The emergence of item-specific encoding effects in between-subjects designs: perceptual interference and multiple recall tests

The perceptual-interference effect occurs when interference with word perception (by backward masking) enhances later memory for the word. In terms of the item-specific-relational framework (Hunt & McDaniel, 1993), this effect is similar to other manipulations that enhance item-specific encoding (such as the generation effect). One similarity is that item-specific effects typically do not arise in between-subjects designs. However, the present experiment demonstrates that a between-subjects perceptual-interference effect emerges over multiple recall tests. Furthermore, perceptual interference produces both more intertest gains (indexing enhanced item-specific processing) and more intertest losses (indexing disrupted relational encoding) compared with the intact (control) condition. Finally, delaying the mask to a point at which it no longer interferes with perception (266 msec) eliminates both the perceptual-interference recall advantage and the increase in intertest gains. This condition still produces more intertest losses, however. Together, these results imply that a delayed mask disrupts relational encoding but produces no item-specific enhancement, dissociating the two effects of the perceptual-interference manipulation.     

Perceptual interference at encoding enhances recall for high- but not low-imageability words

Interfering with stimulus perception during encoding can improve later explicit memory (the perceptual-interference effect). The compensatory-processing hypothesis attributes the perceptualinterference effect to enhanced processing of higher level (nonvisual) information during perception. Recent research indicates that the semantic dimension of imageability is one type of higher level information that plays a role in word perception. To the extent that semantic representations play a more important role in the perception of high- than for low-imageability words, the compensatoryprocessing hypothesis predicts a larger perceptual-interference effect for high- than for lowimageability words. Two experiments confirm this prediction. A robust effect of perceptual interference was found for high- but not for low-imageability words.     

Effects of item-specific and relational information on hypermnesic recall

The role of encoding conditions in producing hypermnesia (increased recall over successive trials) was examined by manipulating the availability of item-specific and relational information at encoding. Our findings demonstrate that encodings providing item-specific information (e.g., elaborative encodings) produce hypermnesia by facilitating the recovery of new items over trials, whereas encodings providing relational information (e.g., organizational encodings) produce hypermnesia by protecting against the loss of previously recalled items. Thus, the effects of encodings on hypermnesia may be understood by considering the type of trace information they make available.     

Modality independence of order coding in working memory: Evidence from cross-modal order interference at recall

Working memory researchers do not agree on whether order in serial recall is encoded by dedicated modality-specific systems or by a more general modality-independent system. Although previous research supports the existence of autonomous modality-specific systems, it has been shown that serial recognition memory is prone to cross-modal order interference by concurrent tasks. The present study used a serial recall task, which was performed in a single-task condition and in a dual-task condition with an embedded memory task in the retention interval. The modality of the serial task was either verbal or visuospatial, and the embedded tasks were in the other modality and required either serial or item recall. Care was taken to avoid modality overlaps during presentation and recall. In Experiment 1, visuospatial but not verbal serial recall was more impaired when the embedded task was an order than when it was an item task. Using a more difficult verbal serial recall task, verbal serial recall was also more impaired by another order recall task in Experiment 2. These findings are consistent with the hypothesis of modality-independent order coding. The implications for views on short-term recall and the multicomponent view of working memory are discussed.     

The effect of instruction with relational and item-specific elaborative strategies on young children's organization and free recall

One hundred and sixty second-grade children were assigned on the basis of a free recall pretest to four instruction conditions and were given a series of lists of pictures for free recall. For three groups, the instructions were directed at encoding either (a) list organizational information, (b) item-specific semantic information, or (c) organizational and individual item information, while the fourth group constituted a “No-training” control with standard free recall instructions. The subjects received either related or unrelated lists during the training phase and related or unrelated lists during two post-tests, immediately following and 1 week after training. For both types of lists, instructions emphasizing list organization were more effective than those emphasizing item-specific elaboration. Subjects given individual item elaborative instructions showed levels of recall which were comparable to those of the control subjects. While the combined effect of organizational and individual item processing did not exceed the performance produced by organizational instructions alone, the degree of generalization was greater for subjects processing both kinds of information, especially when subjects received related lists during training.     

Beyond category sorting and pleasantness rating: Inducing relational and item-specific processing

In most studies of relational and item-specific processing, category sorting and pleasantness rating have been the main procedures used to induce these two types of processing. Because the two types of processing have been studied in a wide range of memory phenomena (Hunt & McDaniel, 1993), it is strange that other tasks have not been proposed and tested. The present experiment demonstrates that equivalent results can be obtained with three relational processing tasks (category sorting, narrative construction, and relational imagery) and equivalent results with three itemspecific processing tasks (pleasantness ratings, familiarity ratings, and single imagery).     

