Form-based priming in spoken word recognition: the roles of competition and bias

Representational level matters for tone-word recognition: Evidence from form priming

In a form priming experiment with a lexical decision task, we investigated whether the representational structure of lexical tone in lexical memory impacts spoken-word recognition in Mandarin. Target monosyllabic words were preceded by five types of primes: (1) the same real words (/lun4/-/lun4/), (2) real words with only tone contrasts (/lun2/-/lun4/), (3) unrelated real words (/pie3/-/lun4/), (4) pseudowords with only tone contrasts (*/lun3/-/lun4/), and (5) unrelated pseudowords (*/tai3/-/lun4/). We found a facilitation effect in target words with pseudoword primes that share the segmental syllable but contrast in tones (*/lun3/-/lun4/). Moreover, no evident form priming effect was observed in target words primed by real words with only tone contrasts (/lun2/-/lun4/). These results suggest that the recognition of a tone word is influenced by the representational level of tone accessed by the prime word. The distinctive priming patterns between real-word and pseudoword primes are best explained by the connectionist models of tone-word recognition, which assume a hierarchical representation of lexical tone.

Using network science to examine audio-visual speech perception with a multi-layer graph

To examine visual speech perception (i.e., lip-reading), we created a multi-layer network (the AV-net) that contained: (1) an auditory layer with nodes representing phonological word-forms and edges connecting words that were phonologically related, and (2) a visual layer with nodes representing the viseme representations of words and edges connecting viseme representations that differed by a single viseme (and additional edges to connect related nodes in the two layers). The results of several computer simulations (in which activation diffused across the network to simulate word identification) are reported and compared to the performance of human participants who identified the same words in a condition in which audio and visual information were both presented (Simulation 1), in an audio-only presentation condition (Simulation 2), and a visual-only presentation condition (Simulation 3). Another simulation (Simulation 4) examined the influence of phonological information on visual speech perception by comparing performance in the multi-layer AV-net to a single-layer network that contained only a visual layer with nodes representing the viseme representations of words and edges connecting viseme representations that differed by a single viseme. We also report the results of several analyses of the errors made by human participants in the visual-only presentation condition. The results of our analyses have implications for future research and training of lip-reading, and for the development of automatic lip-reading devices and software for individuals with certain developmental or acquired disorders or for listeners with normal hearing in noisy conditions.

Investigation of Mandarin Word Production in Children and Adults: Evidence from Phonological Priming with Non-words

Using a cross-modal picture-word interference (PWI) task, we examined phonological representations and encoding in Mandarin-speaking children and adults. Pictures of monosyllabic words were presented visually, with auditory primes presented before, concurrent with, or after the picture's appearance (SOA -200, -100, 0, +150). Primes were related to the targets in terms of Onset, Rhyme, Tone, Onset and Tone, Rhyme and Tone, or were unrelated. The rhymes of target words were counterbalanced between simple and complex structures to examine effects of rhyme complexity. Twenty Mandarin-speaking adults (aged 20;3 to 23;10), 20 school-age children (aged 9;1 to 10;11) and 20 preschoolers (aged 5;0 to 5;11) were asked to name the pictures as quickly as possible while ignoring the primes played over a headset. The results showed that adults exhibited consistent Onset and Onset-Tone priming effects across later SOAs, while the older children (9- to 10-year-olds) exhibited Onset, Rhyme, Onset-Tone and Rhyme-Tone priming effects across later SOAs. The younger children (5-year-olds), in contrast, exhibited Rhyme and Rhyme-Tone priming effects at the earliest SOA. For both groups of children, Rhyme and Rhyme-Tone priming effects were complexity-dependent. Our findings suggest that the phonological representations of Mandarin speakers develop from holistic units into those with an onset-based structure. Moreover, an incremental processing pattern at the sub-syllabic level is gradually developed around the age of 9 or 10, though susceptibility to holistic phonological similarity is retained to some degree.

Intraspeaker Priming across the New Zealand English Short Front Vowel Shift

A growing body of research in psycholinguistics, corpus linguistics, and sociolinguistics shows that we have a strong tendency to repeat linguistic material that we have recently produced, seen, or heard. The present paper investigates whether priming effects manifest in continuous phonetic variation the way it has been reported in phonological, morphological, and syntactic variation. We analyzed nearly 60,000 tokens of vowels involved in the New Zealand English short front vowel shift (SFVS), a change in progress in which trap/dress move in the opposite direction to kit, from a topic-controlled corpus of monologues (166 speakers), to test for effects that are characteristic of priming phenomena: repetition, decay, and lexical boost. Our analysis found evidence for all three effects. Tokens that were relatively high and front tended to be followed by tokens that were also high and front; the repetition effect weakened with greater time between the prime and target; and the repetition effect was stronger if the prime and target belonged to (different tokens of) the same word. Contrary to our expectations, however, the cross-vowel effects suggest that the repetition effect responded not to the direction of vowel changes within the SFVS, but rather the peripherality of the tokens. We also found an interaction between priming behavior and gender, with stronger repetition effects among men than women. While these findings both indicate that priming manifests in continuous phonetic variation and provide further evidence that priming is among the factors providing structure to intraspeaker variation, they also challenge unitary accounts of priming phenomena.

