Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
First steps in Language First steps in Language
Acquisition: Evidence from Acquisition: Evidence from
ERPsERPs
Angela D. Friederici
Max Planck Institute for Human Cognitive and Brain SciencesLeipzig, Germany
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
• High temporal resolution as it measures the brain‘s activity millisecond by millisecond.
• No behavioral reaction necessary.
Method of Event Related Potential (ERP)
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
ERP method
AUDITORY EVENT-RELATED POTENTIAL-6 µV
+6 µV
Time (ms)STIMULUSONSET
one secS S S S
ONGOING EEG
ELAN
P200
N400
P600
AUDITORYSTIMULUS
(S)
Amplifier
Signalaverager
200 400 600 800 1000
ERP method
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Infants' first Steps into Language are Based on Prosodic Information
The identification of syntactic phrase boundaries is eased by prosodic information as each intonational phrase boundary is a syntactic phrase boundary.
The identification of word boundaries (word onset and offset) is eased by information about word stress. In a language like English or German, in which the stress of two syllable words lies predominantly on the first syllable, stress information can certainly help to identify word onsets.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Syllable Length and Word Stress Discrimination
• Word stress in German is predominantly (› 90% of two syllable words) on the first syllable.
• Word stress is indicated by a number of acoustic parameters with syllable duration (length) being the most prominent one.
• In order to investigate the infants' ability to discriminate words stressed on the first syllable versus words stressed on the second syllable we decided to initially investigate the infants' ability to discriminate between a long and a short syllable. We did so by using the MMN paradigm.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Mismatch Negativity (MMN)
... is a pre-attentive response.
... is elicited by any discriminablechange in repetitive auditory stimulation (oddball design):
... is the result of deviance detection.
sta devstasta sta sta
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Experiment 1Discrimination of Syllables of Different Duration
/ba:/ 341 ms
/ba/ 202 ms
Standard 5/6
Deviant 1/6
2. Block ba ba ba ba baa ba ba ba baa ba ba ...
1. Block baa baa baa baa ba baa baa baa ba ...
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Adults: Difference wave between Deviant-Standard
The Mismatch Negativity MMN
Source: Friedrich, Weber & Friederici, Psychophysiology, 2004
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
ERP and difference waves (Deviant-Standard)of 2-month-old infants
Experiment 1Discrimination of Syllables of Different Duration
Source: Friederici, Friedrich & Weber, NeuroReport, 2002
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Difference waves for long syllable in 2-month- old infants and adults
Experiment 1Discrimination of Syllables of Different Duration
Source: Friederici et al., NeuroReport, 2002; Friederici et al., 2004
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Summary Experiment 1
• Infants by the age of 2 months are able to discriminate long syllables from short syllables.
• Infants more easily discriminate a long syllable in a stream of short syllables than vice versa.
• Infants show a positivity as MMN response.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
One of the hypotheses we persued was the notion that a major underlying cause of Specific Language Impairment (SLI) is a deficiency in processing prosodic information.
If so, infants with risk for SLI may be deficient already in discriminating long from short syllables at the age of 2 months.
Hypothesis for SLI
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Experiment 1b
Source: Friedrich, Weber & Friederici, Psychophysiology, 2004
Difference waves for 2-month-olds with and without risk for SLI
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Summary Experiment 1b
Infants with risk for SLI differ from those with no risk already at the age of 2 months in their perceptual ERP parameters for duration discrimination.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Experiment 2Discrimination of Different Stress Patterns
/ba:ba/ 750 ms
/baba:/ 750 ms
Standard 5/6
Deviant 1/6
1. Block baaba baaba baaba babaa baaba baaba
2. Block babaa babaa babaa babaa baaba babaa
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Difference waves 4- and 5-month-old infants
Experiment 2Discrimination of Different Stress Patterns
Source: Weber, Hahne, Friedrich & Friederici, Cognitive Brain Research, 2004
MMN
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Summary Experiment 2
• Infants by the age of 5 months are able to discriminate word stress of two syllable words.
• Discrimination is evident as indicated by MMN for the trochaic pattern (stress on first syllable) which is the predominant pattern in German.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Difference waves 5-month-old infants
Experiment 2bDiscrimination of Different Stress Patterns
Source: Weber, Hahne, Friedrich & Friederici, Cognitive Brain Research, 2004
MMN
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Summary Experiment 2b
Infants with risk for SLI demonstrate a reduced discrimination ability for the language-specific trochaic pattern at the age of 5 months.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Stress Pattern DiscriminationNovel Analysis: 5-month-olds
Source: Weber, Hahne, Friedrich & Friederici, Cognitive Brain Research, 2004
At-risk group classification based on word production at
2 years.
MMN
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Processing Intonational Phrase Boundaries
As each intonational phrase boundary is a syntactic phrase boundary, the identification of an intonational phrase boundary provides an easy entrance into the syntax of a given language.
How can we investigate this identification process using ERPs?
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Prosodically correct conditions
(A) correct: Late Closure[IP1 Peter verspricht Anna zu ARBEITEN ] # [IP2 und ...
