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We analyzed a Japanese lexical database to investigate the structure of the lexical environment based on the hypothesis that the lexical environment is optimized for the functioning of verbal working memory. Our prediction was that, as a consequence of the cultural transmission of language, low‐imageable meanings tend to be represented by frequent phonological patterns in the current vocabulary rather than infrequent phonological patterns. This prediction was based on two findings of previous laboratory studies on verbal working memory. (1) The quality of phonological (phonemic and accent) representations in verbal working memory depends on phonological regularity knowledge; therefore, short‐term phonological representations are less robust for words with infrequent phonological patterns. (2) Phonological representations are underpinned by contributions from semantic knowledge; therefore, phonological representations of highly imageable words are more robust than those for low‐imageable words. Our database analyses show that nouns with less imageable meanings tend to be associated with more frequent phonological patterns in Japanese vocabulary. This lexical structure can maintain the quality of phonological representations in verbal working memory through contributions of semantic and phonological regularity knowledge. Larger semantic contributions compensate for the less robust phonological representations of infrequent phonological forms. The quality of phonological representations is preserved by phonological regularity knowledge when larger semantic contributions are not expected. [ABSTRACT FROM AUTHOR]

Evidence supporting the idea that serial-order verbal working memory is underpinned by long-term knowledge has accumulated over more than half a century. Recent studies using natural-language statistics, artificial statistical-learning techniques, and the Hebb repetition paradigm have revealed multiple types of long-term knowledge underlying serial-order verbal working memory performance. These include (a) element-to-element association knowledge, which slowly accumulates through extensive exposure to an exemplar; (b) position–element knowledge, which is acquired through several encounters with an exemplar; and (c) whole-sequence knowledge, which is captured by the Hebb repetition paradigm and acquired rapidly with a few repetitions. Arguably, the first two are a basis for fluent and efficient language usage, and the third is a basis for vocabulary learning. Thus, statistical-learning mechanisms (and possibly episodic-learning mechanisms) may form the foundation of language acquisition and language processing, which characterize linguistic long-term knowledge for verbal working memory. [ABSTRACT FROM AUTHOR]

Working memory (WM) helps maintain information during a variety of cognitive activities in scholastic and social situations. This study focused on a social aspect of WM, specifically, how it maintains information related to people. We investigated person-based organisation of information across four experiments using the reading span task (RST). Person information (i.e., an occupational title) was provided with sentences manipulated across conditions. In Experiment 1, consistent with the assumption that person-based organisation exists in WM, participants performed better when they could easily organise target items in a person-based manner (person-based organisation) than when they were prevented from using such information. Experiments 2 and 3 investigated the process of person-based organisation using alphabetical letters as targets (unlike words in Experiment 1), which prevented possible semantic associations between person information and target items. Experiment 2 replicated Experiment 1, suggesting that contextual retrieval is critical in person-based organisation. Experiment 3 showed the person-based organisation effect even after controlling for the difficulty of the process component in the RST. The results of Experiments 2 and 3 suggest that person information could serve as contextual retrieval cues in WM. Experiment 4, which did not show the organisation effect based on information about an object (i.e., a fruit name), suggests along with Experiments 1 to 3 that the observed organisation effect in Experiments 1 to 3 was specific to person information. In addition to showing the enhanced WM performance by person-based organisation, we have suggested contextual cue-dependent retrieval as the underlying cognitive process. [ABSTRACT FROM AUTHOR]

Recent studies of short-term serial order memory have suggested that the maintenance of order information does not involve domain-specific processes. We carried out two dual-task experiments aimed at resolving several ambiguities in those studies. In our experiments, encoding and response of one serial reconstruction task was embedded within encoding and response of a concurrent serial reconstruction task. Order demands in both tasks were independently varied so as to find revealing patterns of interference between the two tasks. In Experiment 1, participants were to maintain and reconstruct the order of a list of verbal materials, while maintaining a list of spatial materials or vice-versa. Increasing the order demands in the outer reconstruction task resulted in small or non-reliable performance decrements in the embedded reconstruction task. Experiment 2 sought to compare these results against two same-domain baseline conditions (two verbal lists or two spatial lists). In all conditions, increasing order demands in the outer task resulted in small or non-reliable performance decrements in the embedded task. However, performance in the embedded tasks was generally lower in the same-domain baseline conditions than in the cross-domain conditions. We argue that the main effect of domain in Experiment 2 indicates the contribution of domain-specific processes to short-term serial order maintenance. In addition, we interpret the failure to find consistent cross-list interference irrespective of domain as indicating the involvement of grouping mechanisms in concurrently performed serial order tasks. [ABSTRACT FROM AUTHOR]

