The richness of phonological and morphological representations in the lexicon

This strand of my program explores the the amount of information associated with the phonological and morphological representations that are stored in the lexicon.

Phonological representations

Within phonology, though there is widespread agreement that phonemic representations are composed of articulatory features, there are open questions about exactly how rich these representations should be. One class of theories, underspecification theories, has proposed that phonological representations only contain the features that cannot be predicted by the phonology of the language (a.o., Steriade, 1995; Lahiri & Reetz, 2002). Another class of theories, full-specification theories, has proposed that phonological representations contain all features, but crucially, certain features have a special status relative to others, such as markedness (a.o., Jakobson & Halle, 1956; Kiparsky, 1982; Prince & Smolensky, 1993/2004). One interesting development in this debate was the observation that an automatic electrophysiological response, the Mismatch Negativity (MMN) appears to be sensitive to differences between morphemes that has been attributed to featural underspecification or markedness (Eulitz & Lahiri, 2004, et seq.). Teasing apart underspecification and markedness approaches has been difficult within phonological theory, because they typically make similar empirical predictions. But MMN is much broader than phonological theory, as it is a low-level brain response generated by the auditory cortex (see Näätänen, 2001 for a review), and I have been exploiting the domain-generality of MMN elicitation to look for effects of markedness in auditory processing in domains that are adjacent to language such as the processing of biological sounds with potential social consequences. We found that the MMN response to a socially marked, non-linguistic sound such as [flatulence] was different from the MMN response to socially unmarked, non-linguistics sounds such as [cough] and [sniff] (Petrosino et al., submitted). These results seem to support the idea that the MMN response can be modulated by markedness alone, as there is no possibility of featural underspecification for these sounds. This may give support to the markedness approach for phonemes as well, since otherwise we need to assume a disjointed theory of the MMN modulation – i.e., that it arises for both markedness and underspecification. These results also demonstrate the values of research topics at the intersection of linguistics and other areas of cognitive science (like auditory processing and social cognition). As a final note, I ought to mention that this study was concluded prior to the pandemic, so it is possible that these values have changed in the current post-pandemic era. We are currently following up on this issue at NYUAD, by replicating the same experiment with a brand-new dry EEG system (i.e., without the need for conductive gel to active the electrodes) with a data quality comparable with that of traditional (gel-based) systems..

Morphological representations

Within the domain of morphology, theories of morphology have made no explicit arguments regarding the richness of morphological representations. A wealth of evidence from the masked priming literature on morphological decomposition (i.e., the real-time procedure of decomposing words into morphemes) have shown similar facilitation effects for (a) identical (city-CITY), (b) morphologically transparent (driver-DRIVE) and (c) morphologically opaque (brother-BROTH) pairs, but no effect for (d) orthographically related (brothel-BROTH) and (e) semantically related (cello-VIOLIN) pairs (Rastle et al., 2000; 2004). These results led to models of processing involving a level of morphological analysis, which is independent of the orthographic and semantic levels, and is accessed before meaning is available, as it only contains representations endowed with “morpho-orthographic” properties (such as orthographic transitional probability; Rastle & Davis, 2008). Building on these findings, my dissertation (Petrosino, 2020) asks whether morphological decomposition may be affected by other abstract linguistic properties such as whole-word lexicality, whole-word frequency, and syntactic categorization morphemes. The results suggest that at early stages of processing, morphological representations do contain, along with orthographic properties, at least some of the abstract linguistic properties that typify current theories of morphology—in particular, whole-word lexicality and frequency. Building on these results, I am currently investigating two main questions.

1. Are stem and affixes processed similarly?

In the literature, there is a sheer dichotomy between the masked priming response to English stems (boneless-BONE), which is usually found comparable in size with the repetition priming response (bone-BONE), and the masked priming response to English affixes (boneless-ILLNESS), which is usually null, or close to null in size. I am currently investigating, however, the possibility that the reported stem/affix asymmetry in the masked priming response may be an confound of the factual asymmetry between affixes (which by definition cannot be elicited as words on their own) and stems (which can be words on their own, but only in a limited subset of the world languages, like English). The experiment therefore aims to elicit the masked priming response to roots and affixes by using bimorphemic word pairs for both conditions (e.g., loveable-LOVELESS, jogger-FREEZER).

2. What are the mechanisms of (masked) priming?

The masked priming design has been used as the primary tool for investigations on sublimninal word processing. However, its mechanisms are still unclear. I am currently undertaking a reconsideration of the masked priming response in the light of the fundamental, often glossed-over problem of statistical power, which may lead to unreliable results. To tackle this issue, large sample sizes (N > 200 participants per experiment) may be collected only thanks to the capabilities of modern online programs. In Petrosino & Almeida (submitted) we show that, with the right sample size (quantified through a full-fledged power analysis), word frequency may interact with the masked priming response, in contrast with what has been believed for the last 40 years (Forster & Davis, 1984). These results pose an overarching question about the mechanics of masked priming, and, more broadly, challenges the actual suitability of the design for investigations on early stages of word recognition, as it suggests that prime masking may be actually unable to screen from episodic strategies. Further confirmation for an urgent reconsideration of the mechanisms underpinning morphological processing (and word recognition in general) can also be found in Petrosino, Sprouse & Almeida (in prep.), who report an extensive meta-analysis of five different replications (conducted both in-lab and online) of the traditional morphological masked priming experiment first reported by the seminal works by Rastle et al. (2000; 2004; see also above). The results show that, with a large sample size, the effects for (c) are rather statistically closer to (d), than to (a, b), which suggests that the purported dissociation of the morphological level from the orthographic level may not be as clear-cut as previously thought.