Individual Differences in Morpheme and Syllable Access

A large body of behavioural and neural research have indicated that sub-lexical units above the phoneme level influence lexical access, in particular morphemes and syllables (e.g. Domínguez, Alija, Cuetos, & Vega, 2006; Dominguez, Vega, & Cuetos, 1997; Duñabeitia, Perea, & Carreira, 2008; Crepaldi, Hemsworth, Davis, & Rastle, 2015; Marslen-Wilson, Ford, Older, & Zhou, 1996). While morphemes are thought of as grammar- (syntax) and meaning-carrying units, syllables are a domain of the prosodic hierarchy and as such part of a language’s phonological system. Crucially, however, elements of the morphological and prosodic hierarchies do not always align (Booij and Rubach, 1984) and speech production studies indicate that syllabification is independent from word and morpheme-boundaries to a certain extent (though see Selkirk, 1982; Borowsky, 1986; Wells, 1990; Derwing, 1992). In language production, English speakers regularly syllabify the word ‚selecting‘ as ‚se.lec.ting‘, i.e. the /t/ is syllabified with the -ing suffix, but the affix itself does not carry a metrical code (Levelt, 1999). This raises the question as to how these potentially competing units may interact in lexical access, providing us with a novel angle to assess previous research and models of word processing, where this aspect was not taken into account. In particular, mixed results of inflectional priming effects have been explained with a difference in the processing of derivational and inflectional morphemes (Emmorey, 1989; Marjanovic & Crepaldi, preprint). This interpretation does not take into account that derivational morphemes are often full syllables in English and other languages, whereas inflections are often units below the syllable level. The present study addresses this difference by exploring the influence of syllable boundaries and ambisyllabicity on inflectional suffix priming in the visual modality. Work on syllable and prefix priming in Spanish indicates that syllables invoke competition due to activation of lexical entries sharing the same syllable (inhibitory hypothesis), whereas morphemes facilitate recognition (due to shared meaning; Domínguez, Alija, Cuetos, & Vega, 2006; Dominguez, Vega, & Cuetos, 1997). Whether syllables could evoke a similar sub-lexical search when they are not word-initial is unclear, but a likely possibility given the cross-linguistic evidence for syllabic units. As a result, we would expect facilitatory morphological effects only to surface for suffixes that do not conflict with syllable boundaries. In addition to this, previous results from exploratory analyses (Schwarz, Bozic, Post, 2020) indicate that a morphological priming effect may be stronger for individuals with slower reading speed and higher error rates, at least for inflected nonwords, indicating that individual differences in linguistic knowledge (such as vocabulary size and reading skill/profile) may be crucial for the emergence of morphological effects. Syllable effects, inhibitory effects of lexical search, in contrast, seem to be less affected by individual differences. It is unclear whether these individual differences also emerge for real words since most real words, by definition, are known to readers. Research Questions 1. Is morphemic access influenced by syllable processing in the visual modality? We investigate this question with a visual priming experiment, varying the syllable status of the -ing inflection in English target words (foa.ming vs. flow.ing). 2. Is morphemic activation modulated by individual differences in response speed and error rate? We investigate this question by planned median-split models, categorizing subjects into fast vs. slow responders and high vs. low error rate.