First steps in Language Acquisition:
Evidence from ERPs
Angela D. Friederici
Max Planck Institute for Human Cognitive and Brain Sciences
Leipzig, Germany
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Method of Event Related Potential (ERP)
• High temporal resolution
as it measures the brain‘s
activity millisecond by
millisecond.
• No behavioral reaction
necessary.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
ERP method
ONGOING EEG
Amplifier
S
S
S
S
one sec
AUDITORY EVENT-RELATED POTENTIAL
-6 µV
N400
Signal
averager
ELAN
AUDITORY
STIMULUS
(S)
P600
P200
+6 µV
STIMULUS
ONSET
Trieste, 07.05.2006
200
400
600
800
1000
Time (ms)
Max Planck Institute for Human Cognitive and Brain Sciences
Infants' first Steps into Language are Based on
Prosodic Information
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.
The identification of syntactic phrase boundaries is eased by
prosodic information as each intonational phrase boundary
is a syntactic phrase boundary.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Mismatch Negativity (MMN)
... is a pre-attentive response.
... is elicited by any discriminable
change in repetitive auditory
stimulation (oddball design):
sta
sta
sta
dev
sta
sta
... is the result of deviance detection.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 1
Discrimination of Syllables of Different Duration
/ba:/ 341 ms
/ba/ 202 ms
Standard
5/
6
Deviant
1/
6
1. Block
baa
2. Block
ba
Trieste, 07.05.2006
baa
ba
ba
baa
baa
ba
baa
ba
baa
ba
ba
baa
ba
baa
baa
ba
ba
...
ba
...
Max Planck Institute for Human Cognitive and Brain Sciences
The Mismatch Negativity MMN
Adults: Difference wave between DeviantStandard
Source: Friedrich, Weber & Friederici, Psychophysiology, 2004
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 1
Discrimination of Syllables of Different Duration
ERP and difference waves (Deviant-Standard)
of 2-month-old infants
Source: Friederici, Friedrich & Weber, NeuroReport, 2002
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 1
Discrimination of Syllables of Different Duration
Difference waves for long syllable in 2-monthold infants and adults
Source: Friederici et al., NeuroReport, 2002; Friederici et al., 2004
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Hypothesis for SLI
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 1b
Difference waves for 2-month-olds with and without
risk for SLI
Source: Friedrich, Weber & Friederici, Psychophysiology, 2004
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 2
Discrimination 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
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 2
Discrimination of Different Stress Patterns
Difference waves
4- and 5-month-old infants
MMN
Source: Weber, Hahne, Friedrich & Friederici, Cognitive Brain Research, 2004
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 2b
Discrimination of Different Stress Patterns
Difference waves
5-month-old infants
MMN
Source: Weber, Hahne, Friedrich & Friederici, Cognitive Brain Research, 2004
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Stress Pattern Discrimination
Novel Analysis: 5-month-olds
At-risk group classification based on word production at
2 years.
MMN
Source: Weber, Hahne, Friedrich & Friederici, Cognitive Brain Research, 2004
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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?
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 3
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 ...
Source: Steinhauer, Alter & Friederici, Nature Neuroscience, 1999
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Effect of Intonational Phrase Boundary
Spoken sentences: Adults
Source: Steinhauer, Alter & Friederici, Nature Neuroscience, 1999
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Spoken Sentences: 8-month-old Infants
Source: Pannekamp, Weber & Friederici, NeuroReport, in press
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Summary Experiment 3
Infants by the age of 8 months show a brain response
to intonational phrase boundary similar to that of
adults.
adults
Trieste, 07.05.2006
8-month-old infants
Max Planck Institute for Human Cognitive and Brain Sciences
Development of Prosodic Perception
basic mechanisms underlying the
identification of intonational
(syntactic) boundaries
basic mechanisms underlying the
identification of word boundaries
ERPcorrelates
discrimination
of syllable
duration
Birth
2
discrimination
word stress
pattern
sensitivity to
intonational phrase
boundary
5
MMN
8
Months of age
CPS
Source: Friederici, Trends in Cognitive Sciences, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Processing Lexical-Semantic Information
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 4: Lexical-Semantic Processing
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 4: Lexical-Semantic Processing
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Lexical-Semantic Processing Paradigm
“Ente” (duck)
congruous
“Ball” (ball)
incongruous
“Lampe” (lamp)
time
Trieste, 07.05.2006
incongruous
“Schaf” (sheep)
congruous
Max Planck Institute for Human Cognitive and Brain Sciences
Adults
Adapted from Friederici,Trends in Cognitive Sciences, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 4: Lexical-Semantic Processing
ERP of 19-month-old infants
N400
Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2004
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 4: Lexical-Semantic Processing
ERP of 19-month-old infants: normals and at risk
(low scores on word & sentence production)
Normals
At risk
Source: Friedrich & Friederici, Psychophysiology, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
19-month-olds
Adults
Adapted from Friederici,Trends in Cognitive Sciences, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
14-month-olds
19-month-olds
Adults
Adapted from Friederici,Trends in Cognitive Sciences, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
12-month-olds
14-month-olds
19-month-olds
Adults
Adapted from Friederici,Trends in Cognitive Sciences, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
12-month-olds
14-month-olds
19-month-olds
400 – 700 ms
400 – 700 ms
400 – 700 ms
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 4: Lexical-Semantic Processing
ERP of 12-month-old infants
early neg.
early neg.
Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Summary Experiment 4
Lexical-Semantic Processing
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).
• 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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Conclusion Experiment 4
The occurrence of a phonological-lexical priming effect in
both age groups implies that not only 14-, but also 12month-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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
ERP correlates
Developmental stages
Development of Auditory Language Perception
Basic stages and ERP correlates
Identification of
intonational
boundaries
Identification of word
boundaries
Discrimination
of phonemes
Birth 2
3
Discrimination
word stress
pattern
4
5
6
Sensitivity to
intonational
phrase boundary
7
8
Lexical
processing
Lexical
form
Lexical
semantics
12
14
Months of age
MMN
CPS
N400
months of age
Adapted from Friederici, Trends in Cognitive Sciences, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
ERP correlates
Developmental stages
Development of Auditory Language Perception
Basic stages and ERP correlates
Identification of
intonational
boundaries
Identification of word
boundaries
Discrimination
of phonemes
Birth 2
3
Discrimination
word stress
pattern
4
5
6
Sensitivity to
intonational
phrase boundary
7
8
Lexical
processing
Sentence processing
Lexical
form
Lexical
semantics
Selectional
restriction
of verbs
Local
phrase
structure
building
12
14
19
32
Months of age
MMN
CPS
N400
months of age
ELAN-P600
Adapted from Friederici, Trends in Cognitive Sciences, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
MAX
PLANCK
INSTITUTE
FOR
HUMAN
COGNITIVE AND BRAIN SCIENCES
LEIPZIG
Manuela Friedrich
Anja Hahne
Birgit Herold
Claudia Männel
Regine Oberecker
Ann Pannekamp
Christiane Weber
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Semantic Violation
N400
Cz
correct:
-5
µV
"Das Baby wurde gefüttert"
"The baby was fed"
incorrect:
"Das Lineal wurde gefüttert"
"The ruler was fed"
5
0
0.5
correct
incorrect
1
sec
CZ
Source: Hahne & Friederici, Cognitive Brain Research, 2002
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 5: ERP of 24-month-olds
N400
Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2004
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 5: ERP of 19-month-olds
N400
Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2004
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Processing Syntactic Information
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).
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Syntactic Violation
F7
-5 µV
correct:
ELAN
"Das Hemd wurde gebügelt."
"The shirt was ironed."
5
incorrect:
0.5
1
sec
0.5
1
sec
Pz
"Die Bluse wurde am gebügelt."
-5 µV
"The blouse was on ironed."
correct
incorrect
0
F7
5
PZ
0
P600
Source: Hahne & Friederici, Cognitive Brain Research, 2002
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 6: Syntactic Processing
Experiment 6 investigates at what age we can detect
syntax-related ERP components. In this experiment
syntactic violations were realized in simple active
sentences.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
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
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 6: Syntax adults
ELAN
P600
Source: Oberecker, Friedrich & Friederici, Journal of Cognitive Neuroscience, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 6: Syntax 32-month-old children
ELAN
P600
Source: Oberecker, Friedrich & Friederici, Journal of Cognitive Neuroscience, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 6: Syntax 24-month-old children
P600
Source: Oberecker & Friederici, submitted
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
24-month-old
children
-10
32-month-old
children
µV
-10
µV
ELAN
0.8
1.6
P600
correct
incorrect
Trieste, 07.05.2006
µV
ELAN
s
0.8
1.6
1.6
5
10
10
-5
s
s
0.8
Adults
P600
correct
incorrect
P600
correct
incorrect
Max Planck Institute for Human Cognitive and Brain Sciences
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).
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Experiment 7: Syntax 32-month-olds at risk
Source: Oberecker & Friederici, in preparation
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
No risk
24-month-olds
-10
No risk
32-month-olds
µV
-10
µV
ELAN
0.8
1.6
P600
correct
incorrect
Trieste, 07.05.2006
µV
s
0.8
1.6
1.6
15
10
10
-15
s
s
0.8
Risk
32-month-olds
P600
correct
incorrect
correct
incorrect
Max Planck Institute for Human Cognitive and Brain Sciences
Conclusion Experiment 7
Children with risk for SLI do not demonstrate an ELANP600 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.
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences
Processing Phonotactically legal and illegal Pseudowords
ERP of 19-month-old infants: normals and at risk
(low scores on word & sentence production)
Normals
At risk
Source: Friedrich & Friederici, Psychophysiology, 2005
Trieste, 07.05.2006
Max Planck Institute for Human Cognitive and Brain Sciences