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Beyond Orthographic Segmentation: Neurophysiological Evidence That Pseudo-Derived Word Stems Are Processed Semantically

Morphological segmentation while reading is essential for new vocabulary learning. The study's aim was to investigate semantic-level morphological segmentation using event-related brain potentials (ERPs) in typical young adult readers. Past research has suggested that, because semantically opaque words prime their stems (e.g., corner/corn) similarly to transparent words (e.g., farmer/farm), readers recognize complex words from their constituent morphemes without regard to semantic information. However, this priming effect may be due to orthographic and phonological overlap between prime and target words. The research presented here addressed this possibility by creating five conditions in which orthographic, phonological, and semantic relationships between prime and target words were manipulated: Condition 1,wherein prime and target shared no relationship (e.g., inn/brother), served as Control. In Condition 2, prime and target were the same (e.g., brother/brother). In Condition 3, prime was the stem of target (e.g., broth/brother). Condition 4, our critical experimental condition, used primes semantically related to the stem of the target word (e.g., soup/brother). Finally, in Condition 5, prime was semantically related to the whole target word (e.g., sibling/brother). Semantically priming the stem (Condition 4) did not modulate the amplitude of the standard N400 ERP component (as did Conditions 2, 3, and 5), but did affect an early N400-like ERP component peaking in amplitude at ~262 ms after target. Other ERPs were observed that responded uniquely to shared orthography (Conditions 2, 3). Results set the stage for investigating morphological processing in adult reading impairments to evaluate whether, and to what extent, these readers semantically process morphological stems during text comprehension.

Identiferoai:union.ndltd.org:USF/oai:scholarcommons.usf.edu:etd-3007
Date13 March 2009
CreatorsHerbert, Theresa
PublisherScholar Commons
Source SetsUniversity of South Flordia
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceGraduate Theses and Dissertations
Rightsdefault

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