Search

Experimental measures of working memory that minimize rehearsal and maximize attentional control best predict higher-order cognitive abilities. These tasks fundamentally differ from clinically administered span tasks, which do not control strategy use. Participants engaged in concurrent articulation (to limit rehearsal) or concurrent tapping (to limit attentional refreshing) during forward and backward serial recall with each of three distinct stimulus sets: digits, line drawings of common objects, and images of nonsense symbols. The span tasks used common clinical stopping and scoring procedures. Scores were highest for digits and lowest for novel symbols in all combinations of direction and concurrent task. Furthermore, concurrent articulation and concurrent tapping interfered with backward recall to the same degree. Together, these findings indicate that clinically administered immediate serial recall tasks depend on both rehearsal and long-term lexical knowledge making it difficult to use these tasks to separate problems in language ability from problems in attention.

Work by Flavell, Beach, and Chinsky indicated a change in the spontaneous production of overt verbalization behaviors when comparing young children (age 5) with older children (age 10). Despite the critical role that this evidence of a change in verbalization behaviors plays in modern theories of cognitive development and working memory, there has been only one other published near replication of this work. In this Registered Replication Report, we relied on researchers from 17 labs who contributed their results to a larger and more comprehensive sample of children. We assessed memory performance and the presence or absence of verbalization behaviors of young children at different ages and determined that the original pattern of findings was largely upheld: Older children were more likely to verbalize, and their memory spans improved. We confirmed that 5- and 6-year-old children who verbalized recalled more than children who did not verbalize. However, unlike Flavell et al., substantial proportions of our 5- and 6-year-old samples overtly verbalized at least sometimes during the picture memory task. In addition, continuous increase in overt verbalization from 7 to 10 years old was not consistently evident in our samples. These robust findings should be weighed when considering theories of cognitive development, particularly theories concerning when verbal rehearsal emerges and relations between speech and memory.

Purpose The aim of this study was to quantify the portion of variance in several measures suggested to be indicative of peripheral noise-induced cochlear synaptopathy and hidden hearing disorder that can be attributed to individual cognitive capacity. Method Regression and relative importance analysis was used to model several behavioral and physiological measures of hearing in 32 adults ranging in age from 20 to 74 years. Predictors for the model were hearing sensitivity and performance on a number of cognitive tasks. Results There was a significant influence of cognitive capacity on several measures of cochlear synaptopathy and hidden hearing disorder. These measures include frequency modulation detection threshold, time-compressed word recognition in quiet and reverberation, and the strength of the frequency-following response of the speech-evoked auditory brainstem response. Conclusions Measures of hearing that involve temporal processing are significantly influenced by cognitive abilities, specifically, short-term and working memory capacity, executive function, and attention. Research using measures of temporal processing to diagnose peripheral disorders, such as noise-induced synaptopathy, need to consider cognitive influence even in a young, healthy population.

Purpose The current study adopts a systematic approach to the examination of working memory components in pediatric cochlear implant (CI) users by separately assessing contributions of encoding, storage, and retrieval. Method Forty-nine long-term CI users and 56 typically hearing controls completed forward and backward span tasks with 3 stimulus sets: visually presented digits, pictures of concrete nouns, and novel symbols. In addition, measures associated with each memory stage were collected: Rapid digit naming provided an estimate of phonological recoding speed, nonword repetition assessed the robustness of representations within phonological storage, and vocabulary knowledge (as measured by the Peabody Picture Vocabulary Test; Dunn & Dunn, 1997 ) estimated redintegration abilities during retrieval. Results Linear mixed modeling revealed that digit naming speed and vocabulary knowledge were consistently related to short-term and working memory span in both CI users and typically hearing controls. However, nonword repetition only contributed to the model for short-term memory. Conclusions Nonword repetition, an index of phonological storage, explained little of the individual variability inworking memory differences between CI users and typically hearing peers. On the other hand, individual differences in encoding and retrieval explained a significant amount of outcome variability in both short-term and working memory tasks. Differences between CI users and typically hearing peers in working memory therefore appear to reflect process components of encoding and retrieval and not simply differences in memory storage. Supplemental Material https://doi.org/10.23641/asha.7849394