Part-list cuing with and without item-specific probes: The role of encoding

Part-list cuing—the detrimental effect of the presentation of a subset of studied items on recall of the remaining noncue items—was examined in three different study conditions and in the presence and absence of the noncues’ initial letters serving as item-specific probes. With a single study trial, part-list cuing was observed both with and without item-specific probes. By contrast, when participants received two study-test cycles or interrelated list items to a common story, part-list cues were found to be detrimental only in the absence of item-specific probes, but not in their presence. These results indicate that the role of item-specific probes in part-list cuing depends on encoding. The findings are consistent with a recent two-mechanism account of part-list cuing (Bäuml &; Aslan, 2006), according to which two different mechanisms mediate the effect in different encoding situations.     

Total retrieval time and hypermnesia: Investigating the benefits of multiple recall tests

Hypermnesia is an increase in recall over repeated tests. A core issue is the role of repeated testing, per se, versus total retrieval time. Prior research implies an equivalence between multiple recall tests and a single test of equal total duration, but theoretical analyses indicate otherwise. Three experiments investigated this issue using various study materials (unrelated word lists, related word lists, and a short story). In the first experimental session, the study phase was followed by a series of short recall tests or by a single, long test of equal total duration. Two days later, participants took a final recall test. The multiple and single test conditions produced equivalent performance in the first session, but the multiple test group exhibited less forgetting and fewer item losses in the final test. In a fourth experiment, using a brief delay (15 min) between the recall sessions, the multiple recall condition produced greater hypermnesia as well as fewer item losses. In addition, final recall was significantly higher in the multiple than in the single test condition in three of the four experiments. Thus, single and repeated recall tests of equal total duration are not functionally equivalent, but rather produce differences observable in subsequent recall tests.     

Memory in pregnancy and post‐partum: Item specific and relational encoding processes in recall and recognition

It has been recently proposed that pregnant women would perform memory tasks by focusing more on item‐specific processes and less on relational processing, compared to post‐partum women (Mickes, Wixted, Shapiro & Scarff, 2009 ). The present cross‐sectional study tested this hypothesis by directly manipulating the type of encoding employed in the study phase. Pregnant, post‐partum and control women either rated the pleasantness of word meaning (which induced item‐specific elaboration) or named the semantic category to which they belonged (which induced relational elaboration). Memory for the encoded words was later tested in free recall (which emphasizes relational processing) and in recognition (which emphasizes item‐specific processing). In line with Mickes et al.'s ( 2009 ) conclusions, pregnant women in the item‐specific condition performed worse than post‐partum women in the relational condition in free recall, but not in recognition. However, compared to the other two groups, pregnant women also exhibited lower recognition accuracy in the item‐specific condition. Overall, these results confirm that pregnant women rely on relational encoding less than post‐partum women, but additionally suggest that the former group might use item‐specific processes less efficiently than post‐partum and control women.     

Motor resources in peripersonal space are intrinsic to spatial encoding: Evidence from motor interference

The aim of this study was to explore the role of motor resources in peripersonal space encoding: are they intrinsic to spatial processes or due to action potentiality of objects? To answer this question, we disentangled the effects of motor resources on object manipulability and spatial processing in peripersonal and extrapersonal spaces. Participants had to localize manipulable and non-manipulable 3-D stimuli presented within peripersonal or extrapersonal spaces of an immersive virtual reality scenario. To assess the contribution of motor resources to the spatial task a motor interference paradigm was used. In Experiment 1, localization judgments were provided with the left hand while the right dominant arm could be free or blocked. Results showed that participants were faster and more accurate in localizing both manipulable and non-manipulable stimuli in peripersonal space with their arms free. On the other hand, in extrapersonal space there was no significant effect of motor interference. Experiment 2 replicated these results by using alternatively both hands to give the response and controlling the possible effect of the orientation of object handles. Overall, the pattern of results suggests that the encoding of peripersonal space involves motor processes per se, and not because of the presence of manipulable stimuli. It is argued that this motor grounding reflects the adaptive need of anticipating what may happen near the body and preparing to react in time.     

Item-specific and relational encoding effects in children's recall and recognition memory for words

This study tests the hypothesis that children's deficiency in encoding itemspecific and relational information in episodic events contributes to age differences in recall and recognition. In two experiments, grade school children and college adults were presented with word triplets varying in categorical relatedness. The processing of the item-specific and relational information in the triplets was independently manipulated. Experiment 1 assessed cued recall, and Experiment 2 assessed recognition of both the central target and incidental contextual members of each triplet. The results showed that the processing manipulations had independent and different effects on recall and recognition, on memory for the members of the different kinds of triplets, on the use of the retrieval cues, and on memory for target and incidental words. Developmental differences were found in both recall and recognition, and of both target and incidental words, that varied with triplet type and the processing manipulations and that were attributable to differences in the encoding of item-specific and relational information in the triplets. The discussion contrasts alternative accounts of children's encoding deficiency, and suggests that the distinction between automatic, age-invariant, and strategic age-sensitive encoding processes needs to be redrawn.     

