1
|
Blankenship TL, Kibbe MM. "Plan chunking" expands 3-year-olds' ability to complete multiple-step plans. Child Dev 2023; 94:1330-1339. [PMID: 37092570 DOI: 10.1111/cdev.13929] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 04/25/2023]
Abstract
The ability to use knowledge to guide the completion of goals is a critical cognitive skill, but 3-year-olds struggle to complete goals that require multiple steps. This study asked whether 3-year-olds could benefit from "plan chunking" to complete multistep goals. Thirty-two U.S. children (range = 35.75-46.59 months; 18 girls; 9 white, 3 mixed race, 20 unknown; tested between July 2020 and April 2021) were asked to complete "treasure maps," retrieving four colored map pieces by pressing specific buttons on a "rainbow box." Children completed more of the four-step sequence correctly when the steps were presented in a way that encouraged chunking the steps into pairs. These findings suggest a potential mechanism supporting memory-guided planning abilities in early childhood.
Collapse
Affiliation(s)
| | - Melissa M Kibbe
- Department of Psychological & Brain Sciences, Boston University, Boston, Massachusetts, USA
| |
Collapse
|
2
|
Cheng C, Kibbe MM. Is Nonsymbolic Arithmetic Truly "Arithmetic"? Examining the Computational Capacity of the Approximate Number System in Young Children. Cogn Sci 2023; 47:e13299. [PMID: 37303302 DOI: 10.1111/cogs.13299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 01/09/2023] [Accepted: 05/10/2023] [Indexed: 06/13/2023]
Abstract
Young children with limited knowledge of formal mathematics can intuitively perform basic arithmetic-like operations over nonsymbolic, approximate representations of quantity. However, the algorithmic rules that guide such nonsymbolic operations are not entirely clear. We asked whether nonsymbolic arithmetic operations have a function-like structure, like symbolic arithmetic. Children (n = 74 4- to -8-year-olds in Experiment 1; n = 52 7- to 8-year-olds in Experiment 2) first solved two nonsymbolic arithmetic problems. We then showed children two unequal sets of objects, and asked children which of the two derived solutions should be added to the smaller of the two sets to make them "about the same." We hypothesized that, if nonsymbolic arithmetic follows similar function rules to symbolic arithmetic, then children should be able to use the solutions of nonsymbolic computations as inputs into another nonsymbolic problem. Contrary to this hypothesis, we found that children were unable to reliably do so, suggesting that these solutions may not operate as independent representations that can be used inputs into other nonsymbolic computations. These results suggest that nonsymbolic and symbolic arithmetic computations are algorithmically distinct, which may limit the extent to which children can leverage nonsymbolic arithmetic intuitions to acquire formal mathematics knowledge.
Collapse
Affiliation(s)
- Chen Cheng
- Division of Social Science, Hong Kong University of Science and Technology
| | - Melissa M Kibbe
- Department of Psychological and Brain Sciences, Boston University
| |
Collapse
|
3
|
Haj ME, Kessels RPC, Urso L, Nandrino JL. Chunking to improve verbal forward spans in Korsakoff's syndrome. APPLIED NEUROPSYCHOLOGY. ADULT 2020; 27:150-157. [PMID: 30183427 DOI: 10.1080/23279095.2018.1499023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Chunking is a mnemonic strategy that involves organizing information into appropriate units. Our article examined the use of this strategy on forward and backward span performance in Korsakoff's syndrome. Fifteen patients with Korsakoff's syndrome and 17 age-and-education matched healthy controls participated to the study. Digit span performance (both forward and backward) was tested before and after chunking training. Results demonstrated an increased performance on the forward spans after chunking training in the patients with Korsakoff's syndrome, but no beneficial effect was observed on the backward spans in these participants. Controls demonstrated a chunking effect on both forward and backward span performance. Our findings suggest that a simple training in chunking may be useful as part of a cognitive strategy training for improving working memory performance in patients with Korsakoff's syndrome.
