Retrieval speeds context fluctuation: Why semantic generation enhances later learning but hinders prior learning

In recent work, retrieval has been shown to enhance memory for events following that retrieval. In this set of experiments, we examined the effects of interleaved semantic retrieval on both previous and future learning within a multilist learning paradigm. Interleaved retrieval led to enhanced memory for lists learned following retrieval. In contrast, memory was impaired for lists learned prior to retrieval (Experiment 1). These results are consistent with recent work in multilist learning, directed forgetting, and list-before-last retrieval, all of which indicate a crucial role for retrieval in enhancing mental list segregation. This pattern of results follows clearly from a theoretical perspective in which retrieval drives internal contextual change and in which contextual overlap between study and test promotes better memory. Consistent with that perspective, a 15-min delay before the final test eliminated both effects (Experiment 2). Experiment 2 replicated the results of Experiment 1 with materials and assessments more appropriate for educational settings: Interleaved semantic retrieval led learners to be more able to answer questions correctly about texts studied after a retrieval event but less able to do so for texts studied earlier.     

Are forward and backward recall the same? A dual-task study of digit recall

There is some debate surrounding the cognitive resources underlying backward digit recall. Some researchers consider it to differ from forward digit recall due to the involvement of executive control, while others suggest that backward recall involves visuospatial resources. Five experiments therefore investigated the role of executive-attentional and visuospatial resources in both forward and backward digit recall. In the first, participants completed visuospatial 0-back and 2-back tasks during the encoding of information to be remembered. The concurrent tasks did not differentially disrupt performance on backward digit recall, relative to forward digit recall. Experiment 2 shifted concurrent load to the recall phase instead and, in this case, revealed a larger effect of both tasks on backward recall, relative to forwards recall, suggesting that backward recall may draw on additional resources during the recall phase and that these resources are visuospatial in nature. Experiments 3 and 4 then further investigated the role of visual processes in forward and backward recall using dynamic visual noise (DVN). In Experiment 3, DVN was presented during encoding of information to be remembered and had no effect upon performance. However, in Experiment 4, it was presented during the recall phase, and the results provided evidence of a role for visual imagery in backward digit recall. These results were replicated in Experiment 5, in which the same list length was used for forward and backward recall tasks. The findings are discussed in terms of both theoretical and practical implications.     

Working memory for relations among objects

Across many areas of study in cognition, the capacity of working memory (WM) is widely agreed to be roughly three to five items: three to five objects (i.e., bound collections of object features) in the literature on visual WM or three to five role bindings (i.e., objects in specific relational roles) in the literature on memory and reasoning. Three experiments investigated the capacity of observers’ WM for the spatial relations among objects in a visual display, and the results suggest that the “items” in WM are neither simply objects nor simply role bindings. The results of Experiment 1 are most consistent with a model that treats an “item” in visual WM as an object, along with the roles of all its relations to one other object. Experiment 2 compared observers’ WM for object size with their memory for relative size and provided evidence that observers compute and store objects’ relations per se (rather than just absolute size) in WM. Experiment 3 tested and confirmed several more nuanced predictions of the model supported by Experiment 1. Together, these findings suggest that objects are stored in visual WM in pairs (along with all the relations between the objects in a pair) and that, from the perspective of WM, a given object in one pair is not the same “item” as that same object in a different pair.     

The mental wormhole: Internal attention shifts without regard for distance

Attention operates perceptually on items in the environment, and internally on objects in visuospatial working memory. In the present study, we investigated whether spatial and temporal constraints affecting endogenous perceptual attention extend to internal attention. A retro-cue paradigm in which a cue is presented beyond the range of iconic memory and after stimulus encoding was used to manipulate shifts of internal attention. Participants?? memories were tested for colored circles (Experiments 1, 2, 3a, 4) or for novel shapes (Experiment 3b) and their locations within an array. In these experiments, the time to shift internal attention (Experiments 1 and 3) and the eccentricity of encoded objects (Experiments 2?C4) were manipulated. Our data showed that, unlike endogenous perceptual attention, internal shifts of attention are not modulated by stimulus eccentricity. Across several timing parameters and stimuli, we found that shifts of internal attention require a minimum quantal amount of time regardless of the object eccentricity at encoding. Our findings are consistent with the view that internal attention operates on objects whose spatial information is represented in relative terms. Although endogenous perceptual attention abides by the laws of space and time, internal attention can shift across spatial representations without regard for physical distance.     