We report three experiments in which participants performed written serial recall of visually presented verbal sequences with items varying in visual similarity. In Experiments 1 and 2 native speakers of Japanese recalled visually presented Japanese Kanji characters. In Experiment 3, native speakers of English recalled visually presented words. In all experiments, items varied in visual similarity and were controlled for phonological similarity. For Kanji and for English, performance on lists comprising visually similar items was overall poorer than for lists of visually distinct items across all serial positions. For mixed lists in which visually similar and visually distinct items alternated through the list, a clear 'zig-zag' pattern appeared with better recall of the visually distinct items than for visually similar items. This is the first time that this zig-zag pattern has been shown for manipulations of visual similarity in serial-ordered recall. These data provide new evidence that retaining a sequence of visual codes relies on similar principles to those that govern the retention of a sequence of phonological codes. We further illustrate this by demonstrating that the data patterns can be readily simulated by at least one computational model of serial-ordered recall, the Primacy model (Page and Norris, Psychological Review, 105(4), 761-81, ). Together with previous evidence from neuropsychological studies and experimental studies with healthy adults, these results are interpreted as consistent with two domain-specific, limited-capacity, temporary memory systems for phonological material and for visual material, respectively, each of which uses similar processes that have evolved to be optimal for retention of serial order. [ABSTRACT FROM AUTHOR]

According to the multicomponent view of working memory, both auditory-nonverbal information and auditory-verbal information are stored in a phonological code and are maintained by an articulation-based rehearsal mechanism (Baddeley, 2012). Two experiments have been carried out to investigate this hypothesis using sound materials that are difficult to label verbally and difficult to articulate. Participants were required to maintain 2 to 4 sounds differing in timbre over a delay of up to 12 seconds while performing different secondary tasks. While there was no convincing evidence for articulatory rehearsal as a main maintenance mechanism for auditory-nonverbal information, the results suggest that processes similar or identical to auditory imagery might contribute to maintenance. We discuss the implications of these results for multicomponent models of working memory. [ABSTRACT FROM AUTHOR]

Caplan and colleagues have recently explained paired-associate learning and serial-order learning with a single-mechanism computational model by assuming differential degrees of isolation. Specifically, two items in a pair can be grouped together and associated to positional codes that are somewhat isolated from the rest of the items. In contrast, the degree of isolation among the studied items is lower in serial-order learning. One of the key predictions drawn from this theory is that any variables that help chunking of two adjacent items into a group should be beneficial to paired-associate learning, more than serial-order learning. To test this idea, the role of visual representations in memory for spoken verbal materials (i.e., imagery) was compared between two types of learning directly. Experiment 1 showed stronger effects of word concreteness and of concurrent presentation of irrelevant visual stimuli (dynamic visual noise: DVN) in paired-associate memory than in serial-order memory, consistent with the prediction. Experiment 2 revealed that the irrelevant visual stimuli effect was boosted when the participants had to actively maintain the information within working memory, rather than feed it to long-term memory for subsequent recall, due to cue overloading. This indicates that the sensory input from irrelevant visual stimuli can reach and affect visual representations of verbal items within working memory, and that this disruption can be attenuated when the information within working memory can be efficiently supported by long-term memory for subsequent recall. [ABSTRACT FROM AUTHOR]

Theory of mind (ToM) refers to the ability to reason about the mental states of others. An increasing number of studies have revealed that working memory (WM) plays an important role in ToM. The present study applied WM loads to adults during a ToM task in order to investigate the impact on mental-state reasoning performance. The task required participants to estimate the probabilities of several possible behaviours for a protagonist following the presentation of a ToM story. Participants were also required to maintain a meaningless two- (light WM load) or seven-letter English alphabet string (heavy WM load) during story comprehension and mental-state reasoning. The results show that the combination of light WM load applied during story comprehension with heavy WM load during mental-state reasoning results in an overestimation of the probability that the protagonist's behaviour will accord with a participant's knowledge. Conversely, a heavy WM load applied during story comprehension, regardless of the type of WM load during mental-state reasoning, did not result in this probability estimation bias. We discuss these findings from the perspective of a WM representation account. [ABSTRACT FROM AUTHOR]