Collapse
Affiliation(s)
- Mohamad El Haj
- Laboratoire de Psychologie des Pays de la Loire (EA 4638), Université de Nantes, Nantes, France.,Centre Hospitalier de Tourcoing, Unité de Gériatrie, Tourcoing, France.,Institut Universitaire de France, Paris, France
| | - Roy P C Kessels
- Cognition and Behaviour, Radboud University Donders Institute for Brain, Nijmegen, The Netherlands.,Centre for Excellence for Korsakoff and Alcohol-Related Cognitive Disorders, Vincent van Gogh Institute for Psychiatry, Venray, The Netherlands.,Department of Medical Psychology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Laurent Urso
- Service d'addictologie, Centre Hospitalier de Roubaix, Roubaix, France
| | - Jean Louis Nandrino
- CNRS CHU Lille, et UMR 9193 - SCALab - Sciences Cognitives Sciences Affectives, Univ. Lille, Lille, France
| |
Collapse
|
4
|
Aguilar-Mediavilla E, Buil-Legaz L, López-Penadés R, Sanchez-Azanza VA, Adrover-Roig D. Academic Outcomes in Bilingual Children With Developmental Language Disorder: A Longitudinal Study. Front Psychol 2019; 10:531. [PMID: 30915007 PMCID: PMC6421289 DOI: 10.3389/fpsyg.2019.00531] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/22/2019] [Indexed: 01/09/2023] Open
Abstract
Previous studies have shown that most English-speaking children with language difficulties show academic difficulties during their schooling. The present study aimed to describe the academic achievement of children speaking Spanish and Catalan with developmental language disorder (DLD) during their primary education and to predict their academic outcomes using several processing skills assessed at the beginning of their schooling. To this end, we followed 28 children during their schooling (6–12 years of age). Participants were divided into two groups, one with DLD (n = 14) and a control group (n = 14) paired by age, gender, socio-economic status (SES), family language (L1), and classroom. All participants were assessed through different processing skills with the Spanish version of the NEPSY at the beginning of their schooling (age 6): attention (visual attention, auditory attention, and response set), phonological awareness, verbal short-term memory (sentence repetition, and narrative memory), access to language (semantic verbal fluency and rapid naming), and language comprehension (comprehension of verbal commands). At the end of primary education, schools reported the official academic marks at the 1st cycle (6–8 years), 2nd cycle (8–10 years) and 3rd cycle (10–12 years). Direct scores of the processing skills and academic results were used for statistical analyses. Results showed that children with DLD had more frequent grade retention, and their academic marks were significantly lower than those of their peers in all the cycles and for all academic subjects with a high language dependency (all except physical education and mathematics). Those subjects with lower language dependence did not show significant differences (physical education and mathematics). Rapid naming accounted for most of the variance of academic outcomes, followed by phonological awareness, and language comprehension when both groups were taken together. Only rapid naming accounted for academic results in the DLD group and phonological awareness did so for the control group. In sum, children with DLD experienced more academic difficulties during their primary education. Those children (with and without DLD) who experienced difficulties not only with rapid naming but also with phonological awareness and oral language comprehension at the beginning of their schooling showed a higher probability of academic failure.
Collapse
Affiliation(s)
- Eva Aguilar-Mediavilla
- Department of Applied Pedagogy and Educational Psychology, University of the Balearic Islands, Palma, Spain
| | - Lucía Buil-Legaz
- Department of Applied Pedagogy and Educational Psychology, University of the Balearic Islands, Palma, Spain
| | - Raül López-Penadés
- Department of Applied Pedagogy and Educational Psychology, University of the Balearic Islands, Palma, Spain
| | - Victor A Sanchez-Azanza
- Department of Applied Pedagogy and Educational Psychology, University of the Balearic Islands, Palma, Spain
| | - Daniel Adrover-Roig
- Department of Applied Pedagogy and Educational Psychology, University of the Balearic Islands, Palma, Spain
| |
Collapse
|
5
|
Usler ER, Walsh B. The Effects of Syntactic Complexity and Sentence Length on the Speech Motor Control of School-Age Children Who Stutter. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2018; 61:2157-2167. [PMID: 30128477 PMCID: PMC6195042 DOI: 10.1044/2018_jslhr-s-17-0435] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 04/30/2018] [Indexed: 05/12/2023]
Abstract
PURPOSE Early childhood stuttering is associated with atypical speech motor development. Compared with children who do not stutter (CWNS), the speech motor systems of school-age children who stutter (CWS) may also be particularly susceptible to breakdown under increased processing demands. The effects of increased syntactic complexity and sentence length on articulatory coordination were investigated. METHOD Kinematic, temporal, and behavioral indices of articulatory coordination were quantified for school-age CWS (n = 19) and CWNS (n = 18). Participants produced 4 sentences varying in syntactic complexity (simple declarative/complex declarative with a relative clause) and sentence length (short/long). Lip aperture variability (LAVar) served as a kinematic measure of interarticulatory consistency over repeated productions. Articulation rate (syllables per second) was also calculated as a related temporal measure. Finally, we computed accuracy and stuttering frequency percentages for each sentence to assess task performance. RESULTS Increased sentence length, but not syntactic complexity, increased LAVar in both groups. This effect was disproportionately greater for CWS compared with CWNS. No group differences were observed for articulation rate. CWS were also less accurate in their sentence productions than fluent peers and exhibited more instances of stuttering when processing demands associated with length and syntactic complexity increases. CONCLUSIONS The speech motor systems of school-age CWS appear to be particularly vulnerable to processing demands associated with increased sentence length, as evidenced by increased LAVar. Increasing the length and complexity of the sentence stimuli also resulted in reduced production accuracy and increased stuttering frequency. We discuss these findings within a motor control framework of speech production.
