and distracting pictures, performance approximated levels previously reported in the literature. The results of the experiments seem to demand some type of categorization model of picture-recognition memory.     

Direction of association between targets in a RSVP task influences priming at very short but not long SOAs

When two targets are presented using rapid serial visual presentation (RSVP) and the interval between the targets is 200–500 ms, detection or identification of the second target is impaired. This impairment in second target report is known as the attentional blink (AB). This study sought to examine the impact of the direction of target association on priming during an AB task using very short and long SOAs. Two experiments were conducted using dual-stream RSVP tasks and targets that either shared an associative relationship or were unrelated to one another. The direction of association between the targets was also varied so that associatively related targets were presented in the forward (strongest association from target 1 to target 2) or backward directions of association (strongest association from target 2 to target 1). In Experiment 1 very short SOAs between targets (27–213 ms) were used. Priming was evident at the same SOAs for both targets presented in the backward direction of association. However, for targets presented in the forward direction of association, priming occurred for target 1 and target 2 at different SOAs. Experiment 2 used longer SOAs between targets (107 to 535 ms) and it was determined that while direction of association between the targets did not affect priming, there was a larger priming effect for target 2 than for target 1. The results of the two experiments indicate that direction of association between targets influences priming in RSVP tasks that use very short but not long SOAs. The results are discussed in relation to the two-stage response competition model of Potter et al. (J Exp Psychol Hum Percept Perform 28:1149–1162, 2002).     

The types of stimuli loaded in memory can modulate its effects on visual search

The effects of memory load in visual search (VS) have shown a diversity of results from the absence through beneficial and detrimental effects of a concurrent memory load in VS performance. One of the hypotheses intended to explain the heterogeneity of results follows the idea proposed by certain models in the context of VS that the contents of working memory (WM) can modulate the attentional processes involved in VS (Desimone & Duncan, 1995; Duncan & Humphreys, 1989). In four experiments, we manipulated the similarity of information maintained in WM and those materials playing the role of target and distractors in the VS task. The results showed a beneficial effect in the first two experiments, where the materials in WM matched the target in VS. However, when they matched the distractors in the attentional task there is no effect in the slope of the search function. Present results strengthen those theories supporting that visual working memory is fractionated to allow for maintenance of items not essential to the attentional task (Downing & Dodds, 2004).     

Phonological encoding in the attentional blink paradigm

The attentional blink refers to a deficit in reporting a second target that follows a first target within a few hundred milliseconds, when both targets occur in a sequence of distractors shown serially at rates of about 10 items per second. In four experiments, phonological similarity of post-Target 1 distractors impaired dual target report within the interval in which the attentional blink occurs. Similarity of letter targets had a smaller, less reliable effect on performance. Phonological similarity of letter distractors did not affect single target identification (Experiment 3), but it continued to impair dual target report (Experiment 5), even when the targets belonged to a different category—namely, digits. The results demonstrated that, not only targets, but also distractors are encoded phonologically, despite the fact that distractors are irrelevant and never have to be reported.     

Reversing presentation order of semantically related words reverses memory

In the Deese-Roediger-McDermott paradigm, words (e.g., sour, candy, sugar,…) related to one critical word (e.g., sweet) typically are encoded in descending order of their association with the critical word. When recognition is tested, memory is greater for related words than for critical words, as predicted by extant memory models. Surprisingly, however, memory is not greater for unrelated words (presented in other encoding lists) than for related words, in contrast with predictions from these same models. In two experiments, we tested whether intralist presentation order is responsible for the unexplained results. Word lists were studied in standard or reversed order (ascending order of association to critical words). Subsequent recognition for related words was high when lists were presented in the standard order but very low when lists were presented in reverse. Results indicate that presentation order affects related-word false alarms, providing important new constraints for memory models.     

Processing of words presented simultaneously to eye and ear

The simultaneous processing of auditorily and visually presented messages was examined in three experiments. Subjects searched lists of words for a target word while processing auditorily presented information. Across conditions, subjects searched for (a) target words in a list of words presented auditorily, (b) the same target words in lists presented visually, (c) a member of a taxonomic category in a visually presented list, and (d) a rhyme in a list of words presented visually. The level of processing of a simultaneous auditory message varied across experiments. In experiment 1, subjects shadowed lists of digits. In Experiment 2, subjects reported the antonym of each word in a list. In Experiment 3, subjects named the taxonomic category of each word in a list. In all three experiments, subject had high detection rates for target words presented visually and for category targets but low detection rates for target words presented auditorily and for rhyme targets. These results suggest that processing the semantic properties, but not the acoustic properties, of words presented to the visual modality is independent of simultaneous processing in the auditory modality. Implication for models of selective attention are discussed.     