Abstract: Although an increasing number of studies on adults have indicated that working memory (WM) contributes to the ability to understand the mental states of others (i.e., theory of mind), the detailed mechanism by which WM contributes to successful reasoning has not previously been revealed. This study shows that WM modulates the degree of attribution of one''s own knowledge to others'' mental states. Participants were asked to read a story twice (Experiment 2) or as carefully as possible (Experiment 3) and to estimate the probability percentages of possible choices for a naive protagonist''s behavior. The participants were then asked to maintain either a two- or seven-letter alphabet string (i.e., a light or heavy WM load, respectively) during the probability estimation but not during the story comprehension. The results showed that compared to the participants with a light WM load, those with a heavy WM load estimated a significantly higher probability of the choice indicating that the protagonist would behave on the basis of a fact that the participants knew but the protagonist did not. This result indicates that WM moderates the extent to which adults attribute their own knowledge to others'' mental states. The role of WM in theory of mind and in heuristic strategy for making probability judgments was then discussed. [Copyright &y& Elsevier]

In working memory (WM) span tests participants have to maintain to-be-remembered information while processing other, potentially distracting, information. Previous studies have shown that WM span scores are greater when span lists start with a long processing task and end with a short processing task than when these processing tasks are presented in the reverse order (e.g., Towse, Hitch, & Hutton, 2000). In Experiment 1, we obtained a similar stimulus order effect in a reasoning span test, using reasoning sentences that were equated for length in terms of the number of constituent words, but which differed in processing complexity; span scores were greater when lists began with a complex sentence and ended with a simple sentence than when this stimulus order was reversed. In Experiment 2, the stimulus order effect was not found when processing duration was held constant while sentence complexity was varied using a computer-paced moving window presentation paradigm. These results suggest that duration-based constraints can affect degree of forgetting independently of the load generated during processing phases in WM span performance and therefore imply that time-related forgetting can occur in WM span tests, particularly when the difficulty of the processing component blocks active maintenance of to-be-remembered material. [ABSTRACT FROM AUTHOR]

Abstract: In a series of three experiments, native speakers of Japanese performed serial ordered written recall of visually presented Japanese kanji characters that varied systematically in visual and phonological similarity. Overall effects of phonological similarity were observed for retention of serial order under silent reading in Experiments 1 and 3 and they disappeared in articulatory suppression conditions in Experiments 2 and 3. All three experiments showed main effects of visual similarity even in articulatory suppression conditions in Experiments 2 and 3. This indicated spontaneous use of visual codes in immediate serial recall. It is suggested that any models of serial order memory should incorporate domain specificity. [Copyright &y& Elsevier]

Abstract: In working memory (WM) span tests, participants maintain memory items while performing processing tasks. In this study, we examined the impact of task processing requirements on memory-storage activities, looking at the stimulus order effect and the impact of storage requirements on processing activities, testing the processing time effect in WM span tests. The stimulus order effect is a phenomenon whereby span scores are higher when span lists end with a shorter task than when they end with a longer task. The processing time effect refers to the phenomenon whereby the processing speed slows for the later processing positions in a list in WM span tests when participants have more memory items to remember. Two experiments demonstrated the domain-specific nature of the stimulus order effect, which was observed only when the processing and storage materials were in the same domain (either verbal or visuospatial domains), and the domain-general nature of the processing time effect, which was observed with any combination of processing and storage materials. Although the domain specificity of the stimulus order effect is compatible with the representation-based interference view proposed by Saito and Miyake [Saito, S., & Miyake, A. (2004). On the nature of forgetting and the processing-storage relationship in reading span performance. Journal of Memory and Language, 50, 425–443.], the domain generality of the processing time effect is inconsistent with their account and indicates the involvement of a central bottleneck in WM span performance. [Copyright &y& Elsevier]

Four experiments examined the nature of forgetting and the processing–storage relationship during performance on a prevalent working memory task, the reading span test. Using two different presentation paradigms, Experiments 1 and 2 replicated finding that the Short-Final lists, which presented a long sentence first and a short sentence last, led to better recall performance than the reverse-order Long-Final lists. This effect was still obtained when the retention duration for the target words was held constant and the amount of sentence processing required during that interval was varied (Experiment 3). However, the effect disappeared when the retention duration was varied while holding constant the amount of sentence processing required (Experiment 4). These results suggest that the amount of processing activities, not the sheer passage of time, may be the critical factor underlying the sentence order effect, thereby challenging purely time-based explanations of forgetting during reading span performance. In addition, the analysis of reading times (Experiment 1) revealed that the number of memory items had a subtle yet reliable negative effect on reading times, suggesting that the processing and storage requirements of the reading span test are not completely independent. [Copyright &y& Elsevier]