Purpose The purpose of this study was to report how verbal rehearsal spee d (VRS), a form of covert speech used to maintain verbal information in working memory, and another verbal processing speed measure, perceptual encoding speed, are related to 3 domains of executive function (EF) at risk in cochlear implant (CI) users: verbal working memory, fluency-speed, and inhibition-concentration. Method EF, speech perception, and language outcome measures were obtained from 55 prelingually deaf, long-term CI users and matched controls with normal hearing (NH controls). Correlational analyses were used to assess relations between VRS (articulation rate), perceptual encoding speed (digit and color naming), and the outcomes in each sample. Results CI users displayed slower verbal processing speeds than NH controls. Verbal rehearsal speed was related to 2 EF domains in the NH sample but was unrelated to EF outcomes in CI users. Perceptual encoding speed was related to all EF domains in both groups. Conclusions Verbal rehearsal speed may be less influential for EF quality in CI users than for NH controls, whereas rapid automatized labeling skills and EF are closely related in both groups. CI users may develop processing strategies in EF tasks that differ from the covert speech strategies routinely employed by NH individuals. Supplemental Material https://doi.org/10.23641/asha.6170501

It is well-accepted that younger children perform more poorly than older children and adults on tests of working memory, the current-task information kept in an active state for short-term recall. It is clear that the development of working memory ability is an important component of cognitive development across many tasks (e.g., Andrews & Halford, 2002; Cowan et al., 2005, 2006; Gathercole, Pickering, Ambridge, & Wearing, 2004; Hitch, Towse, & Hutton, 2001; Johnson, Im-Bolter, & Pascual-Leone, 2003). What has been more controversial for many years is the reason behind the age differences in working memory performance. One simple hypothesis, the one advocated here, is that some brain system operates by retaining a limited number of items in an active form, and that this brain system holds fewer items in young children than in older participants (e.g., Burtis, 1982; Case, 1995; Cowan, 2001; Pascual-Leone & Smith, 1969). The notion that there is a working memory faculty limited to no more than a few items is supported by considerable recent research in adults (Awh, Barton, & Vogel, 2007; Cowan & Rouder, 2009; Rouder et al., 2008; Zhang & Luck, 2008; for an opposing view see Bays & Husain, 2008, 2009). The challenge for advocates of a capacity-growth hypothesis, however, is that it is not logically necessary; other possibilities exist (e.g., Barrouillet, Gavens, Vergauwe, Gaillard, & Camos, 2009; Case, Kurland, & Goldberg, 1982; Dempster, 1991; Hulme & Tordoff, 1989). The older participants may excel at focusing on more task-relevant information, in which case the holding system in the brain may be more cluttered by information irrelevant to the task at hand in younger children. Also, older participants may be better able to encode the stimuli in a manner that allows the information to be retrieved. In particular, they may form verbal labels for the stimuli that allow these stimuli to be retained using multiple brain systems, adding redundancy to the representation and making recall more reliable. In fact, verbal rehearsal is one of the main ways in which mnemonic processing improves in childhood (e.g., Cowan, Cartwright, Winterowd, & Sherk, 1987; Cowan, Saults, & Morey, 2006; Flavell, Beach, & Chinsky, 1966; Ornstein, Naus, & Liberty, 1975; Tam, Jarrold, Baddeley, & Sabatos-DeVito, 2010). The present research was designed to determine whether an age difference in working memory performance could be obtained across manipulations in factors that could affect the encoding of the stimuli. It was based on the procedure used by Cowan, Morey, AuBuchon, Zwilling, and Gilchrist (2010), illustrated in Figure 1. On each trial in that study, an array was presented for 500 ms and the task was to retain items from the array for a probe item recognition test shortly afterward. The probe either was identical to the array item in the same location or differed from that array item in color, in one of three ways shown in the figure. In the most critical condition, the one to be replicated here, the instructions said to pay attention to items in one shape and not another (e.g., circles and not triangles) throughout the session. The probe tested was in the attended shape 80% of the time, but in the other shape the remaining 20% of the time. After Gold et al. (2006), it was possible to obtain two meaningful measures from the results. First, the sum of items recalled from the attended and unattended (or less-attended) shape provided an estimate of the number of items held in working memory. Second, the difference between the number of items recalled in the attended versus unattended shape provided an estimate of the efficiency of the allocation of attention preferentially to the shape that was usually tested, and therefore more relevant than the other shape for maximum performance. Figure 1 After Cowan, Morey, AuBuchon, Zwilling, and Gilchrist (2010, Figure 2). An illustration of the array memory procedure. The present study differed from Cowan et al. in that the array items were presented one at a time, and in that a verbal response was ... Results of the previous study were clearest for small arrays, which included two circles and two triangles. Cowan et al. (2010) found that children in Grades 1-2 recalled far fewer items in total, but that they favored the relevant shape to the same degree as older children (Grades 6-7) or adults (college students). This strongly suggests that visual working memory capacity increases with age in childhood. The reason for this finding, however, is not yet clear. It could be that the effect occurs because children are not as good at entering the items from a brief, concurrent visual display into working memory. To examine whether that encoding difference can explain the age difference in capacity, the present experiment mirrored that of Cowan et al. but with the items presented one at a time, at a slow rate of 1 s per item (Figure 2). Figure 2 Comparison of the simultaneous array presentation method of Cowan, Morey, AuBuchon, Zwilling, and Gilchrist (2010) to the sequential array presentation method of the present study. If age differences in the number of items retained in working memory survive this change in procedure, though, there is still an explanation aside from basic capacity growth. It could be that this slower procedure allows time for older participants to engage in verbal encoding and rehearsal of the visual items, enhancing recall. To examine this factor, each participant carried out trials in each of three articulation conditions. In the first condition, the participant remained silent and therefore was free to adopt whatever strategy he or she wished. In a second condition, the color of each item was to be named as it was presented. This should enhance recall generally for individuals who did not spontaneously name the colors. Finally, in a third condition, the participant was to say the word “wait” after each item presented. This is essentially an articulatory suppression condition (Baddeley, 1986) in which the need to say a word irrelevant to the memory task interrupts more task-relevant verbal processing, such as labeling and covert rehearsal. If the working memory advantage of older participants in this procedure accrues only because they use verbal processing better than younger children, then the age difference might be substantially diminished when naming of the color is required (because item colors are then verbally labeled in all groups, instead of just the older participants) and it should be diminished also when an irrelevant word is required (because it disrupts verbal processing that may otherwise be an advantage for older participants). This last condition, presented after the participants are well-practiced in the task, provides the best indication of each age group's basic visual working memory capacity without the assistance of verbal strategies.

