Kim & Osterhout (2005) JML The independence of combinatory semantic processing: Evidence from event-related potentials

Background Everyone believes –N400 reflects semantic processing difficulty –P600 reflects form-related processing difficulty However, 2 studies have found P600 when they expected to find N400 –Kolk et al. (2003) found P600 at joeg De vos die op de stropers joeg … The fox that the poachers hunted … = The fox that hunted the poachers … –Kuperberg et al. (2003) also found P600 at eat For breakfast, the eggs would only eat … In both cases, there was a noun that was plausible in some role of the verb’s event, just not the role its position indicated it had

Experiment 1 - Stimuli Active Control –The hungry boy was DEVOURING the cookies. Passive Control –The hearty meal was DEVOURED by the kids. Anomaly –The hearty meal was DEVOURING the kids.

Procedures/Design Sentences presented word-by-word centrally SOA = 650 msec (slow!) End-of-sentence acceptability judgments Expt 1 –N = 24 –96 sets of 3 sentence versions (32) –107 distractors, some sem anom, some ungramm Numbers varied across lists to make acceptability ~50/50 – – 203 trials (58% acceptable, 42% unacceptable) Expt 2 –N = 29 –96 sets of 3 sentence versions (32) –112 distractors, some sem anom, some ungramm Numbers varied across list to make acceptability ~50/50 – = 208 (50% acceptable, 50% unacceptable

Experiment 1 - Results P600

Experiment 1 - Discussion Why does “The hearty meal was devouring…” evoke P600 rather than N400? –Because hearty meal can play SOME thematic role in a devouring event? –Maybe the fact that hearty meal fits so well with devouring makes the processing system think there’s a grammatical error, like the wrong inflection on devouring, rather than a semantic anomaly

Experiment 2 - Stimuli Passive Control –The hearty meal was DEVOURED … No-attraction Violation –The dusty tabletops were DEVOURING … Attraction Violation –The hearty meal was DEVOURING …

Experiment 2 - Results N400

Experiment 2 - Discussion Argue that these results show that –Semantic processing can “drive” sentence comprehension –Rather than always having to wait for structural processing to give the relationships among words before their semantic combination can proceed