Interference of spoken word recognition through phonological priming from visual objects and printed words

Three cross-modal priming experiments examined the influence of preexposure to pictures and printed words on the speed of spoken word recognition. Targets for auditory lexical decision were spoken Dutch words and nonwords, presented in isolation (Experiments 1 and 2) or after a short phrase (Experiment 3). Auditory stimuli were preceded by primes, which were pictures (Experiments 1 and 3) or those pictures’ printed names (Experiment 2). Prime–target pairs were phonologically onset related (e.g., pijl–pijn, arrow–pain), were from the same semantic category (e.g., pijl–zwaard, arrow–sword), or were unrelated on both dimensions. Phonological interference and semantic facilitation were observed in all experiments. Priming magnitude was similar for pictures and printed words and did not vary with picture viewing time or number of pictures in the display (either one or four). These effects arose even though participants were not explicitly instructed to name the pictures and where strategic naming would interfere with lexical decision making. This suggests that, by default, processing of related pictures and printed words influences how quickly we recognize spoken words.     

Integration of visuospatial information encoded from different viewpoints

Two experiments investigated whether separate sets of objects viewed in the same environment but from different views were encoded as a single integrated representation or maintained as distinct representations. Participants viewed two circular layouts of objects that were placed around them in a round (Experiment 1) or a square (Experiment 2) room and were later tested on perspective-taking trials requiring retrieval of either one layout (within-layout trials) or both layouts (between-layout trials). Results from Experiment 1 indicated that participants did not integrate the two layouts into a single representation. Imagined perspective taking was more efficient on within- than on between-layout trials. Furthermore, performance for within-layout trials was best from the perspective that each layout was studied. Results from Experiment 2 indicated that the stable environmental reference frame provided by the square room caused many, but not all, participants to integrate all locations within a common representation. Participants who integrated performed equally well for within-layout and between-layout judgments and also represented both layouts using a common reference frame. Overall, these findings highlight the flexibility of organizing information in spatial memory.     

Investigating the speed–accuracy trade-off: Better use deadlines or response signals?

Deadlines (DLs) and response signals (RSs) are two well-established techniques for investigating speed–accuracy trade-offs (SATs). Methodological differences imply, however, that corresponding data do not necessarily reflect equivalent processes. Specifically, the DL procedure grants knowledge about trial-specific time demands and requires responses before a prespecified period has elapsed. In contrast, RS intervals often vary unpredictably between trials, and responses must be given after an explicit signal. Here, we investigated the effects of these differences in a flanker task. While all conditions yielded robust SAT functions, a right-shift of the curves pointed to reduced performance in RS conditions (Experiment 1, blocked; Experiments 2 and 3, randomized), as compared with DL conditions (Experiments 1–3, blocked), indicating that the detection of the RS imposes additional task demands. Moreover, the flanker effect vanished at long intervals in RS settings, suggesting that stimulus-related effects are absorbed in a slack when decisions are completed prior to the signal. In turn, effects of a flat (Experiment 2) versus a performance-contingent payment (Experiment 3) indicated that susceptibility to response strategies is higher in the DL than in the RS method. Finally, the RS procedure led to a broad range of slow responses and high accuracies, whereas DL conditions resulted in smaller variations in the upper data range (Experiments 1 and 2); with performance-contingent payment (Experiment 3), though, data ranges became similar. Together, the results uncover characteristic procedure-related effects and should help in selection of the appropriate technique.     

The effects of interleaving versus blocking on foreign language pronunciation learning

Many studies have shown that students learn better when they are given repeated exposures to different concepts in a way that is shuffled or interleaved, rather than blocked (e.g., Rohrer Educational Psychology Review, 24, 355–367, 2012). The present study explored the effects of interleaving versus blocking on learning French pronunciations. Native English speakers learned several French words that conformed to specific pronunciation rules (e.g., the long “o” sound formed by the letter combination “eau,” as in bateau), and these rules were presented either in blocked fashion (bateau, carreau, fardeau . . . mouton, genou, verrou . . . tandis, verglas, admis) or in interleaved fashion (bateau, mouton, tandis, carreau, genou, verglas . . .). Blocking versus interleaving was manipulated within subjects (Experiments 1–3) or between subjects (Experiment 4), and participants’ pronunciation proficiency was later tested through multiple-choice tests (Experiments 1, 2, and 4) or a recall test (Experiment 3). In all experiments, blocking benefited the learning of pronunciations more than did interleaving, and this was true whether participants learned only 4 words per rule (Experiments 1–3) or 15 words per rule (Experiment 4). Theoretical implications of these findings are discussed.     