The subordination effect: Evidence from self-paced reading and recall

Engelkamp and Rummer (2002) demonstrated that auditorily presented subordinate causal sentences are better retained than coordinate sentences. This subordination effect was explained by suggesting that subordinate sentences are merged more easily in memory than coordinate sentences. The present paper enlarges Engelkamp and Rummer's findings with respect to three aspects. First, it demonstrates that the subordination effect can only be found if a verbatim but not a content related recall score is used. Second, using self-paced reading, it demonstrates a processing advantage for subordinate sentences. This reading time advantage was only observed if the subordinate clause preceded the matrix clause. Third, it excludes an alternative explanation of the subordination effect which attributes memory differences to the fact that the critical causal conjunction word was presented earlier in subordinate than in coordinate sentences. In sum, our findings suggest a direct contribution of syntactic information to sentence regeneration.     

Inhibitory tagging in inhibition of return: Evidence from flanker interference with multiple distractor features

Fuentes, Vivas, and Humphreys (1999) proposed a distinction betweeninhibition of return (IOR) and inhibitory processing taking place at a location subject to IOR. This latter mechanism,inhibitory tagging (IT), would act at a late level of processing related to response selection. In the present study, we examined whether IT was applied only to the target-relevant properties of the stimuli (e.g., to its color) or whether it was applied to other features of the stimulus as well (e.g., to its shape). Both when the task was to respond to the target’s color (Experiment 1) as well as when it was to respond to the target’s shape (Experiment 2), there was evidence of IT (reversal of the typical flanker effect at the cued location, relative to the uncued location) only to task-relevant features of the target. These findings suggest that IT is a central process of control constrained by task demands and current goals.     

Perceptual impulsions and unfamiliar solids: Evidence from a drawing task

Previous work (Dziurawiec & Derȩgowski, 1992) has shown that children's distorted drawings of animal models may be explained by the child's tendency to depict typical contours, the outlines of the surfaces which undergo pronounced change. The present paper investigates whether the typical contours notion can be extended to purely geometric solids. Results from a drawing task by children aged nine and eleven years, using unfamiliar models of varying complexity, indicate that the tendency to draw in perspective increases with the increase in figure complexity for both age groups, but younger children show a greater reliance on typical contours than older children. Recasting the data from previous drawing experiments (Bartel, 1928/1958; Cox, 1986) further confirms the utility of the typical contours approach. Finally, the advantages of such an approach over that of canonicity (cf. Palmer, Rosch & Chase, 1981) for the representation of solids are elaborated.     

Judging the contact-times of multiple objects: Evidence for asymmetric interference

The accuracy of time-to-contact (TTC) judgments for single approaching objects is well researched, however, close to nothing is known about our ability to make simultaneous TTC judgments for two or more objects. Such complex judgments are required in many everyday situations, for instance when crossing a multi-lane street or when engaged in multi-player ball games. We used a prediction-motion paradigm in which participants simultaneously estimated the absolute TTC of two objects, and compared the performance to a standard single-object condition. Results showed that the order of arrival of the two objects determined the accuracy of the TTC estimates: Estimation of the first-arriving object was unaffected by the added complexity compared to the one-object condition, whereas the TTC of the second-arriving object was systematically overestimated. This result has broad implications for complex everyday situations. We suggest that it is akin to effects observed in experiments on the psychological refractory period (PRP) and that the proactive interference of the first-arriving object indicates a bottleneck or capacity sharing at the central stage.     

Perceptual simulation in conceptual combination: Evidence from property generation

In three experiments, participants received nouns or noun phrases for objects and verbally generated their properties (“feature listing”). Several sources of evidence indicated that participants constructed perceptual simulations to generate properties for the noun phrases during conceptual combination. First, the production of object properties for noun phrases depended on occlusion, with unoccluded properties being generated more often than occluded properties. Because a perceptual variable affected conceptual combination, perceptual simulations appeared central to combining the concepts for modifiers and head nouns. Second, neutral participants produced the same distributions of properties as participants instructed to describe images, suggesting that the conceptual representations used by neutral participants were similar to the mental images used by imagery participants. Furthermore, the property distributions for neutral and imagery participants differed from those for participants instructed to produce word associations. Third, participants produced large amounts of information about background situations associated with the object cues, suggesting that the simulations used to generate properties were situated. The experiments ruled out alternative explanations that simulation effects occur only for familiar noun phrases associated with perceptual memories and that rules associated with modifiers produce occlusion effects. A process model of the property generation task grounded in simulation mechanisms is presented. The possibility of integrating the simulation account of conceptual combination with traditional accounts and well-established findings is explored.     

Delayed stimulus control: recall for single and relational stimuli.

In a discrete-trial symbolic matching-to-sample procedure, pigeons' left-key responses were reinforced following presentation of one center-key sample, and right-key responses were reinforced following presentation of another. Recallability was measured by the difference between log ratios of left to right responses following each sample. In Experiment 1, samples were successively presented same or different wavelengths in the relational discrimination, or individual wavelengths in the single discrimination. The rate at which recallability decreased with increasing delay since sample presentation was the same for single and relational discriminations, but the initial level of performance differed, indicating that the relational discrimination was more difficult. In Experiment 2, recall functions for easy and difficult discriminations between individual wavelengths also differed in levels of initial performance but not in rate of decrement of recallability over time. Recall for stimuli differing in complexity may therefore reflect differences in discrimination difficulty.