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WORKING MEMORY IN 5-TO-7 YEAR-OLD CHILDREN:ITS STRUCTURE AND RELATIONSHIP TO FLUID INTELLIGENCECaroline HORNUNGMartin BRUNNERRobert REUTERRomain MARTIN

15th European Conference on Developmental Psychology24th August 2011 - Bergen, Norway

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Part of Caroline HORNUNG’s PhD thesis

Part of a larger study on the development of mathematical abilities in early primary school and potential predictors in kindergarten

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OUTLINEAIMSCONCEPTS

Working MemoryFluid Intelligence

METHODRESULTSCONCLUSIONS

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AIMSContrast different STRUCTURAL MODELS of WORKING MEMORY in CHILDREN

Study the RELATIONSHIP between WORKING MEMORY components and FLUID INTELLIGENCE in CHILDREN

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WORKING MEMORY (WM)Concept used to explain our capacity to store and process information, to inhibit irrelevant information, and to take incremental steps to achieve certain goals.

WM is thought of as a complex cognitive system of limited capacity.

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STRUCTURE OF WMShort-term storage component, holds information briefly (Short-Term Memory)

Non-storage component, responsible for further processing, generally referring to executive attention control

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MEASURING WMShort-term storage component: simple span tasks, require storage and direct recall of information

Processing component: complex span tasks, require simultaneous storage and processing of information

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WM IN CHILDREN•Most previous studies focused on adults•General consensus that WM capacities develop during childhood•Little is known about structure of WM in children•NEED to test and contrast existing adult models of WM in children

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MODELS OF WM IN CHILDREN1.Unitary Model: STM = WM2.Sequential Model: STM <> WM3.Two Domain-Specific Components: Verbal and Visuo-Spatial Storage Systems4.Baddeley’s WM Model: Central Executive, Verbal and Visuo-Spatial Storage Systems (storage = attention-free)5.Cowan’s WM Model: WM capacity = core storage capacity, short-term storage = focus of attention = active long-term memory representations; involves a domain-general component AND two domain-specific components6. Unsworth & Engle’s WM Model: separates storage from executive attention control processes

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MODELS OF WM IN CHILDREN

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FLUID INTELLIGENCE (GF)Concept used to explain our capacity to perform abstract reasoning, to adapt to novel complex situations.

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WM & GF IN CHILDREN•In adults, WM is strongly linked to GF•Higher order thinking skills are highly depend on storage and processing of information•Mixed results about WM & GF in children•NEED to directly contrast existing adult models of WM & GF in children

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MODELS OF WM & GF IN CHILDREN

1.Unitary Model: single general WM component <=> GF2.Sequential Model: STM & WM <=> GF3.Two Domain-Specific Components: Verbal and Visuo-Spatial Storage Systems <=> GF4.Baddeley’s WM Model: Central Executive, Verbal and Visuo-Spatial Storage Systems <=> GF5.Cowan’s WM Model: short-term storage as a domain-general component AND two domain-/task specific components6.Unsworth & Engle’s WM Model: Storage vs. Non-Storage VERBAL processes: common variance factor = short-term storage vs. residual = executive attention control & VISUO-SPATIAL processes

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METHODParticipantsProcedureMeasuresStatistical analyses: SEM

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METHODParticipants•161 children, 78 girls & 83 boys•from 7 preschools in Luxembourg-City and suburbs•tested 5 months before entering first grade•mean age: 74.8 months (SD=3.80, range=67-86)•typical multilingual situation (36% Lux.; 40.4% Port.)•training examples revealed that all children seemed to understand the task instructions in Luxembourgish•diverse socio-economic backgrounds

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METHODProcedure•two separate test sessions at an interval of 3 hours to 4 days•tested individually in a quiet room at their preschool•most session in the morning•brief story to make children feel at ease•general instructions•several training trials (until instructions understood)•no performance-contingent feedback during test sessions•general encouragement to proceed, independent of performance