A motor similarity effect in object memory

In line with theories of embodied cognition (e.g., Versace et al. European Journal of Cognitive Psychology, 21, 522–560, 2009), several studies have suggested that the motor system used to interact with objects in our environment is involved in object recognition (e.g., Helbig, Graf, & Kiefer Experimental Brain Research, 174, 221-228, 2006). However, the role of the motor system in immediate memory for objects is more controversial. The objective of the present study was to investigate the role of the motor system in object memory by manipulating the similarity between the actions associated to series of objects to be retained in memory. In Experiment 1, we showed that lists of objects associated to dissimilar actions were better recalled than lists associated to similar actions. We then showed that this effect was abolished when participants were required to perform a concurrent motor suppression task (Experiment 2) and when the objects to be memorized were unmanipulable (Experiment 3). The motor similarity effect provides evidence for the role of motor affordances in object memory.     

Coarse guidance by numerosity in visual search

In five experiments, we examined whether the number of items can guide visual focal attention. Observers searched for the target area with the largest (or smallest) number of dots (squares in Experiment 4 and “checkerboards” in Experiment 5) among distractor areas with a smaller (or larger) number of dots. Results of Experiments 1 and 2 show that search efficiency is determined by target to distractor dot ratios. In searches where target items contained more dots than did distractor items, ratios over 1.5:1 yielded efficient search. Searches for targets where target items contained fewer dots than distractor items were harder. Here, ratios needed to be lower than 1:2 to yield efficient search. When the areas of the dots and of the squares containing them were fixed, as they were in Experiments 1 and 2, dot density and total dot area increased as dot number increased. Experiment 3 removed the density and area cues by allowing dot size and total dot area to vary. This produced a marked decline in search performance. Efficient search now required ratios of above 3:1 or below 1:3. By using more realistic and isoluminant stimuli, Experiments 4 and 5 show that guidance by numerosity is fragile. As is found with other features that guide focal attention (e.g., color, orientation, size), the numerosity differences that are able to guide attention by bottom-up signals are much coarser than the differences that can be detected in attended stimuli.     

An electrophysiological study of the object-based correspondence effect: Is the effect triggered by an intended grasping action?

We examined Goslin, Dixon, Fischer, Cangelosi, and Ellis’s (Psychological Science 23:152–157, 2012) claim that the object-based correspondence effect (i.e., faster keypress responses when the orientation of an object’s graspable part corresponds with the response location than when it does not) is the result of object-based attention (vision–action binding). In Experiment 1, participants determined the category of a centrally located object (kitchen utensil vs. tool), as in Goslin et al.’s study. The handle orientation (left vs. right) did or did not correspond with the response location (left vs. right). We found no correspondence effect on the response times (RTs) for either category. The effect was also not evident in the P1 and N1 components of the event-related potentials, which are thought to reflect the allocation of early visual attention. This finding was replicated in Experiment 2 for centrally located objects, even when the object was presented 45 times (33 more times than in Exp. 1). Critically, the correspondence effects on RTs, P1s, and N1s emerged only when the object was presented peripherally, so that the object handle was clearly located to the left or right of fixation. Experiment 3 provided further evidence that the effect was observed only for the base-centered objects, in which the handle was clearly positioned to the left or right of center. These findings contradict those of Goslin et al. and provide no evidence that an intended grasping action modulates visual attention. Instead, the findings support the spatial-coding account of the object-based correspondence effect.     

Exploiting illusory effects to disclose similarities in numerical and luminance processing

Recent studies have suggested that numerical and physical magnitudes are similarly processed by a generalized magnitude system. The present study investigates the number?Cluminance interaction, taking advantage of illusory effects in a cued line bisection task with numerical or nonnumerical flankers and varying levels of luminance. The results showed that both dimensions influenced bisection performance. Whereas numbers (Experiment 1) induced a systematic shift of the subjective midpoint toward the larger digit, luminance (Experiment 2) modulated the bisection performance toward the darker flanker. By combining these two illusions (Experiments 3 and 4), the two dimensions interfered with each other. This pattern of results suggests overlapping representations for physical and numerical magnitudes and highlights the value of illusory effects in cognitive research.     

