Introduction

1. Morpho-Orthographic and Morpho-Semantic Influences in Early Visual Word Recognition: An ERP Investigation Using Masked PrimingJoanna Morris1, Jonathan Grainger2 & Phillip J. Holcomb3Hampshire College, Amherst, MA1; CNRS & University of Provence, Marseille, France2;Tufts University, Medford, MA3 • Discussion • In both experiments, we found a significant reduction in the N250 for related items across all three conditions. • In Experiment 2 we also found a reduction of the N400 component. • For both the N250 and the N400, the effects for the Opaque and Orthographic conditions were not as robust as for the Transparent condition. • These data suggest that masked morphological priming is at least partly subtended by an early pre-lexical decomposition mechanism that works best for transparent primes. • Because both the N250 and the N400 showed graded effects across with three conditions, our data suggest that the pre-lexical decomposition mechanism is based on properties that change in a monotonic fashion among the three conditions. One such property is the strength of the transition probabilities between bigrams (See Figure 4). • The results of the present study suggest that the N250 component is sensitive to statistical sublexical regularities, such as transitional probabilities that govern a chunking process that divides the stimulus into salient sub-units. The fact that these sub-units often correspond to morphemes would simply be because morphemes, by definition, represent highly recurring orthographic and phonological patterns. • Introduction • Complex words may be either (a) stored as full forms in the mental lexicon, or (b) undergo decomposition into their constituent morphemes during processing • The latter account of morphological processing is supported by the finding that the presentation of a morphologically related prime facilitates target processing, and the effects of morphological priming are greater than those found for purely semantically related or purely orthographically related primes. • Morphological priming effects can be accommodated by two classes of models. The supra-lexical model (Giraudo and Grainger 2000; 2001), holds that morphologically complex words are represented as whole units at the level of form, but that morphological relatives are linked to common morphological representations at a higher, more abstract level of linguistic structure. • In contrast to the supra-lexical account, Taft and Forster (Taft, 1994; Taft & Forster, 1975) have proposed a sub-lexical model in which morphemes are activated via their constituent graphemes, and these activated morphemes in turn activate the word units above them • The supra-lexical and sub-lexical hypotheses differ with respect to their predications about the role of semantic relatedness in morphological priming. Figure 2: ERPs to targets preceded by primes with a (a) semantically transparent (b) semantically opaque and (c) orthographic relationship. Prime duration is 50 ms

2. In the supra-lexical model, morphological representations are contacted after whole-word representations, and thus the meaning of the whole-word should influence the extraction of the morphological constituents that comprise the word. Thus only semantically transparent morphological primes should result in facilitation of target processing. • Recent studies that have obtained significant priming with semantically opaque primes have been problematic for the supra-lexical hypothesis (Longtin, Segui, & Halle, 2003; Rastle, Davis, & New, 2004) • The goal of the current set of studies was to investigate the role of semantic information in the segmentation of morphologically complex words, by examining event-related responses to targets primed by semantically transparent, semantically opaque and orthographically, but not morphologically, related primes using the masked priming paradigm. • Method • 48 adults (9 men and 15 women in Experiment 1 and 13 men and 11 women in Experiment 2). Age Range: 18-26 yrs (Mean = 20.8 yrs.) • The stimuli were 324 prime-target pairs that had (a) were morphologically related and had a semantically and orthographically transparent relationship (hunter-hunt), (b) were not morphologically related and had a semantically opaque relationship (corner-corn) (c) were orthographically but not semantically or morphologically related (scandal-scan). • The primes were presented for 50 milliseconds in Experiment 1 and for 100 milliseconds in Experiment 2 in order to manipulate the degree of prime processing. • Subjects were instructed to monitor the list of words for words that referred to articles of clothing and press a button on a game controller when such a word appeared. Figure 3: ERPs to targets preceded by primes with a (a) semantically transparent (b) semantically opaque and (c) orthographic relationship. Prime duration is 100 ms References Giraudo, H., & Grainger, J. (2000). Effects of prime word frequency and cumulative root frequency in masked morphological priming. Language & Cognitive Processes, 15(4-5), 421-444. Giraudo, H., & Grainger, J. (2001). Priming complex words: Evidence for supralexical representation of morphology. Psychonomic Bulletin & Review, 8(1), 127-131. Longtin, C.-M., Segui, J., & Halle, P. A. (2003). Morphological priming without morphological relationship. Language & Cognitive Processes, 18(3), 313-334. Rastle, K., Davis, M. H., & New, B. (2004). The broth in my brother's brothel: Morpho-orthographic segmentation in visual word recognition. Psychonomic Bulletin & Review, 11(6), 1090-1098. Taft, M. (1994). Interactive-activation as a framework for understanding morphological processing. Language & Cognitive Processes, 9(3), 271-294. Taft, M., & Forster, K. I. (1975). Lexical storage and retrieval of prefixed words. Journal of Verbal Learning & Verbal Behavior, 14(6), 638-647. Figure 4 Figure 1 This research was supported by HD25889 and HD043251