Collapse
Affiliation(s)
- Evan R Usler
- Department of Speech, Language, and Hearing Sciences, Boston University, MA
- Speech and Feeding Disorders Laboratory, MGH Institute of Health Professions, Boston, MA
| | - Bridget Walsh
- Department of Communicative Sciences and Disorders, Michigan State University, East Lansing
| |
Collapse
|
6
|
Kreindel E, Intraub H. Anticipatory scene representation in preschool children's recall and recognition memory. Dev Sci 2016; 20. [PMID: 27582346 DOI: 10.1111/desc.12444] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 03/23/2016] [Indexed: 11/26/2022]
Abstract
Behavioral and neuroscience research on boundary extension (false memory beyond the edges of a view of a scene) has provided new insights into the constructive nature of scene representation, and motivates questions about development. Early research with children (as young as 6-7 years) was consistent with boundary extension, but relied on an analysis of spatial errors in drawings which are open to alternative explanations (e.g. drawing ability). Experiment 1 replicated and extended prior drawing results with 4-5-year-olds and adults. In Experiment 2, a new, forced-choice immediate recognition memory test was implemented with the same children. On each trial, a card (photograph of a simple scene) was immediately replaced by a test card (identical view and either a closer or more wide-angle view) and participants indicated which one matched the original view. Error patterns supported boundary extension; identical photographs were more frequently rejected when the closer view was the original view, than vice versa. This asymmetry was not attributable to a selection bias (guessing tasks; Experiments 3-5). In Experiment 4, working memory load was increased by presenting more expansive views of more complex scenes. Again, children exhibited boundary extension, but now adults did not, unless stimulus duration was reduced to 5 s (limiting time to implement strategies; Experiment 5). We propose that like adults, children interpret photographs as views of places in the world; they extrapolate the anticipated continuation of the scene beyond the view and misattribute it to having been seen. Developmental differences in source attribution decision processes provide an explanation for the age-related differences observed.
Collapse
Affiliation(s)
- Erica Kreindel
- Department of Psychological and Brain Sciences, University of Delaware, USA
| | - Helene Intraub
- Department of Psychological and Brain Sciences, University of Delaware, USA
| |
Collapse
|
7
|
REFERENCES. Monogr Soc Res Child Dev 2016. [DOI: 10.1111/mono.12254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
8
|
Chekaf M, Cowan N, Mathy F. Chunk formation in immediate memory and how it relates to data compression. Cognition 2016; 155:96-107. [PMID: 27367593 DOI: 10.1016/j.cognition.2016.05.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 05/24/2016] [Accepted: 05/31/2016] [Indexed: 10/21/2022]
Abstract
This paper attempts to evaluate the capacity of immediate memory to cope with new situations in relation to the compressibility of information likely to allow the formation of chunks. We constructed a task in which untrained participants had to immediately recall sequences of stimuli with possible associations between them. Compressibility of information was used to measure the chunkability of each sequence on a single trial. Compressibility refers to the recoding of information in a more compact representation. Although compressibility has almost exclusively been used to study long-term memory, our theory suggests that a compression process relying on redundancies within the structure of the list materials can occur very rapidly in immediate memory. The results indicated a span of about three items when the list had no structure, but increased linearly as structure was added. The amount of information retained in immediate memory was maximal for the most compressible sequences, particularly when information was ordered in a way that facilitated the compression process. We discuss the role of immediate memory in the rapid formation of chunks made up of new associations that did not already exist in long-term memory, and we conclude that immediate memory is the starting place for the reorganization of information.
