Martin Corley

Exposure-based models of human parsing: Evidence for the use of coarse-grained (nonlexical) statistical records

Several current models of human parsing maintain that initial structural decisions are influenced (or tuned) by the listeners or readers prior contact with language. The precise workings of these models depend upon the “grain,” or level of detail, at which previous exposures to language are analyzed and used to influence parsing decisions. Some models are premised upon the use of fine-grained records (such as lexical cooccurrence statistics). Others use coarser measures. The present paper considers the viability of models based exclusively on the use of fine-grained lexical records. The results of several studies are reviewed and the evidence suggests that, if they are to account for the data, experience-based parsers must draw upon records or representations that capture statistical regularities beyond the lexical level. This poses problems for several parsing models in the literature.

Syntactic priming in English sentence production: Categorical and latency evidence from an Internet-based study

To date, syntactic priming in sentence production has been investigated categorically, in terms of the probabilities of reusing particular syntactic structures. In this paper, we report a web-based replication of Pickering and Branigan (1998), Experiment 1, using a typed sentence completion paradigm that made it possible to record not only the responses made but also the response onset latency for each sentence completion. In conditions where priming occurred (as determined categorically), responses took less time when target completions were of the same type as preceding prime completions than when they differed. As well as validating Internet-based research by direct comparison with laboratory-based work, our findings strengthen the support for an architectural account of syntactic priming as envisaged by Pickering and Branigan.

It's the way that you, er, say it: hesitations in speech affect language comprehension.

Everyday speech is littered with disfluency, often correlated with the production of less predictable words (e.g., Beattie & Butterworth [Beattie, G., & Butterworth, B. (1979). Contextual probability and word frequency as determinants of pauses in spontaneous speech. Language and Speech, 22, 201-211.]). But what are the effects of disfluency on listeners? In an ERP experiment which compared fluent to disfluent utterances, we established an N400 effect for unpredictable compared to predictable words. This effect, reflecting the difference in ease of integrating words into their contexts, was reduced in cases where the target words were preceded by a hesitation marked by the word er. Moreover, a subsequent recognition memory test showed that words preceded by disfluency were more likely to be remembered. The study demonstrates that hesitation affects the way in which listeners process spoken language, and that these changes are associated with longer-term consequences for the representation of the message.

Timing accuracy of Web experiments: A case study using the WebExp software package

Although Internet-based experiments are gaining in popularity, most studies rely on directly evaluating participants’ responses rather than response times. In the present article, we present two experiments that demonstrate the feasibility of collecting response latency data over the World-Wide Web using WebExp—a software package designed to run psychological experiments over the Internet. Experiment 1 uses WebExp to collect measurements for known time intervals (generated using keyboard repetition). The resulting measurements are found to be accurate across platforms and load conditions. In Experiment 2, we use WebExp to replicate a lab-based self-paced reading study from the psycholinguistic literature. The data of the Web-based replication correlate significantly with those of the original study and show the same main effects and interactions. We conclude that WebExp can be used to obtain reliable response time data, at least for the self-paced reading paradigm.

Cascading influences on the production of speech: Evidence from articulation.

Recent investigations have supported the suggestion that phonological speech errors may reflect the simultaneous activation of more than one phonemic representation. This presents a challenge for speech error evidence which is based on the assumption of well-formedness, because we may continue to perceive well-formed errors, even when they are not produced. To address this issue, we present two tongue-twister experiments in which the articulation of onset consonants is quantified and compared to baseline measures from cases where there is no phonemic competition. We report three measure of articulatory variability: changes in tongue-to-palate contact using electropalatography (EPG, Experiment 1), changes in midsagittal spline of the tongue using ultrasound (Experiment 2), and acoustic changes manifested as voice-onset time (VOT). These three sources provide converging evidence that articulatory variability increases when competing onsets differ by one phonological feature, but the increase is attenuated when onsets differ by two features. This finding provides clear evidence, based solely on production, that the articulation of phonemes is influenced by cascading activation from the speech plan.

