Access to word meanings during spoken language comprehension: Effects of sentential semantic context.

In 3 cross-modal priming experiments, the authors investigated whether access to a word's meaning is affected by the semantic context in which it is heard or is exhaustive and context-independent. The access of nonassociated semantic properties and normatively associated words before and after prime offset was probed. Whereas associated targets were primed context-independently, access to semantic property targets was affected by the sentential context. Semantic property targets showed greater priming in a sentence biasing to a specific semantic property than in a neutral condition, even when this bias made the target property irrelevant rather than relevant. These results cannot be accounted for by current exhaustive access or context-dependency theories of lexical access. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accessing spoken words: The importance of word onsets.

Approaches to spoken word recognition differ in the importance they assign to word onsets during lexical access. This research contrasted the hypothesis that lexical access is strongly directional with the hypothesis that word onsets are less important than the overall goodness of fit between input and lexical form. A cross-modal priming technique was used to investigate the extent to which a rhyme prime (a prime that differs only in its first segment from the word that is semantically associated with the visual probe) is as effective a prime as the original word itself. Earlier research had shown that partial primes that matched from word onset were very effective cross-modal primes. The present results show that, irrespective of whether the rhyme prime was a real word or not, and irrespective of the amount of overlap between the rhyme prime and the original word, the rhymes are much less effective primes than the full word. In fact, no overall priming effect could be detected at all except under conditions in which the competitor environment was very sparse. This suggests that word onsets do have a special status in the lexical access of spoken words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Levels of perceptual representation and process in lexical access: Words, phonemes, and features.

Three experiments and a simulation study investigate competing featural and phonemic views of the representation of the speech input in access to the mental lexicon. Auditory lexical decision and gating tasks show that the processing consequences of subcategorical mismatches (conflicts between phonetic cues to speech segment identity) depend on the lexical status of the conflicting cues, such that conflicts that only involve nonwords do not disrupt performance. A further study, using a phonetic-decision task with the same stimuli, found the same pattern. A simulation study shows that the interactive activation model TRACE, with top-down feedback to a prelexical phonemic level, does not model these effects successfully. The authors argue instead for a direct access featural model, based on a distributed computational substrate, where featural information is mapped directly onto lexical representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanisms of phonological inference in speech perception.

Cross-modal priming experiments have shown that surface variations in speech are perceptually tolerated as long as they occur in phonologically viable contexts. For example, [fre[i]p] (frayp) gains access to the mental representation of freight when in the context of [fre[i]pbeara] (frayp bearer) because the change occurs in normal speech as a process of place assimilation. The locus of these effects in the perceptual system was examined. Sentences containing surface changes were created that either agreed with or violated assimilation rules. The lexical status of the assimilated word also was manipulated, contrasting lexical and nonlexical accounts. Two phoneme monitoring experiments showed strong effects of phonological viability for words, with weaker effects for nonwords. It is argued that the listener's percept of the form of speech is a product of a phonological inference process that recovers the underlying form of speech. This process can operate on both words and nonwords, although it interacts with the retrieval of lexical information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Leading up the lexical garden path: Segmentation and ambiguity in spoken word recognition.

Two gating studies, a forced-choice identification study and 2 series of cross-modal repetition priming experiments, traced the time course of recognition of words with onset embeddings (captain) and short words in contexts that match (cap tucked) or mismatch (cap looking) with longer words. Results suggest that acoustic differences in embedded syllables assist the perceptual system in discriminating short words from the start of longer words. The ambiguity created by embedded words is therefore not as severe as predicted by models of spoken word recognition based on phonemic representations. These additional acoustic cues combine with post-offset information in identifying onset-embedded words in connected speech. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Morphology and meaning in the English mental lexicon.

Investigated the lexical entry for morphologically complex words in English. Six experiments, using a cross-modal repetition priming task, asked whether the lexical entry for derivationally suffixed and prefixed words is morphologically structured and how this relates to the semantic and phonological transparency of the surface relationship between stem and affix. There was clear evidence for morphological decomposition of semantically transparent forms. This was independent of phonological transparency, suggesting that morphemic representations are phonologically abstract. Semantically opaque forms, in contrast, behave like monomorphemic words. Overall, suffixed and prefixed derived words and their stems prime each other through shared morphemes in the lexical entry, except for pairs of suffixed forms, which show a cohort-based interference effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual distance and competition in lexical access

Two experiments use rhyme priming techniques to explore the decision space for lexical access. The 1st experiment, using intramodal (auditory-auditory) priming, covaried the phonological distance of a spoken rhyme prime (e.g., pomato) from its source word (e.g., tomato) with the presence or absence of close lexical competitors. The results showed strong effects of phonological distance and no significant effects of competitor environment. The 2nd experiment, using ambiguous rhyme primes in a cross-modal (auditory-visual) priming task, showed that phonetically ambiguous primes could fully match their source words, but only in the appropriate lexical environment. The results support a view of lexical access in which the listener's perceptual experience is based on strict requirements for a bottom-up match with the speech input, and in which competitor environment does not directly modulate the on-line goodness-of-fit computation.     

Phonological variation and inference in lexical access.

Recent experiments have indicated that lexical access in speech is highly intolerant of mismatch. An isolated sequence such as [wlk1b] strongly disrupts access to the underlying lexical entry (wicked). This observation seems inconsistent with the systematic variability found in the phonetic form of words. Two cross-modal priming experiments tested the hypothesis that phonologically regular variation is perceptually acceptable. Participants heard tokens like [wlk1b] embedded in contexts that either licensed the change as a result of a regular assimilation process (e.g., [wlk1b pr?nk]) or rendered the change phonologically unviable (e.g., [wlk1b gelm]). The tokens with contextually unviable deviations did not effectively access lexical representations. In contrast, the same tokens in viable phonological context primed as strongly as unchanged controls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The nature of sublexical processing in reading Chinese characters.

The nature of sublexical processing in reading complex (or compound) Chinese characters was investigated in 3 printed naming experiments using native speakers of Mandarin Chinese. In Experiments 1 and 2, facilitatory priming effects were observed for target characters, which were semantically related to the phonetic radicals embedded in complex characters but not to the complex characters themselves. In Experiment 3, the presence of semantic primes, which were related to the phonetic radicals embedded in the complex targets but not to the targets themselves, was found to increase the naming latencies to the targets. It is argued that sublexical processing in reading Chinese is both a phonological and a semantic event. There are no fundamental differences between sublexical processing of phonetic radicals and lexical processing of simple and complex characters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)