Grounding Verbal Working Memory: The Case of Serial Order

Annals of the New York Academy of Sciences, 2020

Previous studies have shown that serial order in verbal working memory is spontaneously coded along the horizontal axis (i.e., the spatial positional association response codes (SPoARC) effect), with the initial items being associated with left and the last items being associated with right. These studies have led to the idea that when the cognitive system is confronted with a sequence of items processed verbally and semantically, it internally generates a spatial coordinate frame onto which memoranda can be bound to maintain their serial information. In this study, the interplay between internal and external spatial codes in the mind was investigated by testing the flexibility of the SPoARC effect. A verbal Sternberg probe detection task was used in which the displayed direction of the items during encoding (centrally, from left-to-right and from right-to-left) and the presentation rate (1-and 5-s/item) were manipulated. SPoARC effects were found in all conditions but were reversed in the right-to-left presentation condition. Follow-up analyses revealed no evidence of any spatial cost for the reversal; moreover, it was not influenced by the presentation rates. These findings suggest that space can be flexibly recruited for the spontaneous coding of serial order. The theoretical implications of these observations are discussed.

The Spanish Journal of Psychology, 2013

We investigated the incidental encoding in working memory of event serial order in tasks in which the relevant dimension was visual appearance, spatial location, or visual-spatial conjunction. The participants (n = 60) were asked whether two sequences were identical based on the relevant dimension, and to ignore changes in the irrelevant dimension, that is the order of events. Changes in serial order impaired the performance when sequences were identical; this effect was more pronounced in spatial sequences. It is suggested that the order was incidentally encoded with the relevant information to the task in an earlier stage in the information processing, which explains a different pattern of serial order effect according to the relevant dimension. Although encoded, the serial order may not have affected the visual storage in working memory because it might have been kept in a distinct subcomponent rather than the one that stores the visual characteristic. Moreover, the order may have affected spatial storage because the maintenance of this dimension might be related to a rehearsal mechanism based on serial order of sequence. This conclusion qualifies models that admit the architecture of working memory based on the specificity of encoding and functional interaction between subcomponents of storage.

Smyrnis, Nikolaos, Giovanni d'Avossa, Christos Theleritis, Asimakis Mantas, Alpay Ozcan, and Ioannis Evdokimidis. Parallel processing of spatial and serial order information before moving to a remembered target. . Information storage and retrieval from working memory is limited by the capacity of storage mechanisms and attentional processes. Nevertheless, it has been shown that processing of multiple features can proceed independently in working memory. In this study we investigated how serial order and directional information are processed when executing a movement to a remembered target direction. We compared the performance of 11 healthy subjects in 3 motor working memory tasks, one with a varying spatial memory load, one with a varying serial order memory load, and one in which memory load was varied for both features. We found that the spatial information memory load does not affect the ability to store information about serial order and vice versa. Furthermore, movement response latencies indicated that retrieval of information about both features proceeds simultaneously. These results strongly favor independent, parallel working memory systems for processing space and order information in the motor system.

Studia Psychologica, 2013

Numerous studies have identified and explored the factors that affect order information processing in verbal working memory (WM), whereas little is known about order maintenance in visual WM. To gain better insight into the possible mechanisms of representing order in visual WM, we assessed the extent of serial position and item distance effects on visual WM. 20 students performed a visual WM task. They were asked to encode and maintain either the identity or temporal order of four visual stimuli. The results revealed recency and distance effects congruent with previous studies of verbal WM, however, no primacy effect in accuracy results was detected. Distance was revealed to be closely intertwined with recency, making it difficult to estimate their separate effects on order recognition. These results suggest that order coding in visual WM involves the use of a magnitude of codes similar to those employed in number processing and verbal WM.

A serial reproduction of order with distractors task was developed to make it possible to observe successive snapshots of the learning process at each serial position. The new task was used to explore the effect of several variables on serial memory performance: stimulus content (words, blanks, and pictures), presentation condition (spatial information vs. none), semantically categorized item clustering (grouped vs. ungrouped), and number of distractors relative to targets (none, equal, double). These encoding and retrieval variables, along with learning attempt number, affected both overall performance levels and the shape of the serial position function, although a large and extensive primacy advantage and a small 1-item recency advantage were found in each case. These results were explained well by a version of the scale-independent memory, perception, and learning model that accounted for improved performance by increasing the value of only a single parameter that reflects reduced interference from distant items.

Quarterly journal of experimental psychology (2006), 2016

A largely substantiated view in the domain of working memory is that the maintenance of serial order is achieved by generating associations of each item with an independent representation of its position, so called position markers. Recent studies reported that the ordinal position of an item in verbal working memory interacts with spatial processing. This suggests that position markers might be spatial in nature. However, these interactions were so far observed in tasks implying a clear binary categorization of space (i.e. with left and right responses or targets). Such binary categorizations leave room for alternative interpretations such as congruency between non-spatial categorical codes for ordinal position (e.g. begin and end) and spatial categorical codes for response (e.g. left and right). Here we discard this interpretation by providing evidence that this interaction can also be observed in a task that draws upon a continuous processing of space, the line bisection task. Sp...

Frontiers in psychology, 2014

Psychological Bulletin, 2014

From vocabulary learning to imitating sequences of motor actions, the ability to plan, represent, and recall a novel sequence of items in the correct order is fundamental for many verbal and nonverbal higher level cognitive activities. Here we review phenomena of serial order documented across the verbal, visual, and spatial short-term memory domains and interpret them with reference to the principles of serial order and ancillary assumptions instantiated in contemporary computational theories of memory for serial order. We propose that functional similarities across domains buttress the notion that verbal, visual, and spatial sequences are planned and controlled by a competitive queuing (CQ) mechanism in which items are simultaneously active in parallel and the strongest item is chosen for output. Within the verbal short-term memory CQ system, evidence suggests that serial order is represented via a primacy gradient, position marking, response suppression, and cumulative matching. Evidence further indicates that output interference operates during recall and that item similarity effects manifest during both serial order encoding and retrieval. By contrast, the principles underlying the representation of serial order in the visual and spatial CQ systems are unclear, largely because the relevant studies have yet to be performed. In the spatial domain, there is some evidence for a primacy gradient and position marking, whereas in the visual domain there is no direct evidence for either of the principles of serial order. We conclude by proposing some directions for future research designed to bridge this and other theoretical gaps in the literature.

Journal of Experimental Psychology-learning Memory and Cognition, 1995

Performance on a test of serial memory for the spatial position of a sequence of dots showed similarities to typical results from the serial recall of verbal material: a marked increase in error with increasing list length, a modest rise in error as retention interval increased, and bow-shaped serial position curves. This task was susceptible to interference from both a spatial task (rote tapping) and a verbal task (mouthed articulatory suppression) and also from the presence of irrelevant speech. Effects were comparable to those found with a serial verbal task that was generally similar in demand characteristics to the spatial task. As a generalization, disruption of the serial recall of visuospatial material was more marked if the interference conditions involved a changing sequence of actions or materials, but not if a single event (tap, mouthed utterance, or sound) was repeated.

Journal of Experimental …, 2005

This study examined the role of stimulus characteristics in a visuospatial order reconstruction task in which participants were required to recall the order of sequences of spatial locations. The complexity of the to-be-remembered sequences, as measured by path crossing, path length, and angles, was found to affect serial memory, in terms of both recall accuracy and response times. The results demonstrate that not all sequences are remembered equally and that spatial characteristics of the sequences constitute an important variable in the understanding of visuospatial serial memory. More important, the data suggest that spatial path represents transitional information and that, as is the case in verbal serial memory, transitional information is of critical importance in serial memory.