Subphonemic Variation and Lexical Processing: Social and Stylistic Factors

Different pronunciation variants of the same word can facilitate lexical access, but they may be more or less effective primes depending on their phonological form, stylistic appropriateness, familiarity, and social prestige, suggesting that multiple phonological variants are encoded in the lexicon with varying strength. The current study investigated how subphonemic variation is encoded using a lexical decision task with cross-modal form priming. The results revealed that the magnitude of priming was mediated by stylistic and social properties of the auditory primes, including speaking style, talker dialect, and duration. These interactions provide evidence that phonetically reduced forms and forms that are not socially prestigious are not as robustly encoded in the lexicon as canonical forms and forms produced in prestigious varieties.

Unstressed Vowel Reduction Across Majorcan Catalan Dialects: Production and Spoken Word Recognition

This study investigates the production and auditory lexical processing of words involved in a patterned phonological alternation in two dialects of Catalan spoken on the island of Majorca, Spain. One of these dialects, that of Palma, merges /ɔ/ and /o/ as [o] in unstressed position, and it maintains /u/ as an independent category, [u]. In the dialect of Sóller, a small village, speakers merge unstressed /ɔ/, /o/, and /u/ to [u]. First, a production study asks whether the discrete, rule-based descriptions of the vowel alternations provided in the dialectological literature are able to account adequately for these processes: are mergers complete? Results show that mergers are complete with regards to the main acoustic cue to these vowel contrasts, that is, F1. However, minor differences are maintained for F2 and vowel duration. Second, a lexical decision task using cross-modal priming investigates the strength with which words produced in the phonetic form of the neighboring (versus one's own) dialect activate the listeners' lexical representations during spoken word recognition: are words within and across dialects accessed efficiently? The study finds that listeners from one of these dialects, Sóller, process their own and the neighboring forms equally efficiently, while listeners from the other one, Palma, process their own forms more efficiently than those of the neighboring dialect. This study has implications for our understanding of the role of lifelong linguistic experience on speech performance.

Effects of Lexical Competition and Dialect Exposure on Phonological Priming

A cross-modal lexical decision task was used to explore the effects of lexical competition and dialect exposure on phonological form priming. Relative to unrelated auditory primes, matching real word primes facilitated lexical decision for visual real word targets, whereas competing minimal pair primes inhibited lexical decision. These effects were robust across two English vowel pairs (mid-front and low-front) and for two listener groups (mono-dialectal and multi-dialectal). However, both the most robust facilitation and the most robust inhibition were observed for the mid-front vowel words with few phonological competitors for the mono-dialectal listener group. The mid-front vowel targets were acoustically more distinct than the low-front vowel targets, suggesting that acoustic-phonetic similarity leads to stronger lexical competition and less robust facilitation and inhibition. The multi-dialectal listeners had more prior exposure to multiple different dialects than the mono-dialectal group, suggesting that long-term exposure to linguistic variability contributes to a more flexible processing strategy in which lexical competition extends over a longer period of time, leading to less robust facilitation and inhibition.

Inhibitory phonetic priming: Where does the effect come from?

Both phonological and phonetic priming studies reveal inhibitory effects that have been interpreted as resulting from lexical competition between the prime and the target. We present a series of phonetic priming experiments that contrasted this lexical locus explanation with that of a prelexical locus by manipulating the lexical status of the prime and the target and the task used. In the related condition of all experiments, spoken targets were preceded by spoken primes that were phonetically similar but shared no phonemes with the target (/bak/-/dεt/). In Experiments 1 and 2, word and nonword primes produced an inhibitory effect of equal size in shadowing and same-different tasks respectively. Experiments 3 and 4 showed robust inhibitory phonetic priming on both word and nonword targets in the shadowing task, but no effect at all in a lexical decision task. Together, these findings show that the inhibitory phonetic priming effect occurs independently of the lexical status of both the prime and the target, and only in tasks that do not necessarily require the activation of lexical representations. Our study thus argues in favour of a prelexical locus for this effect.