('Peter promises Anna to work and ...
(B) correct: Early Closure[IP1 Peter verspricht ] # [IP2 ANNA zu entlasten ] [IP3 und ...
('Peter promises to support Anna and ...
Experiment 3
Source: Steinhauer, Alter & Friederici, Nature Neuroscience, 1999
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Source: Steinhauer, Alter & Friederici, Nature Neuroscience, 1999
Effect of Intonational Phrase BoundarySpoken sentences: Adults
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Spoken Sentences: 8-month-old Infants
Source: Pannekamp, Weber & Friederici, NeuroReport, in press
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Summary Experiment 3
Infants by the age of 8 months show a brain response to intonational phrase boundary similar to that of adults.
adults 8-month-old infants
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
2 8
MMN
5
Development of Prosodic Perception
basic mechanisms underlying the identification of word
boundaries
discrimination of
syllable duration
CPS
basic mechanisms underlying the identification of
intonational (syntactic) boundaries
sensitivity to intonational phrase
boundary
discrimination word stress pattern
Months of ageBirth
ERP-
correlates
Source: Friederici, Trends in Cognitive Sciences, 2005
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
To understand mechanisms of early word learning, it is important to know whether the infant’s brain acts in an adult-like manner when processing meaningful words in meaningful contexts.
The N400, a negative component in the ERP of adults, reflects neural mechanisms of semantic integration into context.
Processing Lexical-Semantic Information
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
In the present study, we investigated whether the neural mechanisms observed for adults are already working during early language acquisition when infants know only a few words.
Experiment 4: Lexical-Semantic Processing
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Using a picture-word design we recorded the ERP response of 12-, 14- and 19-month-old infants on slowly spoken basic level words. While infants were looking at sequentially presented pictures they were acoustically presented with words that were either congruous or incongruous to the picture contents.
Experiment 4: Lexical-Semantic Processing
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
congruous
incongruous
Lexical-Semantic Processing Paradigm
“Ball” (ball)
“Ente” (duck)
“Lampe” (lamp)
“Schaf” (sheep) time
incongruous
congruous
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Adapted from Friederici,Trends in Cognitive Sciences, 2005
Adults
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2004
ERP of 19-month-old infants
Experiment 4: Lexical-Semantic Processing
N400
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Experiment 4: Lexical-Semantic Processing
Source: Friedrich & Friederici, Psychophysiology, 2005
ERP of 19-month-old infants: normals and at riskrisk (low scores on word & sentence production)
Normals At risk
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Adapted from Friederici,Trends in Cognitive Sciences, 2005
19-month-olds Adults
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Adapted from Friederici,Trends in Cognitive Sciences, 2005
14-month-olds 19-month-olds Adults
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Adapted from Friederici,Trends in Cognitive Sciences, 2005
12-month-olds 14-month-olds 19-month-olds Adults
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
400 – 700 ms 400 – 700 ms 400 – 700 ms
12-month-olds 14-month-olds 19-month-olds
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
ERP of 12-month-old infants
Experiment 4: Lexical-Semantic Processing
Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2005
early neg.
early neg.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Summary Experiment 4
• In our study, developmental changes in the early time range reflect increased familiarity with the presented words. The early negativity for congruous words in 12-month-old infants is interpreted as facilitation of phonological processing by lexical priming.
• The later centro-parietal negativity for incongruous words in 14- and 19-month-old infants is regarded as infant N400.
Early starting ERP differences in the infants’ temporal brain region have previously been linked to processing differences between known and unknown words (Mills et al., 1993).
Lexical-Semantic Processing
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Conclusion Experiment 4
The occurrence of a phonological-lexical priming effect in both age groups implies that not only 14-, but also 12-month-old infants already create lexical expectations from picture contents. This result suggests the existence of some lexical-semantic knowledge even in 12-month-old infants. Infants at that age, however, do not display a N400 semantic incongruity effect that is present in 14-month-old infants. From that we conclude that N400 maturates during the first half of the second year of life.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
months of age
2
CPSMMN
Birth 4 6 8
Identification of word boundaries
Identification of
intonational boundaries
Discrimination
of phonemes
Discrimination
word stresspattern
Sensitivity tointonational
phrase boundary
Adapted from Friederici, Trends in Cognitive Sciences, 2005
ERP
correlates
Developmental stages
Months of age
53 7
Development of Auditory Language PerceptionBasic stages and ERP correlates
12
Lexical processing
Lexical semantics
Lexical form
N400
14
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
months of age
2
CPSMMN
Birth 4 6 8
Identification of word boundaries
Identification of
intonational boundaries
Discrimination
of phonemes
Discrimination
word stresspattern
Sensitivity tointonational
phrase boundary
Adapted from Friederici, Trends in Cognitive Sciences, 2005
ERP
correlates
Developmental stages
Months of age
53 7
Development of Auditory Language PerceptionBasic stages and ERP correlates
12
Lexical processing
Lexical semantics
Lexical form
N400
14
Sentence processing
Selectionalrestrictionof verbs
Localphrase
structurebuilding
ELAN-P600
19 32
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Manuela Friedrich
Anja Hahne
Birgit Herold
Claudia Männel
Regine Oberecker
Ann Pannekamp
Christiane Weber
MAXPLANCK
INSTITUTE
FOR
LEIPZIG
HUMANCOGNITIVE AND BRAIN SCIENCES
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Experiment 5: Semantic Processes in Sentences
The next question is:
Do infants at that age also process semantic relations in sentential context?