Memory as discrimination: a challenge to the encoding-retrieval match principle

Four experiments contrasted the predictions of a general encoding-retrieval match hypothesis with those of a view claiming that the distinctiveness of the cue-target relationship is the causal factor in retrieval. In Experiments 1, 2, and 4 participants learned the relationships between 4 targets and trios of cues; in Experiment 3 there were 3 targets, each associated with a pair of cues. A learning phase was followed by a cued-recognition task where the correct target had to be identified based on 1 or more of the cues. The main performance measurement was response time. Learning was designed to lead to high accuracy so effects could be attributed to retrieval efficiency rather than to variations in encoding. The nature of the cues and targets was varied across experiments. The critical factor was whether each cue was uniquely associated with the to-be-recalled target. All experiments orthogonally manipulated (a) how discriminative-or uniquely associated with a target-each cue was and (b) the degree of overlap between the cues present during learning and those present at retrieval. The novel finding reported here is that increasing the encoding-retrieval match can hinder performance if the increase simultaneously reduces how well cues predict a target-that is, a cue's diagnostic value. Encoding-retrieval match was not the factor that determined the effectiveness of retrieval. Our findings suggest that increasing the encoding-retrieval match can lead to no change, an increase, or a decrease in retrieval performance.     

Effects of word frequency on individual-item and serial order retention: Tests of the order-encoding view

The order-encoding view of the word frequency effect proposes that low-frequency (LF) items attract more attention to the encoding of individual-item information than do high-frequency (HF) items, but at the expense of order encoding (DeLosh & McDaniel, 1996). When combined with the assumption that free recall of unrelated words is organized according to their original order of presentation, this view explains the finding that HF words are better recalled than LF words in pure lists but that, in mixed lists, recall is better for LF words. The present study confirmed that in mixed lists, order memory becomes equivalent for HF and LF words and that the predicted pattern of order memory and recall holds fo r incidental order-encoding conditions, for longerlists than those used inprevious experiments, and for lists with minimal interitem associativity. Moreover, recall from HF lists declined, but recall from LF lists improved, in related-word lists, relative to unrelated-word lists, reversing the usual pure-list free recall advantage for HF words. These results were uniquely predicted by the order-encoding account and favor this view over accessibility, interitem association, and cuing effectiveness explanations of the word frequency effect.     

Disruption of short-term memory by distractor speech: Does content matter?

Four experiments replicate the finding that auditory distractors that are lexically identical to the visual target items dramatically increase the irrelevant-speech effect on serial recall. This effect was previously attributed to interference of incompatible order cues. The present results suggest that a different interpretation of this effect is required. Experiment 2 replicates the order congruence effect observed by Hughes and Jones (2005), but shows that this effect is most likely due to an attenuation of interference that is caused by strategic attention shifts to the nominally irrelevant material. Experiments 3 and 4 show that the between-stream similarity effect generalizes to a condition in which the distractor items were drawn from the same category as the targets, but were not identical to them. By showing that nonacoustic distractor features can increase interference in serial recall of lists of supposedly “meaningless” items such as digits or consonants, the results are most consistent with models that postulate an integration of short-term and long-term memory such as the embedded-processes model and the feature model and are inconsistent with classical structural accounts of memory.     

Resource demands of object tracking and differential allocation of the resource

The attentional processes for tracking moving objects may be largely hemisphere-specific. Indeed, in our first two experiments the maximum object speed (speed limit) for tracking targets in one visual hemifield (left or right) was not significantly affected by a requirement to track additional targets in the other hemifield. When the additional targets instead occupied the same hemifield as the original targets, the speed limit was reduced. At slow target speeds, however, adding a second target to the same hemifield had little effect. At high target speeds, the cost of adding a same-hemifield second target was approximately as large as would occur if observers could only track one of the targets. This shows that performance with a fast-moving target is very sensitive to the amount of resource allocated. In a third experiment, we investigated whether the resources for tracking can be distributed unequally between two targets. The speed limit for a given target was higher if the second target was slow rather than fast, suggesting that more resource was allocated to the faster of the two targets. This finding was statistically significant only for targets presented in the same hemifield, consistent with the theory of independent resources in the two hemifields. Some limited evidence was also found for resource sharing across hemifields, suggesting that attentional tracking resources may not be entirely hemifield-specific. Together, these experiments indicate that the largely hemisphere-specific tracking resource can be differentially allocated to faster targets.     

Encoding and retrieval processes in the memory for conceptually distinctive events

Memory for conceptually isolated (distinctive) words was investigated in two experiments. In Experiment 1, recognition of distinctive targets was compared with recognition of targets from homogeneous lists and with recognition of background information. Distinctive targets were better recognized than the same words presented in homogeneous lists. No effects of distinctiveness on the recognition accuracy of background items were observed. These results fail to support the hypothesis that distinctive information receives extra resources during encoding at the expense of surrounding background information. In Experiment 2 the effects of distinctiveness on recall were evaluated. Distinctive targets were more likely to be recalled than targets from homogeneous lists. However, unlike the effects found in recognition, background items were more poorly recalled from lists containing distinctive targets than from homogeneous lists. Organizational processes in recall were also evaluated. There was greater subjective organization for target and background items from lists containing distinctive targets than from lists containing nondistinctive targets. These results were discussed in terms of encoding and retrieval explanations of the effects of distinctiveness.