1. Bornkessel, Fiebach, Friederici, & Schlesewsky (2004) What individual difference measures best predict differences in language comprehension? –Working Memory Capacity? Daneman & Carpenter’s Reading Span test Very mixed results –Ability to inhibit irrelevant information? (Probably plays some role in Reading Span performance) Individual Alpha Frequency (IAF) Alpha consists of lower and upper freq bands Desynchronization in –Upper freq band related to semantic memory processing –Lower freq band related to attention

2. German Sentences German has gender, number, & case morphology –But some gender/number/case combos are ambiguous It also has more flexible word order than English –SVO = default –But both SO and OS are possible orders –And verbs are clause-final in embedded clauses –SO easier to process than OS –When case is ambiguous, prefer to interpret as SO

3. Expt 1 Stimuli Udo weiß daß… Ambiguous …|die Gärtnerin am Sontag nachmittag hinter der Kirche |den Jäger… …|die Gärtnerin am Sontag nachmittag hinter der Kirche |der Jäger … Unambiguous …|der Gärtner am Sontag nachmittag hinter der Kirche |den Jäger … …|den Gärtner am Sontag nachmittag hinter der Kirche |der Jäger … … gesehen hat. - die G ä rtnerin could be either a subject or an object - Its role is only disambiguated at der/den Jäger - der G ä rtner can only be a subject - den G ä rtner can only be an object

4. Previous Individual Difference Results for German Sentences Friederici et al. (1998) –P600 reanalysis effect at word disambiguating toward OS order in ambiguous sentences But only for High Verbal Span participants Maybe Low Spans couldn’t inhibit OS interpretation & so didn’t need to reanalyze? Bornkessel et al. (2004) –Again P600 reanalysis effect at word disambig toward OS order in ambig sentences Again only for High Spans –Also during ambiguous region, sustained parietal positivity But only for Low Spans Maybe because carrying two possible interpretations along?

5. Individual Differences Measures Used in Expt 1 Reading Span –10 High Span (mean 4.8) –10 Low Span (mean 2.5) Individual Alpha Frequency (during rest) –10 High IAF (mean 10.7 Hz) –10 Low IAF (mean 9.4 Hz) Response Speed for Comprehension Qs –Median split (median = 2.3 sec) Response Accuracy –Median split (median = 15.9% errors)

6. Procedure Sentences presented phrase-by-phrase –(unusual for ERP data collection!) –Single words: SOA = 500 msec = Duration 400 msec + 100 msec ISI –Two-word phrases: 600 msec SOA = Duration 500 msec + 100msec ISI Task = True/False judgment for paraphrase

7. ERPs During Ambiguous Region by High and Low Reading Span - Positivity doesn’t last throughout ambiguous region - Its size during 750-1250 msec window equal for 2 span groups die Gärtnerin am Sontag nachmittag hinter der Kirche

8. ERPs During Ambiguous Region by Fast and Slow Responders - Positivity doesn’t last throughout ambiguous region - Its size during 750-1250 msec window equal for 2 response speed groups

9. ERPs During Ambiguous Region by Accurate and Inaccurate Responders - Positivity doesn’t last throughout ambiguous region - Its size during 750-1250 msec window equal for 2 accuracy groups

10. ERPs During Ambiguous Region by High and Low IAF - Positivity does last throughout ambiguous region, but it’s only significant for Low IAF group

11. Expt 1 Conclusion High IAF participants were able to inhibit the possible OS interpretation –They showed P600 effect at disambiguation in Ambig OS condition (Only described, no figure shown in paper!) Low IAF participants were carrying along two interpretations –Reflected in the parietal positivity during the ambiguous region –And no P600 at disambiguation

12. Experiment 2 Will quantifier scope ambiguity produce similar results? Maria weiß daß… Ambiguous … einem Vater jeder Lehrer dankte. (It could mean that all of the teachers thanked the same father, or that they each thanked a different father.) Unambiguous … dem Vater der Lehrer dankte.

13. ERPs During Ambiguous Region Positivity significant only for Low IAF group

14. Conclusions There’s a “sustained” parietal positivity during ambiguous sentence regions But only for Low IAF participants –Because carrying two interpretations along? –Because they can’t effectively inhibit the dispreferred option? So, differences in inhibitory control explain individual differences better than working memory capacity, response speed, & response accuracy