Moral kinematics: The role of physical factors in moral judgments

Harmful events often have a strong physical component??for instance, car accidents, plane crashes, fist fights, and military interventions. Yet there has been very little systematic work on the degree to which physical factors influence our moral judgments about harm. Since physical factors are related to our perception of causality, they should also influence our subsequent moral judgments. In three experiments, we tested this prediction, focusing in particular on the roles of motion and contact. In Experiment 1, we used abstract video stimuli and found that intervening on a harmful object was judged as being less bad than intervening directly on the victim, and that setting an object in motion was judged as being worse than redirecting an already moving object. Experiment 2 showed that participants were sensitive not only to the presence or absence of motion and contact, but also to the magnitudes and frequencies associated with these dimensions. Experiment 3 extended the findings from Experiment 1 to verbally presented moral dilemmas. These results suggest that domain-general processes play a larger role in moral cognition than is currently assumed.     

Top-down constraint on recognition memory

Can recognition memory be constrained “at the front end,” such that people are more likely to retrieve information about studying a recognition-test probe from a specified target source than they are to retrieve such information about a probe from a nontarget source? We adapted a procedure developed by Jacoby, Shimizu, Daniels, and Rhodes (Psychonomic Bulletin & Review 12:852–857, 2005) to address this question. Experiment 1 yielded evidence of source-constrained retrieval, but that pattern was not significant in Experiments 2, 3, and 4 (nor in several unpublished pilot experiments). In Experiment 5, in which items from the two studied sources were perceptibly different, a pattern consistent with front-end constraint of recognition emerged, but this constraint was likely exercised via visual attention rather than memory. Experiment 6 replicated both the absence of a significant constrained-retrieval pattern when the sources did not differ perceptibly (as in Exps. 2, 3 and 4) and the presence of that pattern when they did differ perceptibly (as in Exp. 5). Our results suggest that people can easily constrain recognition when items from the to-be-recognized source differ perceptibly from items from other sources (presumably via visual attention), but that it is difficult to constrain retrieval solely on the basis of source memory.     

Focused attention improves working memory: implications for flexible-resource and discrete-capacity models

Performance in working memory (WM) tasks depends on the capacity for storing objects and on the allocation of attention to these objects. Here, we explored how capacity models need to be augmented to account for the benefit of focusing attention on the target of recall. Participants encoded six colored disks (Experiment 1) or a set of one to eight colored disks (Experiment 2) and were cued to recall the color of a target on a color wheel. In the no-delay condition, the recall-cue was presented after a 1,000-ms retention interval, and participants could report the retrieved color immediately. In the delay condition, the recall-cue was presented at the same time as in the no-delay condition, but the opportunity to report the color was delayed. During this delay, participants could focus attention exclusively on the target. Responses deviated less from the target’s color in the delay than in the no-delay condition. Mixture modeling assigned this benefit to a reduction in guessing (Experiments 1 and 2) and transposition errors (Experiment 2). We tested several computational models implementing flexible or discrete capacity allocation, aiming to explain both the effect of set size, reflecting the limited capacity of WM, and the effect of delay, reflecting the role of attention to WM representations. Both models fit the data better when a spatially graded source of transposition error is added to its assumptions. The benefits of focusing attention could be explained by allocating to this object a higher proportion of the capacity to represent color.     

Concept formation and categorization of complex,asymmetric, and impossible figures

Impossible figures are striking examples of inconsistencies between global and local perceptual structures, in which the overall spatial configuration of the depicted image does not yield a coherent three-dimensional object. In order to investigate whether structural “impossibility” is an important perceptual property of depicted objects, we used a category formation task in which subjects were asked to divide pictures of shapes into groups that seemed most natural to them. Category formation is usually unidimensional, such that sorting is dominated by a single perceptual property, so this task can serve as a measure of which dimensions are most salient. In Experiment 1, subjects received sets of 12 line drawings consisting of six possible and six impossible objects. Very few subjects grouped the figures by impossibility on the first try, and only half did so after multiple attempts at sorting. In Experiment 2, we investigated other global properties of figures: symmetry and complexity. Subjects readily sorted objects by complexity, but seldom by symmetry. In Experiment 3, subjects were asked to draw each of the figures before sorting them, which had only a minimal effect on categorization. Finally, in Experiment 4, subjects were explicitly instructed to divide the shapes by symmetry or impossibility. Performance on this task was perfect for symmetry, but not for impossibility. Although global properties of figures seem extremely important to our perception, the results suggest that some of these cues are not immediately obvious or salient for most observers.     