Collapse
|
9
|
|
10
|
Mathy F, Fartoukh M, Gauvrit N, Guida A. Developmental Abilities to Form Chunks in Immediate Memory and Its Non-Relationship to Span Development. Front Psychol 2016; 7:201. [PMID: 26941675 PMCID: PMC4763062 DOI: 10.3389/fpsyg.2016.00201] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/02/2016] [Indexed: 12/02/2022] Open
Abstract
Both adults and children –by the time they are 2–3 years old– have a general ability to recode information to increase memory efficiency. This paper aims to evaluate the ability of untrained children aged 6–10 years old to deploy such a recoding process in immediate memory. A large sample of 374 children were given a task of immediate serial report based on SIMON®, a classic memory game made of four colored buttons (red, green, yellow, blue) requiring players to reproduce a sequence of colors within which repetitions eventually occur. It was hypothesized that a primitive ability across all ages (since theoretically already available in toddlers) to detect redundancies allows the span to increase whenever information can be recoded on the fly. The chunkable condition prompted the formation of chunks based on the perceived structure of color repetition within to-be-recalled sequences of colors. Our result shows a similar linear improvement of memory span with age for both chunkable and non-chunkable conditions. The amount of information retained in immediate memory systematically increased for the groupable sequences across all age groups, independently of the average age-group span that was measured on sequences that contained fewer repetitions. This result shows that chunking gives young children an equal benefit as older children. We discuss the role of recoding in the expansion of capacity in immediate memory and the potential role of data compression in the formation of chunks in long-term memory.
Collapse
Affiliation(s)
- Fabien Mathy
- Bases Corpus Langage UMR 7320 CNRS, Université Nice Sophia-Antipolis Nice, France
| | - Michael Fartoukh
- Bases Corpus Langage UMR 7320 CNRS, Université Nice Sophia-Antipolis Nice, France
| | | | - Alessandro Guida
- Centre de Recherches en Psychologie, Cognition et Communication, Université Rennes II Rennes, France
| |
Collapse
|
11
|
Smith E, Jarrold C. Grouping, semantic relation and imagery effects in individuals with Down syndrome. RESEARCH IN DEVELOPMENTAL DISABILITIES 2014; 35:3162-3174. [PMID: 25151606 DOI: 10.1016/j.ridd.2014.07.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 07/24/2014] [Accepted: 07/29/2014] [Indexed: 06/03/2023]
Abstract
Down syndrome (DS) is associated with a specific verbal short-term memory (STM) deficit. This study explored the effects of grouping, semantic relations and visual presentation upon verbal STM recall performance in a group of 15 individuals with DS and 15 vocabulary-matched typically developing (TD) children. Participants were presented with memoranda in either a temporally grouped schedule, such that items were grouped as pairs, or in an equally spaced presentation schedule. The two items constituting each pair were either semantically related or unrelated. Performance across these conditions was compared in verbal or verbal plus visual presentation modes. Significant memory recall benefits were observed across populations as a result of temporal grouping, semantic relations and verbal and visual combined presentation. However, a reduced benefit of semantic relation in the DS group compared to the TD group indicated that those with DS were less influenced by LTM relational knowledge. In addition, those with DS only experienced a grouping benefit during verbal and visual combined presentation, in contrast to the TD group who experienced grouping benefits throughout. This indicates that individuals with DS are poorer at encoding temporal context for purely verbal memoranda. These findings were replicated in a follow-up experiment, aimed at aligning baseline performance in the two populations. This study provides encouraging evidence that, despite their difficulties in some areas, individuals with DS can benefit from the use of grouping and LTM knowledge to assist their verbal STM performance under certain circumstances.
Collapse
|
12
|
Kibbe MM, Feigenson L. Developmental origins of recoding and decoding in memory. Cogn Psychol 2014; 75:55-79. [PMID: 25195153 DOI: 10.1016/j.cogpsych.2014.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/31/2014] [Accepted: 08/01/2014] [Indexed: 11/19/2022]
Abstract
Working memory is severely limited in both adults and children, but one way that adults can overcome this limit is through the process of recoding. Recoding happens when representations of individual items are chunked together into a higher order representation, and the chunk is assigned a label. That label can then be decoded to retrieve the individual items from long-term memory. Whereas this ability has been extensively studied in adults (as, for example, in classic studies of memory in chess), little is known about recoding's developmental origins. Here we asked whether 2- to 3-year-old children also can recode-that is, can they restructure representations of individual objects into a higher order chunk, assign this new representation a verbal label, and then later decode the label to retrieve the represented individuals from memory. In Experiments 1 and 2, we showed children identical blocks that could be connected to make tools. Children learned a novel name for a tool that could be built from two blocks, and for a tool that could be built from three blocks. Later we told children that one of the tools was hidden in a box, with no visual information provided. Children were allowed to search the box and retrieve varying numbers of blocks. Critically, the retrieved blocks were identical and unconnected, so the only way children could know whether any blocks remained was by using the verbal label to recall how many objects comprised each tool (or chunk). We found that even children who could not yet count adjusted their searching of the box depending on the label they had heard. This suggests that they had recoded representations of individual blocks into higher-order chunks, attached labels to the chunks, and then later decoded the labels to infer how many blocks were hidden. In Experiments 3 and 4 we asked whether recoding also can expand the number of individual objects children could remember, as in the classic studies with adults. We found that when no information was provided to support recoding, children showed the standard failure to remember more than three hidden objects at once. But when provided recoding information, children successfully represented up to five individual objects in the box, thereby overcoming typical working memory limits. These results are the first demonstration of recoding by young children; we close by discussing their implications for understanding the structure of memory throughout the lifespan.