Exploring the Relationship Between Gestural Recognition and Imitation: Evidence of Dyspraxia in Autism Spectrum Disorders

In this study, the relationship between gesture recognition and imitation was explored. Nineteen individuals with Autism Spectrum Disorder (ASD) were compared to a control group of 23 typically developing children on their ability to imitate and recognize three gesture types (transitive, intransitive, and pantomimes). The ASD group performed more poorly than controls on all tasks of recognition and imitation. Higher performance on tests of working memory was associated with increased odds of successful imitation in both groups. Group differences remained even when working memory was statistically controlled for. An association was revealed in the ASD group between pantomime recognition and imitation but a similar association was not identified for intransitive gestures suggesting that recognition alone is not sufficient for imitation success.

Articulatory evidence for feedback and competition in speech production

We report an experimental investigation of slips of the tongue using a Word Order Competition (WOC) paradigm in which context (entirely non-lexical, mixed) and competitor (whether a possible phoneme substitution would result in a word or not) were crossed. Our primary analysis uses electropalatographic (EPG) records to measure articulatory variation, and reveals that the articulation of onset phonemes is affected by two factors. First, onsets with real word competitors are articulated more similarly to the competitor onset than when the competitor would result in a non-word. Second, onsets produced in a non-lexical context vary more from the intended onset than when the context contains real words. We propose an account for these findings that incorporates feedback between phonological and lexical representations in a cascading model of speech production, and argue that measuring articulatory variation can improve our understanding of the cognitive processes involved in speech production.

Finding Syntactic Structure in Unparsed Corpora The Gsearch Corpus Query System

The Gsearch system allows the selection of sentences by syntacticcriteria from text corpora, even when these corpora contain no priorsyntactic markup. This is achieved by means of a fast chart parser,which takes as input a grammar and a search expression specified by theuser. Gsearch features a modular architecture that can be extendedstraightforwardly to give access to new corpora. The Gsearcharchitecture also allows interfacing with external linguistic resources(such as taggers and lexical databases). Gsearch can be used withgraphical tools for visualizing the results of a query.

The role of inhibition in the production of disfluencies

Disfluency is a common occurrence in speech and is generally thought to be related to difficulty in the production system. One unexplored issue is the extent to which inhibition is required to prevent incorrect speech plans from being articulated. Therefore, we examined disfluency production in participants with attention-deficit/ hyperactivity disorder (ADHD), which is linked to deficits in inhibitory function and response suppression (Nigg, 2001). Participants completed a sentence production task in which they were presented with two pictures and a verb and their task was to produce a sentence. If inhibition plays a role in preventing incorrect speech plans, we would expect ADHD participants to produce more repetition and repair disfluencies than would non-ADHD controls. The results showed that one subtype of ADHD (i.e., the combined) produced more repair disfluencies as task demands increased. We conclude that the production system relies on inhibitory control in order to prevent errors in language production.

Listening to the sound of silence: disfluent silent pauses in speech have consequences for listeners

Silent pauses are a common form of disfluency in speech yet little attention has been paid to them in the psycholinguistic literature. The present paper investigates the consequences of such silences for listeners, using an Event-Related Potential (ERP) paradigm. Participants heard utterances ending in predictable or unpredictable words, some of which included a disfluent silence before the target. In common with previous findings using er disfluencies, the N400 difference between predictable and unpredictable words was attenuated for the utterances that included silent pauses, suggesting a reduction in the relative processing benefit for predictable words. An earlier relative negativity, topographically distinct from the N400 effect and identifiable as a Phonological Mismatch Negativity (PMN), was found for fluent utterances only. This suggests that only in the fluent condition did participants perceive the phonology of unpredictable words to mismatch with their expectations. By contrast, for disfluent utterances only, unpredictable words gave rise to a late left frontal positivity, an effect previously observed following ers and disfluent repetitions. We suggest that this effect reflects the engagement of working memory processes that occurs when fluent speech is resumed. Using a surprise recognition memory test, we also show that listeners were more likely to recognise words which had been encountered after silent pauses, demonstrating that silence affects not only the process of language comprehension but also its eventual outcome. We argue that, from a listeners perspective, one critical feature of disfluency is the temporal delay which it adds to the speech signal.