The company a word keeps: The role of neighbourhood density in verbal short-term memory.

Psycholinguistic information plays an important role in verbal short-term memory (vSTM). One such linguistic feature is neighbourhood density (ND)-the number of words that can be derived from a given word by changing a single phoneme or single letter-with vSTM performance typically better when word sequences are from dense rather than sparse neighbourhoods. This effect has been attributed to higher levels of supportive activation among dense neighbourhood words. Generally, it has been assumed that lexical variables influence item memory but not order memory, and we show that the typical vSTM advantage for dense neighbourhood words in serial recall is eliminated when using serial recognition. However, we also show that the usual effect of ND is reversed-for both serial recall and serial recognition-when using a subset of those same words. The findings call into question the way in which ND has been incorporated into accounts of vSTM that invoke mutual support from long-term representations on either encoding or retrieval.

Learning through clamor: The allocation and perception of study time in noise.

Memory tasks involve a degree of judgment and strategic decision-making, based upon the perceived benefits of particular learning, maintenance and recall strategies. The consequences of these metacognitive judgments for memory have been amply documented under experimental conditions that require participants to focus upon a task in the absence of distractors. Eight experiments consider the impact of less benign environmental conditions-specifically, the presence of distracting speech-upon the metacognitive aspects of memory. Distraction reliably disrupted free recall and, as indicated by judgments of learning, participants were aware of this effect. However, because participants did not adjust study time in compensation, the distraction effect was exaggerated relative to experimenter-imposed presentation rates. This finding appears to be the consequence of distraction-induced disruption of time perception at encoding, rather than any deliberate strategy. The results highlight the need to consider the impact of more challenging environments on metacognition generally. (PsycINFO Database Record

Memory as embodiment: The case of modality and serial short-term memory.

Classical explanations for the modality effect-superior short-term serial recall of auditory compared to visual sequences-typically recur to privileged processing of information derived from auditory sources. Here we critically appraise such accounts, and re-evaluate the nature of the canonical empirical phenomena that have motivated them. Three experiments show that the standard account of modality in memory is untenable, since auditory superiority in recency is often accompanied by visual superiority in mid-list serial positions. We explain this simultaneous auditory and visual superiority by reference to the way in which perceptual objects are formed in the two modalities and how those objects are mapped to speech motor forms to support sequence maintenance and reproduction. Specifically, stronger obligatory object formation operating in the standard auditory form of sequence presentation compared to that for visual sequences leads both to enhanced addressability of information at the object boundaries and reduced addressability for that in the interior. Because standard visual presentation does not lead to such object formation, such sequences do not show the boundary advantage observed for auditory presentation, but neither do they suffer loss of addressability associated with object information, thereby affording more ready mapping of that information into a rehearsal cohort to support recall. We show that a range of factors that impede this perceptual-motor mapping eliminate visual superiority while leaving auditory superiority unaffected. We make a general case for viewing short-term memory as an embodied, perceptual-motor process.

The Item versus the Object in Memory: On the Implausibility of Overwriting As a Mechanism for Forgetting in Short-Term Memory.

The nature of forgetting in short-term memory remains a disputed topic, with much debate focussed upon whether decay plays a fundamental role (Berman et al., 2009; Altmann and Schunn, 2012; Barrouillet et al., 2012; Neath and Brown, 2012; Oberauer and Lewandowsky, 2013; Ricker et al., 2014) but much less focus on other plausible mechanisms. One such mechanism of long-standing in auditory memory is overwriting (e.g., Crowder and Morton, 1969) in which some aspects of a representation are "overwritten" and rendered inaccessible by the subsequent presentation of a further item. Here, we review the evidence for different forms of overwriting (at the feature and item levels) and examine the plausibility of this mechanism both as a form of auditory memory and when viewed in the context of a larger hearing, speech and language understanding system.

Negative priming in free recall reconsidered.

Negative priming in free recall is the finding of impaired memory performance when previously ignored auditory distracters become targets of encoding and retrieval. This negative priming has been attributed to an aftereffect of deploying inhibitory mechanisms that serve to suppress auditory distraction and minimize interference with learning and retrieval of task-relevant information. In 6 experiments, we tested the inhibitory account of the effect of negative priming in free recall against alternative accounts. We found that ignoring auditory distracters is neither sufficient nor necessary to produce the effect of negative priming in free recall. Instead, the effect is more readily accounted for by a buildup of proactive interference occurring whenever 2 successively presented lists of words are drawn from the same semantic category. (PsycINFO Database Record

Erroneous and veridical recall are not two sides of the same coin: Evidence from semantic distraction in free recall.