Collapse
Affiliation(s)
- Melissa M Kibbe
- Department of Psychological and Brain Sciences, Boston University, 64 Cummington Mall, Boston, MA 02215, USA; Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA.
| | - Lisa Feigenson
- Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA.
| |
Collapse
|
13
|
Korkman M, Lahti-Nuuttila P, Laasonen M, Kemp SL, Holdnack J. Neurocognitive development in 5- to 16-year-old North American children: A cross-sectional study. Child Neuropsychol 2013; 19:516-39. [DOI: 10.1080/09297049.2012.705822] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
14
|
Simmering VR, Perone S. Working memory capacity as a dynamic process. Front Psychol 2013; 3:567. [PMID: 23335902 PMCID: PMC3538562 DOI: 10.3389/fpsyg.2012.00567] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 11/30/2012] [Indexed: 11/13/2022] Open
Abstract
A well-known characteristic of working memory (WM) is its limited capacity. The source of such limitations, however, is a continued point of debate. Developmental research is positioned to address this debate by jointly identifying the source(s) of limitations and the mechanism(s) underlying capacity increases. Here we provide a cross-domain survey of studies and theories of WM capacity development, which reveals a complex picture: dozens of studies from 50 papers show nearly universal increases in capacity estimates with age, but marked variation across studies, tasks, and domains. We argue that the full pattern of performance cannot be captured through traditional approaches emphasizing single causes, or even multiple separable causes, underlying capacity development. Rather, we consider WM capacity as a dynamic process that emerges from a unified cognitive system flexibly adapting to the context and demands of each task. We conclude by enumerating specific challenges for researchers and theorists that will need to be met in order to move our understanding forward.
Collapse
Affiliation(s)
| | - Sammy Perone
- Department of Psychology, University of Iowa and Delta CenterIowa City, IA, USA
| |
Collapse
|
15
|
Kapikian A, Briscoe J. Semantic binding, not attentional control, generates coherent global structure in children's narrative memory. JOURNAL OF COGNITIVE PSYCHOLOGY 2012. [DOI: 10.1080/20445911.2012.690554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
16
|
What's magic about magic numbers? Chunking and data compression in short-term memory. Cognition 2011; 122:346-62. [PMID: 22176752 DOI: 10.1016/j.cognition.2011.11.003] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 10/25/2011] [Accepted: 11/02/2011] [Indexed: 11/22/2022]
Abstract
Short term memory is famously limited in capacity to Miller's (1956) magic number 7±2-or, in many more recent studies, about 4±1 "chunks" of information. But the definition of "chunk" in this context has never been clear, referring only to a set of items that are treated collectively as a single unit. We propose a new more quantitatively precise conception of chunk derived from the notion of Kolmogorov complexity and compressibility: a chunk is a unit in a maximally compressed code. We present a series of experiments in which we manipulated the compressibility of stimulus sequences by introducing sequential patterns of variable length. Our subjects' measured digit span (raw short term memory capacity) consistently depended on the length of the pattern after compression, that is, the number of distinct sequences it contained. The true limit appears to be about 3 or 4 distinct chunks, consistent with many modern studies, but also equivalent to about 7 uncompressed items of typical compressibility, consistent with Miller's famous magical number.
Collapse
|
17
|
Cowan N, AuBuchon AM, Gilchrist AL, Ricker TJ, Saults JS. Age differences in visual working memory capacity: not based on encoding limitations. Dev Sci 2011; 14:1066-74. [PMID: 21884322 DOI: 10.1111/j.1467-7687.2011.01060.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Why does visual working memory performance increase with age in childhood? One recent study (Cowan et al., 2010b) 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.
Collapse
Affiliation(s)
- Nelson Cowan
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, USA.
| | | | | | | | | |
Collapse
|