Executive functions

Executive functions

37-975-01

Challenges to Language Acquisition: Bilingualism and Language Impairment

Dr. Sharon Armon-LotemBar Ilan University

Domain General Accounts (Not language specific

Procedural Deficit Hypothesis (PDH) Processing limitations in Executive

Functions (EF)

Procedural Deficit Hypothesis (PDH)Ullman, M.T. & Pierpont, E.I. 2005. Specific Language Impairment is not Specific to Language: The Procedural Deficit Hypothesis. Cortex 41, 399-433.

"SLI can be largely explained by the abnormal development of brain structures that constitute the procedural memory system.”

Procedural memory: “mental grammar”, syntax, some morphology

Declarative memory: “mental lexicon”, vocabulary, idioms, irregular past-tense forms

Procedural Memory System: Definition

Brain system involved in “procedural memory”

Learning new and controlling established motor and cognitive skills, habits, and other procedures

E.g. typing, riding a bike, skilled game playing

Aspects of rule-learning Learning and performing skills involving sequences

Includes system involved in learning, representation, and use of procedural memory

Procedural System: Characteristics

Gradual acquisition of procedures

Learning occurs with practice, over time

Rapid, automatic application

“Implicit Memory System”

Procedural Deficit Hypothesis

Problems with different structures in the PS will result in different types of impairment

Grammatical and lexical retrieval deficits are strongly linked to dysfunctions of the basal ganglia (BG), esp. caudate nucleus, and of the frontal cortex, esp. Broca’s area

PDH: Empirical Evidence

Studies of neural correlates of SLI Anatomical studies

SLI linked to abnormalities of frontal cortex and basal ganglia SLI linked to abnormal cerebellar structures Atypical asymmetry and other abnormalities of declarative system

could reflect connectivity or compensation

Event-related potential studies SLI show atypical ERPs when presented with function words, but not

content words Function words elicit ERPs similar to content words, consistent with

declarative system compensation

PDH: Behavioral Evidence

Predictions of PDHImpairment in rule-governed operations No impairment in memorized

idiosyncratic knowledge (lexicon)Possible compensation for

grammatical/procedural deficit with increased reliance on lexical/declarative memory

Grammatical Profile of SLI

Compensatory shift between PS and DSPeople with SLI use declarative memory to

memorize complex forms and/or explicit rules Disproportionate reliance on high-frequency

phrases No difference between regular and irregular past-

tense forms Impairment in production of past-tense forms, but

not judgment

Processing limitations in Executive Functions (EF) Im-Bolter, N., Johnson, J., & Pascual-Leone, J.

(2006). Processing limitations in children with specific language impairment: The role of executive function. Child Development, 6, 1822-1841.

Kohnert, K., & Windsor, J. (2004). The search for common ground: Part II. Nonlinguistic performance by linguistically diverse learners. Journal of Speech, Language, and Hearing Research, 47, 891-903.

What are Executive Functions?

Goal-oriented, efficient, and adaptive social behavior.

Capacity to think ahead, suppress impulses,temporarily hold information, and think flexibly.

Needed in carrying out a task that is complicatedor novel, requiring sustained conscious attention (Miller & Cohen, 2001).

Essential in everyday behavior

From: Profiles of Executive Function in Developmental and Acquired Disorders: Measurement and Classification, Mariëtte Huizinga, Ph.D., COST Action IS0804

Where does it happen?

Difficulties in executive function

Decision making Planning Cognitive flexibility Inhibition “Monitoring” of one’s own behavior


Executive functions are separable(but not independent)

Three ‘core’ executive functions (Miyake et al. 2000):

Updating and monitoring of working memoryrepresentations;

Shifting between tasks or mental sets; Inhibition of dominant or pre-potent responses.




Im-Bolter, N., Johnson, J., & Pascual-Leone, J. (2006). Processing limitations in children with specific language impairment: The role of executive function.

M capacity - Mental attentional capacity. The maximal number of mental schemes, not directly activated by the here-and-now situation, that a person can actively hold in mind at any one time.

Aim & Hypothesis (p.1826) “To investigate M capacity and executive function in

children with and without SLI to determine whether children with SLI have a general processing deficit or deficits in certain executive processes, and the extent to which these processes are related to language competence”.

“To examine whether potential impairments in general executive processes mediated the relationship between activatory (M) and inhibitory (I) processing resources and language competence”.

“If children with SLI truly have limited processing capacity that is domain general, compared with their chronological age peers, they should perform at a lower stage on all M-measures, regardless of specific domain (i.e., visual vs. verbal).”

Participants

Mental Attentional Capacity (M capacity) - Measures and results

A 2 X 3 (M measure) ANOVA with repeated measures on the second factor indicated a main effect for group, F(1, 87)=63.67, p<0.001, and an interaction, F(2, 174)=3.94, p<0.05, but no main effect for M measure, F(2, 174)=0.28, p>0.50.

A 2 X 3 (MAM subtest) ANOVAwith repeated measures on the second factor results in main effects for group, F(1, 87)=40.82, p<0.0001, and MAM subtest, F(2, 174)=250.97, p<0.0001, but no interaction,F(2, 174)=0.76, p>0.45.

Performance for all children decreased as interference increased

The SLI group had lower scores on all three M measures compared with the NL group.

The SLI group performed at a similar level across all three M measures.

>> children with SLI have limited processing capacity that is domain general rather than domain specific.

The strength of the group effect was greater for the language/verbal M measures, however, and this suggests that there may be some domain-specific factors (e.g., linguistic executives) that affect verbal processing to a greater degree.

The SLI group performed more poorly than the NL group on tasks of updating and inhibition

The two groups did not differ on tasks of shifting, however.

(a) level of language performance is directly related to the amount of M capacity that one can mobilize;

(b) recentration (updating) but not decentration (shifting) is related to efficient use of processing resources with respect to language

(c) interruption (inhibition) does not have a direct relationship with language competence, but may be related to language performance via its dialectical relationship with M capacity.

These results provide evidence for the hypothesis that deficits in updating and inhibition ability affect efficient use of resources for activating relevant information in language tasks.

Kohnert, K., & Windsor, J. (2004). The search for common ground: Part II. Nonlinguistic performance by linguistically diverse learners

ParticipantsNAge

EO5010;7 (1;10)

LI2610;6 (1;7)

BI229;9 (1;5)

*EO<LIEO<LIBI<LIBI<LI *BI<LIBI<LI

EO=BIEO=BI EO=BI EO=BI*EO<LI *EO<LI

* p<0.05

Subtle inefficiency in basic non-linguistic processing of children with SLI

Bialystok, E., & Martin, M. (2004). Attention and inhibition in bilingual children: Evidence from the dimensional change card sort task. Developmental Science, 7, 325-339. HEBA 10/1

Prior, A., & MacWhinney, B. (2010). A bilingual advantage in task-switching. Bilingualism: Language and Cognition, 00(0), 1-10. DANIEL 10/1

Language Proficiency and Executive Control in Bilingual Children with TLD and with SLI

Peri Iluz-Cohen

Bar Ilan University

Ramat-Gan, Israel

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Executive functions