Two experiments examined the extent to which erroneous recall blocks veridical recall using, as a vehicle for study, the disruptive impact of distractors that are semantically similar to a list of words presented for free recall. Instructing participants to avoid erroneous recall of to-be-ignored spoken distractors attenuated their recall but this did not influence the disruptive effect of those distractors on veridical recall (Experiment 1). Using an externalized output-editing procedure-whereby participants recalled all items that came to mind and identified those that were erroneous-the usual between-sequences semantic similarity effect on erroneous and veridical recall was replicated but the relationship between the rate of erroneous and veridical recall was weak (Experiment 2). The results suggest that forgetting is not due to veridical recall being blocked by similar events.

A matter of emphasis: Linguistic stress habits modulate serial recall.

Models of short-term memory for sequential information rely on item-level, feature-based descriptions to account for errors in serial recall. Transposition errors within alternating similar/dissimilar letter sequences derive from interactions between overlapping features. However, in two experiments, we demonstrated that the characteristics of the sequence are what determine the fates of items, rather than the properties ascribed to the items themselves. Performance in alternating sequences is determined by the way that the sequences themselves induce particular prosodic rehearsal patterns, and not by the nature of the items per se. In a serial recall task, the shapes of the canonical "saw-tooth" serial position curves and transposition error probabilities at successive input-output distances were modulated by subvocal rehearsal strategies, despite all item-based parameters being held constant. We replicated this finding using nonalternating lists, thus demonstrating that transpositions are substantially influenced by prosodic features-such as stress-that emerge during subvocal rehearsal.

Distraction control processes in free recall: benefits and costs to performance.

How is semantic memory influenced by individual differences under conditions of distraction? This question was addressed by observing how participants recalled visual target words--drawn from a single category--while ignoring spoken distractor words that were members of either the same or a different (single) category. Working memory capacity (WMC) was related to disruption only with synchronous, not asynchronous, presentation, and distraction was greater when the words were presented synchronously. Subsequent experiments found greater negative priming of distractors among individuals with higher WMC, but this may be dependent on targets and distractors being comparable category exemplars. With less dominant category members as distractors, target recall was impaired--relative to control--only among individuals with low WMC. The results highlight the role of cognitive control resources in target-distractor selection and the individual-specific cost implications of such cognitive control.

Boundaries of semantic distraction: dominance and lexicality act at retrieval.

Three experiments investigated memory for semantic information with the goal of determining boundary conditions for the manifestation of semantic auditory distraction. Irrelevant speech disrupted the free recall of semantic category- exemplars to an equal degree regardless of whether the speech coincided with presentation or test phases of the task (Experiment 1), and this occurred regardless of whether it comprised random words or coherent sentences (Experiment 2). The effects of background speech were greater when the irrelevant speech was semantically related to the to-be-remembered material, but only when the irrelevant words were high in output dominance (Experiment 3). The implications of these findings in relation to the processing of task material and the processing of background speech are discussed.

'What's in a name?' 'No more than when it's mine own'. Evidence from auditory oddball distraction.

Research of the distractor value of hearing the own name has shown that this self-referring stimulus captures attention in an involuntary fashion and create distraction. The behavioral studies are few and the outcomes are not always clear cut. In this study the distraction by own name compared to a control name was investigated by using a cross-modal oddball task in two experiments. In the first experiment, thirty-nine participants were conducting a computerized categorization task while exposed to, to-be ignored own and matched control names (controlling for familiarity, gender and number of syllables) as unexpected auditory deviant stimulus (12.5% trials for each name category) and a sine wave tone as a standard stimulus (75% of the trials). In the second experiment, another group of thirty-nine participants completed the same task but with the additional deviant stimulus of an irrelevant word added (10% trials for each deviant type and 70% trials with the standard stimulus). Results showed deviant distraction by exposure to both the irrelevant word, own and the control name compared to the standard tone but no differences were found showing that the own name captured attention and distracted the participants more than an irrelevant word or a control name. The results elucidate the role of the own name as a potent auditory distractor and possible limitations with its theoretical significance for general theories of attention are discussed.

The effects of distraction on metacognition and metacognition on distraction: evidence from recognition memory.

