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First steps in Language Acquisition: Evidence from ERPs

This study explores the role of prosodic information in infants' language acquisition using the Event Related Potential (ERP) method. The results suggest that infants can identify word boundaries and syntactic phrase boundaries based on prosodic cues.

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First steps in Language Acquisition: Evidence from ERPs

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  1. First steps in Language Acquisition: Evidence from ERPs Angela D. Friederici Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany

  2. Method of Event Related Potential (ERP) • High temporal resolution as it measures the brain‘s activity millisecond by millisecond. • No behavioral reaction necessary.

  3. ERP method 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 200 400 600 800 1000 STIMULUS ONSET Time (ms)

  4. Infants' first Steps into Language are Based on Prosodic Information Theidentification 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. Theidentification of syntactic phrase boundariesis eased by prosodic information as each intonational phrase boundary is a syntactic phrase boundary.

  5. 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.

  6. dev sta sta sta sta sta Mismatch Negativity (MMN) ... is a pre-attentive response. ... is elicited by any discriminable change in repetitive auditory stimulation (oddball design): ... is the result of deviance detection.

  7. Experiment 1Discrimination of Syllables of Different Duration /ba:/ 341 ms /ba/ 202 ms Standard 5/6 Deviant 1/6 1. Block baa baa baa baa ba baa baa baa ba ... 2. Block ba ba ba ba baa ba ba ba baa ba ba ...

  8. 250406_130306_ba_long.fh11 The Mismatch Negativity MMN Adults: Difference wave between Deviant-Standard Source: Friedrich, Weber & Friederici, Psychophysiology, 2004

  9. CUNY_2006: 2411_ba_long.fh11 Experiment 1Discrimination of Syllables of Different Duration ERP and difference waves (Deviant-Standard) of 2-month-old infants Source: Friederici, Friedrich & Weber, NeuroReport, 2002

  10. 2203_CUNY_2006: 130306_ba_long.fh11 0705_Trieste_2006: 250406_130306_ba_long.fh11 Experiment 1Discrimination of Syllables of Different Duration Difference waves for long syllable in 2-month- old infants and adults Source: Friederici et al., NeuroReport, 2002; Friederici et al., 2004

  11. 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.

  12. 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.

  13. 0705_Trieste_2006: folie_16.fh11 Experiment 1b Difference waves for 2-month-olds with and without risk for SLI Source: Friedrich, Weber & Friederici, Psychophysiology, 2004

  14. 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.

  15. Block baaba baaba baaba babaa baaba baaba • Block babaa babaa babaa babaa baaba babaa Experiment 2Discrimination of Different Stress Patterns /ba:ba/ 750 ms /baba:/ 750 ms Standard 5/6 Deviant 1/6

  16. MMN Experiment 2Discrimination of Different Stress Patterns Difference waves 4- and 5-month-old infants Source: Weber, Hahne, Friedrich & Friederici, Cognitive Brain Research, 2004

  17. 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.

  18. 2203_CUNY_2006: alle_Folie21_weber.fh11 MMN Experiment 2bDiscrimination of Different Stress Patterns Difference waves 5-month-old infants Source: Weber, Hahne, Friedrich & Friederici, Cognitive Brain Research, 2004

  19. 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.

  20. 2203_CUNY_2006: alle_Folie23_weber.fh11 MMN Stress Pattern DiscriminationNovel Analysis: 5-month-olds At-risk group classification based on word production at 2 years. Source: Weber, Hahne, Friedrich & Friederici, Cognitive Brain Research, 2004

  21. 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?

  22. 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

  23. 2203_CUNY_2006: PhraseBoundary.fh11 Effect of Intonational Phrase Boundary Spoken sentences: Adults Source: Steinhauer, Alter & Friederici, Nature Neuroscience, 1999

  24. 2203_CUNY_2006: PhraseBoundary.fh11 Spoken Sentences: 8-month-old Infants Source: Pannekamp, Weber & Friederici, NeuroReport, in press

  25. 2203_CUNY_2006: PhraseBoundary.fh11 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

  26. basic mechanisms underlying the identification of intonational (syntactic) boundaries sensitivity to intonational phrase boundary CPS Development of Prosodic Perception basic mechanisms underlying the identification of word boundaries discrimination of syllable duration discrimination word stress pattern 2 5 8 Birth Months of age ERP- correlates MMN Source: Friederici, Trends in Cognitive Sciences, 2005

  27. 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.