Previous studies have indicated that visual working memory performance increases with age in childhood, but it is not clear why. One main hypothesis has been that younger children are less efficient in their attention; specifically, they are less able to exclude irrelevant items from working memory to make room for relevant items. We examined this hypothesis by measuring visual working memory capacity under a continuum of five attention conditions. A recognition advantage was found for items to be attended as opposed to ignored. The size of this attention-related effect was adult-like in young children with small arrays, suggesting that their attention processes are efficient even though their working memory capacity is smaller than that of older children and adults. With a larger working memory load, this efficiency in young children was compromised. The efficiency of attention cannot be the sole explanation for the capacity difference.

Individual differences in verbal working memory underlie the substantial variation routinely observed in speech and language outcomes of deaf children with cochlear implants. In this chapter we describe the nature of verbal working memory and its component processes: encoding, maintenance, and retrieval. We then present evidence suggesting that the verbal working memory delays and disturbances found recently in many young CI users are not idiopathic or anomalous but are consistent with a large body of earlier research in verbal working memory development in normal-hearing, typically-developing children. Specifically, pre-lingually deaf CI users appear to be at risk for slow and inefficient phonological recoding and verbal rehearsal processes because of the early atypical auditory and language environments in which their verbal working memory systems develop.

Objective: To determine whether early-implanted, long-term cochlear implant (CI) users display delays in verbal short-term and working memory capacity when processes related to audibility and speech production are eliminated. Design: Twenty-three long-term CI users and 23 normal-hearing controls each completed forward and backward digit span tasks under testing conditions that differed in presentation modality (auditory or visual) and response output (spoken recall or manual pointing). Results: Normal-hearing controls reproduced more lists of digits than the CI users, even when the test items were presented visually and the responses were made manually via touchscreen response. Conclusions: Short-term and working memory delays observed in CI users are not due to greater demands from peripheral sensory processes such as audibility or from overt speech-motor planning and response output organization. Instead, CI users are less efficient at encoding and maintaining phonological representations in verbal short-term memory using phonological and linguistic strategies during memory tasks.

The nature of the childhood development of immediate recall has been difficult to determine. There could be a developmental increase in either the number of chunks held in working memory or the use of grouping to make the most of a constant capacity. In 3 experiments with children in the early elementary school years and adults, we show that improvements in the immediate recall of word and picture lists come partly from increases in the number of chunks of items retained in memory. This finding was based on a distinction between access to a studied group of items (i.e., recall of at least 1 item from the group) and completion of the accessed group (i.e., the proportion of the items recalled from the group). Access rates increased with age, even with statistical controls for completion rates, implicating development of capacity in chunks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)