The effects of auditory distraction in memory tasks have, to date, been examined with procedures that minimize participants' control over their own memory processes. Surprisingly little attention has been paid to metacognitive control factors which might affect memory performance. In this study, we investigate the effects of auditory distraction on metacognitive control of memory, examining the effects of auditory distraction in recognition tasks utilizing the metacognitive framework of Koriat and Goldsmith (1996), to determine whether strategic regulation of memory accuracy is impacted by auditory distraction. Results replicated previous findings in showing that auditory distraction impairs memory performance in tasks minimizing participants' metacognitive control (forced-report test). However, the results revealed also that when metacognitive control is allowed (free-report tests), auditory distraction impacts upon a range of metacognitive indices. In the present study, auditory distraction undermined accuracy of metacognitive monitoring (resolution), reduced confidence in responses provided and, correspondingly, increased participants' propensity to withhold responses in free-report recognition. Crucially, changes in metacognitive processes were related to impairment in free-report recognition performance, as the use of the "don't know" option under distraction led to a reduction in the number of correct responses volunteered in free-report tests. Overall, the present results show how auditory distraction exerts its influence on memory performance via both memory and metamemory processes.

Language and short-term memory: the role of perceptual-motor affordance.

The advantage for real words over nonwords in serial recall--the lexicality effect--is typically attributed to support for item-level phonology, either via redintegration, whereby partially degraded short-term traces are "cleaned up" via support from long-term representations of the phonological material or via the more robust temporary activation of long-term lexical phonological knowledge that derives from its combination with established lexical and semantic levels of representation. The much smaller effect of lexicality in serial recognition, where the items are re-presented in the recognition cue, is attributed either to the minimal role for redintegration from long-term memory or to the minimal role for item memory itself in such retrieval conditions. We show that the reduced lexicality effect in serial recognition is not a function of the retrieval conditions, but rather because previous demonstrations have used auditory presentation, and we demonstrate a robust lexicality effect for visual serial recognition in a setting where auditory presentation produces no such effect. Furthermore, this effect is abolished under conditions of articulatory suppression. We argue that linguistic knowledge affects the readiness with which verbal material is segmentally recoded via speech motor processes that support rehearsal and therefore affects tasks that involve recoding. On the other hand, auditory perceptual organization affords sequence matching in the absence of such a requirement for segmental recoding and therefore does not show such effects of linguistic knowledge.

Modalities of memory: is reading lips like hearing voices?

Functional similarities in verbal memory performance across presentation modalities (written, heard, lipread) are often taken to point to a common underlying representational form upon which the modalities converge. We show here instead that the pattern of performance depends critically on presentation modality and different mechanisms give rise to superficially similar effects across modalities. Lipread recency is underpinned by different mechanisms to auditory recency, and while the effect of an auditory suffix on an auditory list is due to the perceptual grouping of the suffix with the list, the corresponding effect with lipread speech is due to misidentification of the lexical content of the lipread suffix. Further, while a lipread suffix does not disrupt auditory recency, an auditory suffix does disrupt recency for lipread lists. However, this effect is due to attentional capture ensuing from the presentation of an unexpected auditory event, and is evident both with verbal and nonverbal auditory suffixes. These findings add to a growing body of evidence that short-term verbal memory performance is determined by modality-specific perceptual and motor processes, rather than by the storage and manipulation of phonological representations.

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.

Auditory distraction eliminates retrieval induced forgetting: implications for the processing of unattended sound.

The Retrieval-Induced Forgetting (RIF) paradigm includes three phases: (a) study/encoding of category exemplars, (b) practicing retrieval of a sub-set of those category exemplars, and (c) recall of all exemplars. At the final recall phase, recall of items that belong to the same categories as those items that undergo retrieval practice, but that did not undergo retrieval practice themselves, is impaired. The received view is that this is because retrieval of target category-exemplars (e.g., "Tiger" in the category Four-legged animal) requires inhibition of nontarget category-exemplars (e.g., "Dog" and "Lion") that compete for retrieval. Here, we used the RIF paradigm to investigate whether ignoring auditory items during the retrieval-practice phase modulates the inhibitory process. In two experiments, RIF was present when retrieval practice was conducted in quiet and when it was conducted in the presence of spoken words that were drawn from a different category to that from which the targets for retrieval practice were selected. In contrast, RIF was abolished when words that were either identical to, or merely semantically related to, the retrieval-practice words were presented as background speech. The results suggest that the act of ignoring speech can reduce inhibition of the non-practiced category-exemplars, thereby eliminating RIF, but only when the spoken words are competitors for retrieval (i.e., belong to the same semantic category as the to-be-retrieved items).

Auditory distraction compromises random generation. Falling back into old habits?