Experiment 5 examines this question.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Semantic Violation
incorrect:
"Das Lineal wurde gefüttert"
"The ruler was fed"
correct:
"Das Baby wurde gefüttert"
"The baby was fed"
correctincorrect
CZ
N400Cz-5
5
µV
0 0.5 1 sec
semantic violation
Source: Hahne & Friederici, Cognitive Brain Research, 2002
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Stimulus Material
correct Die Katze trinkt die
Milch. The cat drinks the milk.
semantically incorrect Die Katze trinkt den
Ball. The cat drinks the ball.
Source: Friedrich & Friederici, NeuroReport, 2005
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2004
N400
Experiment 5: ERP of 24-month-olds
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Experiment 5: ERP of 19-month-olds
Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2004
N400
2607 Berlin IACL 2005
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Conclusion Experiment 5
The data show that children at the age of 19 months can process semantic relations between words in a sentence quite similar to adults.
The N400 effect, however, is longer lasting than in adults. As the N400 is taken to reflect integration difficulties, these data suggest that integration processes take longer in young children compared to adults.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
In adult syntactic processing ERP studies, the ELAN has been interpreted to reflect highly automatic phrase structure building processes, whereas the P600 is taken to reflect processes of syntactic integration (e.g. Hahne & Friederici, 1999).
If so, the P600 should be present earlier than the ELAN which was shown in 6- to 13-year-old children for syntactic violations in passive sentences (Hahne, Eckstein & Friederici, 2003).
Processing Syntactic Information
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
incorrect:
"Die Bluse wurde am gebügelt."
"The blouse was on ironed."
correct:
"Das Hemd wurde gebügelt."
"The shirt was ironed."
correctincorrect
F7
Source: Hahne & Friederici, Cognitive Brain Research, 2002
-5
5
µV
0 0.5 1 sec
F7ELAN
-5
5
µV
0 0.5 1 sec
Pz
P600PZ
Syntactic Violation
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Experiment 6 investigates at what age we can detect syntax-related ERP components. In this experiment syntactic violations were realized in simple active sentences.
Experiment 6: Syntactic Processing
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Stimulus Material
correct Der Löwe brüllt.The lion roars.
syntactically incorrect Der Löwe im brüllt.The lion in the roars.
correct filler item Der Löwe im Zoo brüllt.The lion in the zoo roars.
Source: Oberecker, Friedrich & Friederici, Journal of Cognitive Neuroscience, 2005
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
ELAN
P600
Experiment 6: Syntax adults
Source: Oberecker, Friedrich & Friederici, Journal of Cognitive Neuroscience, 2005
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Source: Oberecker, Friedrich & Friederici, Journal of Cognitive Neuroscience, 2005
ELAN
P600
Experiment 6: Syntax 32-month-old children
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Source: Oberecker & Friederici, submitted
P600
Experiment 6: Syntax 24-month-old children
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
P600
ELAN
P600
ELAN
P600
24-month-old children
32-month-old children
Adults
-10 µV
0.8 1.6
s
10
-10 µV
0.8 1.6
s
10
-5 µV
0.8 1.6
s
5
correctincorrect
correctincorrect
correctincorrect
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Conclusion Experiment 6
The data presented show for the first time that the infant‘s brain is sensitive to phrase structure violations in auditorily presented sentences already at the age of 2.5 years. Their ERP pattern reflects initial processes of structure building (ELAN) as well as late processes of syntactic integration difficulty (P600).
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Experiment 7: Syntax 32-month-olds at risk
Source: Oberecker & Friederici, in preparation
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
P600
ELAN
P600
No risk24-month-olds
No risk32-month-olds
-10 µV
0.8 1.6
s
10
-10 µV
0.8 1.6
s
10
-15 µV
0.8 1.6
s
15
correctincorrect
correctincorrect
correctincorrect
Risk32-month-olds
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Conclusion Experiment 7
Children with risk for SLI do not demonstrate an ELAN-P600 pattern at the age of 32 months.
This suggests that children classified at risk for SLI are delayed in their syntactic processing abilities, not only with respect to initial on-line syntactic structure building, but also with respect to late processes of syntactic integration.
Max Planck Institute for Human Cognitive and Brain SciencesTrieste, 07.05.2006
Processing Phonotactically legal and illegal Pseudowords
Source: Friedrich & Friederici, Psychophysiology, 2005
ERP of 19-month-old infants: normals and at risk (low scores on word & sentence production)
Normals At risk