Infants’ discrimination of crossed and uncrossed horizontal disparity

In a series of preferential-looking experiments, infants 5 to 6 months of age were tested for their responsiveness to crossed and uncrossed horizontal disparity. In Experiments 1 and 2, infants were presented with dynamic random dot stereograms displaying a square target defined by either a 0.5° crossed or a 0.5° uncrossed horizontal disparity and a square control target defined by a 0.5° vertical disparity. In Experiment 3, infants were presented with the crossed and the uncrossed horizontal disparity targets used in Experiments 1 and 2. According to the results, the participants looked more often at the crossed (Experiment 1), as well as the uncrossed (Experiment 2), horizontal disparity targets than at the vertical disparity target. These results suggest that the infants were sensitive to both crossed and uncrossed horizontal disparity information. Moreover, the participants exhibited a natural visual preference for the crossed over the uncrossed horizontal disparity (Experiment 3). Since prior research established natural looking and reaching preferences for the (apparently) nearer of two objects, this finding is consistent with the hypothesis that the infants were able to extract the depth relations specified by crossed (near) and uncrossed (far) horizontal disparity.     

Memory as discrimination: What distraction reveals

Recalling information involves the process of discriminating between relevant and irrelevant information stored in memory. Not infrequently, the relevant information needs to be selected from among a series of related possibilities. This is likely to be particularly problematic when the irrelevant possibilities not only are temporally or contextually appropriate, but also overlap semantically with the target or targets. Here, we investigate the extent to which purely perceptual features that discriminate between irrelevant and target material can be used to overcome the negative impact of contextual and semantic relatedness. Adopting a distraction paradigm, it is demonstrated that when distractors are interleaved with targets presented either visually (Experiment 1) or auditorily (Experiment 2), a within-modality semantic distraction effect occurs; semantically related distractors impact upon recall more than do unrelated distractors. In the semantically related condition, the number of intrusions in recall is reduced, while the number of correctly recalled targets is simultaneously increased by the presence of perceptual cues to relevance (color features in Experiment 1 or speaker’s gender in Experiment 2). However, as is demonstrated in Experiment 3, even presenting semantically related distractors in a language and a sensory modality (spoken Welsh) distinct from that of the targets (visual English) is insufficient to eliminate false recalls completely or to restore correct recall to levels seen with unrelated distractors . Together, the study shows how semantic and nonsemantic discriminability shape patterns of both erroneous and correct recall.     

Time-compressed spoken word primes crossmodally enhance processing of semantically congruent visual targets

Findings from three experiments support the conclusion that auditory primes facilitate the processing of related targets. In Experiments 1 and 2, we employed a crossmodal Stroop color identification task with auditory color words (as primes) and visual color patches (as targets). Responses were faster for congruent priming, in comparison to neutral or incongruent priming. This effect also emerged for different levels of time compression of the auditory primes (to 30 % and 10 % of the original length; i.e., 120 and 40 ms) and turned out to be even more pronounced under high-perceptual-load conditions (Exps. 1 and 2). In Experiment 3, target-present or -absent decisions for brief target displays had to be made, thereby ruling out response-priming processes as a cause of the congruency effects. Nevertheless, target detection (d') was increased by congruent primes (30 % compression) in comparison to incongruent or neutral primes. Our results suggest semantic object-based auditory–visual interactions, which rapidly increase the denoted target object’s salience. This would apply, in particular, to complex visual scenes.     

A severe capacity limit in the consolidation of orientation information into visual short-term memory

Previous research has suggested that two color patches can be consolidated into visual short-term memory (VSTM) via an unlimited parallel process. Here we examined whether the same unlimited-capacity parallel process occurs for two oriented grating patches. Participants viewed two gratings that were presented briefly and masked. In blocks of trials, the gratings were presented either simultaneously or sequentially. In Experiments 1 and 2, the presentation of the stimuli was followed by a location cue that indicated the grating on which to base one’s response. In Experiment 1, participants responded whether the target grating was oriented clockwise or counterclockwise with respect to vertical. In Experiment 2, participants indicated whether the target grating was oriented along one of the cardinal directions (vertical or horizontal) or was obliquely oriented. Finally, in Experiment 3, the location cue was replaced with a third grating that appeared at fixation, and participants indicated whether either of the two test gratings matched this probe. Despite the fact that these responses required fairly coarse coding of the orientation information, across all methods of responding we found superior performance for sequential over simultaneous presentations. These findings suggest that the consolidation of oriented gratings into VSTM is severely limited in capacity and differs from the consolidation of color information.