The Hebb repetition effect on serial-recall task refers to the improvement in the accuracy of recall of a repeated list (e.g., repeated in every 3 trials) over random non-repeated lists. Previous research has shown that both temporal position and neighboring items need to be the same on each repetition list for the Hebb repetition effect to occur, suggesting chunking as one of its underlying mechanisms. Accordingly, one can expect absence of the Hebb repetition effect in a complex span task, given that the sequence is interrupted by distractors. Nevertheless, one study by Oberauer, Jones, and Lewandowsky (2015, Memory & Cognition, 43[6], 852–865) showed evidence of the Hebb repetition effect in a complex span task. Throughout four experiments, we confirmed the Hebb repetition effect in complex span tasks, even when we included distractors in both encoding and recall phases to avoid any resemblance to a simple span task and minimized the possibility of chunking. Results showed that the Hebb repetition effect was not affected by the distractors during encoding and recall. A transfer cycle analysis showed that the long-term knowledge acquired in the complex span task can be transferred to a simple span task. These findings provide the first insights on the mechanism behind the Hebb repetition effect in complex span tasks; it is at least partially based on the same mechanism that improves recall performance by repetition in simple span tasks. [ABSTRACT FROM AUTHOR]

To complete complex tasks, individuals must actively maintain task rules to direct behavior correctly. Failure to use task rules appropriately, termed goal neglect, has been shown across both vocal and manual response modalities. However, previous goal maintenance studies have differed not only in the response modality that they require, but also in the complexity of the stimulus-response mappings that participants must use during the task. The present study examines the effects of both response modality and stimulus-response mapping complexity, separately, on the rate of goal neglect in a modification of a classic goal maintenance task. Seventy-two younger adults were administered a shape-monitoring task, with three between-subjects response conditions: a vocal response with a simple stimulus-response mapping, a vocal response with a complex stimulus-response mapping, and a manual response with a complex stimulus-response mapping. Contrasting the rate at which task rules were neglected between response conditions showed that participants using complex stimulus-response mappings committed more frequent goal neglect than those using simple mappings, but that participants using vocal or manual responses did not differ in their rate of goal neglect once both responses required complex mappings. This suggests that the need to represent novel and complex stimulus-response mappings, of any modality, at the same time as novel task rules within working memory leads to some task rules being insufficiently maintained. [ABSTRACT FROM AUTHOR]

Generating random number sequences is a popular psychological task often used to measure executive functioning. We explore random generation under “joint cognition” instructions; pairs of participants take turns to compile a shared response sequence. Across three studies, we point to six key findings from this novel format. First, there are both costs and benefits from group performance. Second, repetition avoidance occurs in dyadic as well as individual production settings. Third, individuals modify their choices in a dyadic situation such that the pair becomes the unit of psychological function. Fourth, there is immediate contagion of sequence stereotypy amongst the pairs (i.e., each contributor “owns” their partner’s response). Fifth, dyad effects occur even when participants know their partner is not interacting with them (Experiment 2). Sixth, ironically, directing participants’ efforts away from their shared task responsibility can actually benefit conjoint performance (Experiment 3). These results both constrain models of random generation and illuminate processes of joint cognition. [ABSTRACT FROM AUTHOR]

Many previous studies have explored and confirmed the influence of long-term phonological representations on phonological short-term memory. In most investigations, phonological effects have been explored with respect to phonotactic constraints or frequency. If interaction between long-term memory and phonological short-term memory is a generalized principle, then other phonological characteristics-that is, suprasegmental aspects of phonology-should also exert similar effects on phonological short-term memory. We explored this hypothesis through three immediate serial-recall experiments that manipulated Japanese nonwords with respect to lexical prosody (pitch-accent type, reflecting suprasegmental characteristics) as well as phonotactic frequency (reflecting segmental characteristics). The results showed that phonotactic frequency affected the retention not only of the phonemic sequences, but also of pitch-accent patterns, when participants were instructed to recall both the phoneme sequence and accent pattern of nonwords. In addition, accent pattern typicality influenced the retention of the accent pattern: Typical accent patterns were recalled more accurately than atypical ones. These results indicate that both long-term phonotactic and lexical prosodic knowledge contribute to phonological short-term memory performance. [ABSTRACT FROM AUTHOR]

In a series of five experiments, we studied the effect of a visual suffix on the retention in short-term visual memory of both individual visual features and objects involving the binding of two features. Experiments 1A, 1B, and 2 involved suffixes consisting of features external to the to-be-remembered set and revealed a modest but equivalent disruption on individual and bound feature conditions. Experiments 3A and 3B involved suffixes comprising features that could potentially have formed part of the to-be-remembered set (but did not on that trial). Both experiments showed greater disruption of retention for objects comprising bound features than for their individual features. The results are interpreted as differentiating two components of suffix interference, one affecting memory for features and bindings equally, the other affecting memory for bindings. The general component is tentatively identified with the attentional cost of operating a filter to prevent the suffix from entering visual working memory, whereas the specific component is attributed to the particular fragility of bound representations when the filter fails. [ABSTRACT FROM AUTHOR]