Previous studies indicate 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 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 5 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 is compromised. The efficiency of attention cannot be the sole explanation for the capacity difference.

Why does visual working memory performance increase with age in childhood? One recent study ruled out the possibility that the basic cause is a tendency in young children to clutter working memory with less-relevant items (within a concurrent array, colored items presented in one of two shapes). The age differences in memory performance, however, theoretically could result from inadequate encoding of the briefly-presented array items by younger children. We replicated the key part of the procedure in children 6-8 and 11-13 years old and college students (total N=90), but with a much slower, sequential presentation of the items to ensure adequate encoding. We also required verbal responses during encoding to encourage or discourage labeling of item information. Although verbal labeling affected performance, age differences persisted across labeling conditions, further supporting the existence of a basic growth in capacity.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 shortterm 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., 2005Gathercole, 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).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, Flavell, Beach, & Chinsky, 1966;Ornstein, Naus, & Liberty, 1975;Tam, Jarrold, Baddeley, & Sabatos-DeVito, 2010)...

OBJECTIVES Determine if 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 which 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 utilizing phonological and linguistic strategies during memory tasks.

Purpose This study investigated long-term speech intelligibility outcomes in 63 prelingually deaf children, adolescents, and young adults who received cochlear implants (CIs) before age 7 (M = 2;11 [years;months], range = 0;8–6;3) and used their implants for at least 7 years (M = 12;1, range = 7;0–22;5). Method Speech intelligibility was assessed using playback methods with naïve, normal-hearing listeners. Results Mean intelligibility scores were lower than scores obtained from an age- and nonverbal IQ–matched, normal-hearing control sample, although the majority of CI users scored within the range of the control sample. Our sample allowed us to investigate the contribution of several demographic and cognitive factors to speech intelligibility. CI users who used their implant for longer periods of time exhibited poorer speech intelligibility scores. Crucially, results from a hierarchical regression model suggested that this difference was due to more conservative candidacy criteria in CI users with more years of use. No other demographic variables accounted for significant variance in speech intelligibility scores beyond age of implantation and amount of spoken language experience (assessed by communication mode and family income measures). Conclusion Many factors that have been found to contribute to individual differences in language outcomes in normal-hearing children also contribute to long-term CI users’ ability to produce intelligible speech.

Purpose To report how verbal rehearsal speed, 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 three 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 normal hearing (NH) controls. Correlational analyses were used to assess relations between verbal rehearsal speed (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 two EF domains in the NH sample but was unrelated to EF outcomes in CI users. Perceptual encoding speed was related to all domains of EF in both groups. Conclusions Verbal rehearsal speed may be less influential for the quality of EF 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.