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METHODMeasures•Tasks based on prior research and on discussions with colleagues and preschool teachers•Instructions and stimuli translated into Luxembourgish•Verbal span tasks were pre-tested on 45 children, 4-6 years old•Verbal span tasks•Visuo-spatial span tasks•GF task

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METHODMeasuresVerbal simple span tasks•Digit recall•Nonword recallVerbal complex span tasks•Backward digit recall•Backward color recallVisuo-spatial span tasks•Location span task WITH visual grid•Location span task WITHOUT visual grid(requires additional executive attention control)

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METHODMeasuresVerbal simple span tasks•Digit recall•Nonword recallVerbal complex span tasks•Backward digit recall•Backward color recallVisuo-spatial span tasks•Location span task WITH visual grid•Location span task WITHOUT visual grid(requires additional executive attention control)

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METHOD

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METHOD

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Raven’s Coloured Progressive Matrices:testing figural reasoning

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METHODStructural Equation Models (SEM)They offer several advantages relative to traditional analysis with correlational models:

• First, according to Bollen (1989), the variance common to a set of related measures gives a more coherent representation of an underlying theoretical construct than any single measure of a task as task-specific variance is not represented in the variance of the latent construct (given that a broad range of measures is applied).• Second, latent variables are free of measurement error. It thus provides an unbiased estimate of the relationships between cognitive constructs (cf. Cohen, Cohen, West, & Aiken, 2003).

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RESULTSStructure of WM components in children

Relationship between WM and GF

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RESULTSStructure of WM components in children

Relationship between WM and GF

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RESULTSStructure of WM components in children

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RESULTSStructure of WM components in children

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RESULTSStructure of WM components in children

Relationship between WM and GF

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RESULTSRelationship between WM and GF

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RESULTSRelationship between WM and GF

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RESULTS

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CONCLUSIONS (WM)Models 4, 5 & 6 suggest that children, like adults, draw on storage and non-storage processes when completing memory-span tasks

Model 4: task impurity problemModels 5 & 6: emphasis on domain-general processes supporting storage(“in the focus of attention”)

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CONCLUSIONS (WM & GF)STORAGE and NON-STORAGE components are RELATED to FLUID INTELLIGENCE

SHORT-TERM STORAGE CAPACITY predominantly EXPLAINS their RELATION in CHILDREN

Short-Term Storage is an ATTENTION-DEMANDING PROCESS (COWAN et al., 2006: attention for storage and attention for processing)

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CONCLUSIONS (WM & GF)Simple span tasks are equivalently good indicators of children’s core storage capacity as complex span tasks.

This capacity is essential for reasoning and problem-solving and explains individual differences in fluid intelligence.

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Further details in our recently published paper:

Hornung, C., Brunner, M., Reuter, R. A. P., & Martin, R. (2011). Children’s working memory: Its structure and relationship to fluid intelligence. Intelligence, 39(4), 210-221. doi:16/j.intell.2011.03.002

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for advanced questions, please email caroline.hornung@gmail.com

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THANK YOUFOR YOUR

ATTENTION!

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ABSTRACT

Working memory (WM) has been predominantly studied in adults. The insights provided by these studies have led to the development of competing theories on the structure of WM and conflicting conclusions on how strongly WM components are related to higher order thinking skills such as fluid intelligence (GF). However, it remains unclear whether and to what extent the theories and findings derived from adult data generalize to children. The purpose of the present study was therefore to investigate WM in 5-to-7-year-old children (N = 161). Specifically, we examined different structural models of WM and how its components, as defined in these models, are related to GF. Our results suggest that children draw on both domain-general and domain-specific processes when performing memory span. Crucially, our findings indicate that domain-general processes result in a core storage capacity that primarily explains the relationship between WM and GF. Based on these observations we discuss the theoretical and methodological issues that arise when children’s WM is investigated.