Auditory distraction of random generation--a quintessentially executive control task--was explored in three experiments. Random number generation was impaired by the mere presence of irrelevant auditory sequences that comprise digits, but not letters, and then only if the digits were heard in a canonical order (1, 2, 3 … or 3, 2, 1 …), not in random order (Experiments 1 and 2). Random letter generation was impaired by irrelevant letters heard in alphabetical order (a, b, c …) and reversed alphabetical order (i, h, g …), but not by numbers in canonical order or letters in random order (Experiment 3). Attempting to ignore canonical sequences--with items that are members of the same category as the to-be-generated items--reduced the randomness of the generated sequence, by decreasing the tendency to change the direction of the produced sequence for random number generation, and by increasing resampling of responses for random letter generation. Like other selective attention tasks, the cost of distraction to random generation appears to stem from preventing habitual responses assuming the control of action.

Cognitive control of auditory distraction: impact of task difficulty, foreknowledge, and working memory capacity supports duplex-mechanism account.

The influence of top-down cognitive control on 2 putatively distinct forms of distraction was investigated. Attentional capture by a task-irrelevant auditory deviation (e.g., a female-spoken token following a sequence of male-spoken tokens)-as indexed by its disruption of a visually presented recall task-was abolished when focal-task engagement was promoted either by increasing the difficulty of encoding the visual to-be-remembered stimuli (by reducing their perceptual discriminability; Experiments 1 and 2) or by providing foreknowledge of an imminent deviation (Experiment 2). In contrast, distraction from continuously changing auditory stimuli ("changing-state effect") was not modulated by task-difficulty or foreknowledge (Experiment 3). We also confirmed that individual differences in working memory capacity--typically associated with maintaining task-engagement in the face of distraction--predict the magnitude of the deviation effect, but not the changing-state effect. This convergence of experimental and psychometric data strongly supports a duplex-mechanism account of auditory distraction: Auditory attentional capture (deviation effect) is open to top-down cognitive control, whereas auditory distraction caused by direct conflict between the sound and focal-task processing (changing-state effect) is relatively immune to such control.

Inhibitory control in memory: evidence for negative priming in free recall.

Cognitive control mechanisms--such as inhibition--decrease the likelihood that goal-directed activity is ceded to irrelevant events. Here, we use the action of auditory distraction to show how retrieval from episodic long-term memory is affected by competitor inhibition. Typically, a sequence of to-be-ignored spoken distracters drawn from the same semantic category as a list of visually presented to-be-recalled items impairs free recall performance. In line with competitor inhibition theory (Anderson, 2003), free recall was worse for items on a probe trial if they were a repeat of distracter items presented during the previous, prime, trial (Experiment 1). This effect was produced only when the distracters were dominant members of the same category as the to-be-recalled items on the prime. For prime trials in which distracters were low-dominant members of the to-be-remembered item category or were unrelated to that category--and hence not strong competitors for retrieval--positive priming was found (Experiments 2 and 3). These results are discussed in terms of inhibitory approaches to negative priming and memory retrieval.

Retrieval from memory: vulnerable or inviolable?

We show that retrieval from semantic memory is vulnerable even to the mere presence of speech. Irrelevant speech impairs semantic fluency--namely, lexical retrieval cued by a semantic category name--but only if it is meaningful (forward speech compared to reversed speech or words compared to nonwords). Moreover, speech related semantically to the retrieval category is more disruptive than unrelated speech. That phonemic fluency--in which participants are cued with the first letter of words they are to report--was not disrupted by the mere presence of meaningful speech, only by speech in a related phonemic category, suggests that distraction is not mediated by executive processing load. The pattern of sensitivity to different properties of sound as a function of the type of retrieval cue is in line with an interference-by-process approach to auditory distraction.

Nonexplicit change detection in complex dynamic settings: what eye movements reveal.

OBJECTIVE: We employed a computer-controlled command-and-control (C2) simulation and recorded eye movements to examine the extent and nature of the inability to detect critical changes in dynamic displays when change detection is implicit (i.e., requires no explicit report) to the operator's task. BACKGROUND: Change blindness-the failure to notice significant changes to a visual scene-may have dire consequences on performance in C2 and surveillance operations. METHOD: Participants performed a radar-based risk-assessment task involving multiple subtasks. Although participants were not required to explicitly report critical changes to the operational display, change detection was critical in informing decision making. Participants' eye movements were used as an index of visual attention across the display. RESULTS: Nonfixated (i.e., unattended) changes were more likely to be missed than were fixated (i.e., attended) changes, supporting the idea that focused attention is necessary for conscious change detection. The finding of significant pupil dilation for changes undetected but fixated suggests that attended changes can nonetheless be missed because of a failure of attentional processes. CONCLUSION: Change blindness in complex dynamic displays takes the form of failures in establishing task-appropriate patterns of attentional allocation. APPLICATION: These findings have implications in the design of change-detection support tools for dynamic displays and work procedure in C2 and surveillance.