  28. 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.

  29. 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.

  30. Lexical-Semantic Processing Paradigm “Ente” (duck) congruous “Ball” (ball) incongruous incongruous “Lampe” (lamp) “Schaf” (sheep) congruous time

  31. 2203_CUNY_2006: 130306_100106_fig4ausTiCS.fh11 Adults Adapted from Friederici,Trends in Cognitive Sciences, 2005

  32. 0705_Trieste_2006: 2607_IASCL-Berlin_2005: 19month_Exper4.fh11 N400 Experiment 4: Lexical-Semantic Processing ERP of 19-month-old infants Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2004

  33. 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

  34. 2203_CUNY_2006: 100106_fig4ausTiCS.fh11 19-month-olds Adults Adapted from Friederici,Trends in Cognitive Sciences, 2005

  35. 2203_CUNY_2006: 100106_fig4ausTiCS.fh11 14-month-olds 19-month-olds Adults Adapted from Friederici,Trends in Cognitive Sciences, 2005

  36. 2203_CUNY_2006: 100106_fig4ausTiCS.fh11 12-month-olds 14-month-olds 19-month-olds Adults Adapted from Friederici,Trends in Cognitive Sciences, 2005

  37. 2511_fig4ausTiCS.fh11 bildwort3d.ppt (Maren) 12-month-olds 14-month-olds 19-month-olds 400 – 700 ms 400 – 700 ms 400 – 700 ms

  38. Con_inc_12_mo_no_fam_risk early neg. early neg. Experiment 4: Lexical-Semantic Processing ERP of 12-month-old infants Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2005

  39. 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.

  40. 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.

  41. Lexical processing Lexical form Lexical semantics 12 14 N400 Development of Auditory Language PerceptionBasic stages and ERP correlates Identification of intonational boundaries Identification of word boundaries Developmental stages Discrimination word stress pattern Sensitivity to intonational phrase boundary Discrimination of phonemes 2 3 6 7 8 4 5 Birth Months of age ERP correlates months of age MMN CPS Adapted from Friederici, Trends in Cognitive Sciences, 2005

  42. Lexical processing Sentence processing Local phrase structure building Selectional restriction of verbs Lexical form Lexical semantics 12 14 19 32 N400 ELAN-P600 Development of Auditory Language PerceptionBasic stages and ERP correlates Identification of intonational boundaries Identification of word boundaries Developmental stages Discrimination word stress pattern Sensitivity to intonational phrase boundary Discrimination of phonemes 2 3 6 7 8 4 5 Birth Months of age ERP correlates months of age MMN CPS Adapted from Friederici, Trends in Cognitive Sciences, 2005

  43. MAX FOR HUMAN PLANCK COGNITIVE AND BRAIN SCIENCES INSTITUTE LEIPZIG Manuela Friedrich Anja Hahne Birgit Herold Claudia Männel Regine Oberecker Ann Pannekamp Christiane Weber

  44. 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.

  45. semantic violation CZ Semantic Violation N400 Cz -5 µV correct: "Das Baby wurde gefüttert" "The baby was fed" incorrect: "Das Lineal wurde gefüttert" 5 "The ruler was fed" 0 0.5 1 sec correct incorrect Source: Hahne & Friederici, Cognitive Brain Research, 2002

  46. 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

  47. N400 Experiment 5: ERP of 24-month-olds Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2004

  48. 2607 Berlin IACL 2005 N400 Experiment 5: ERP of 19-month-olds Source: Friedrich & Friederici, Journal of Cognitive Neuroscience, 2004

  49. 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.

  50. 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).

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