The Contribution of Segmental and Tonal Information in Mandarin Spoken Word Processing

Two priming experiments examined the separate contribution of lexical tone and segmental information in the processing of spoken words in Mandarin Chinese. Experiment I contrasted four types of prime-target pairs: tone-and-segment overlap (ru4-ru4), segment-only overlap (ru3-ru4), tone-only overlap (sha4-ru4) and unrelated (qin 1 -ru4) in an auditory lexical decision task with 48 native Mandarin listeners. Experiment 2 further investigated the minimal segmental overlap needed to trigger priming when tonal information is present. Four prime-target conditions were contrasted: tone-and-segment overlap (ru4-ru4), only onset segment overlap (re4-ru4), only rime overlap (pu4-ru4) and unrelated (qin 1 -ru4) in an auditory lexical decision task with 68 native Mandarin listeners. The results showed significant priming effects when both tonal and segmental information overlapped or, although to a lesser extent, when only segmental information overlapped, with no priming found when only tones matched. Moreover, any partial segmental overlap, even with matching tonal cues, resulted in significant inhibition. These data clearly indicate that lexical tones are processed differently from segments, with syllabic structure playing a critical role. These findings are discussed in terms of the overall architecture of the processing system that emerges in Mandarin lexical access.

Phonological priming reflects lexical competition

A phonological relationship between a prime and a target produces facilitation when one or two initial phonemes are shared (low-similarity facilitation) but produces interference when more phonemes are shared (high-similarity interference; Slowiaczek & Hamburger, 1992). Although low-similarity facilitation appears to be a strategic effect (Goldinger, Luce, Pisoni, & Marcario, 1992), this result cannot generalize to high-similarity interference because the two effects are dissociated (Slowiaczek & Hamburger, 1992). In the present study, strategic processing in high-similarity interference was investigated. The phonological relatedness proportion (PRP) and the prime-target interstimulus interval (ISI) were varied in a shadowing experiment. Low-similarity facilitation was found only with a high PRP and long ISI, but high-similarity interference was found regardless of PRP and ISI. These results suggest that strategies influence low-similarity facilitation, but high-similarity interference reflects automatic processing.

Danger and usefulness are detected early in auditory lexical processing: evidence from electroencephalography

Visual emotionally charged stimuli have been shown to elicit early electrophysiological responses (e.g., Ihssen, Heim, & Keil, 2007; Schupp, Junghöfer, Weike, & Hamm, 2003; Stolarova, Keil, & Moratti, 2006). We presented isolated words to listeners, and observed, using generalized additive modeling, oscillations in the upper part of the delta range, the theta range (Bastiaansen & Hagoort, 2003), and the lower part of the alpha range related to degree of (rated) danger and usefulness (Wurm, 2007) starting around 150 ms and continuing to 350 ms post stimulus onset. A negative deflection in the oscillations tied to danger around 250-300 ms fits well with a similar negativity observed in the same time interval for visual emotion processing. Frequency and competitor effects emerged or reached maximal amplitude later, around or following the uniqueness point. The early effect of danger, long before the words' uniqueness points, is interpreted as evidence for the dual pathway theory of LeDoux (1996).

Word-types, not word-tokens, facilitate extraction of phonotactic sequences by adults

Phonotactics-the permissibility of sound sequences within a word-correspond to lexical statistics, but controversy persists over which statistics are being tracked. In this study, lexical type and token counts were compared as they contributed to phonotactic extraction from an artificial lexicon. Young-adult participants were familiarized with a set of CVCCVC nonwords contextualized as a lexicon of Martian animal names. The type and token frequencies of word-medial consonant sequences within those names were varied systematically. Participants then rated new nonwords, containing the same medial sequences, on a 7-point scale for similarity to the Martian animal names. Higher ratings only followed high type frequency familiarization conditions, suggesting that word-types drove phonotactic extraction. Additionally, participants reversed the typical preference for high frequency English sequences, likely because they rated nonwords according to their membership to an unknown language. This finding suggests cognitively separable tracking of artificial language statistics and preexisting representations.

An Event-Related Potential Study of Cross-modal Morphological and Phonological Priming

The current work investigated whether differences in phonological overlap between the past- and present-tense forms of regular and irregular verbs can account for the graded neurophysiological effects of verb regularity observed in past-tense priming designs. Event-related potentials were recorded from sixteen healthy participants who performed a lexical-decision task in which past-tense primes immediately preceded present-tense targets. To minimize intra-modal phonological priming effects, cross-modal presentation between auditory primes and visual targets was employed, and results were compared to a companion intra-modal auditory study (Justus, Larsen, de Mornay Davies, & Swick, 2008). For both regular and irregular verbs, faster response times and reduced N400 components were observed for present-tense forms when primed by the corresponding past-tense forms. Although behavioral facilitation was observed with a pseudopast phonological control condition, neither this condition nor an orthographic-phonological control produced significant N400 priming effects. Instead, these two types of priming were associated with a post-lexical anterior negativity (PLAN). Results are discussed with regard to dual- and single-system theories of inflectional morphology, as well as intra- and cross-modal prelexical priming.

Speech perception at the interface of neurobiology and linguistics

Speech perception consists of a set of computations that take continuously varying acoustic waveforms as input and generate discrete representations that make contact with the lexical representations stored in long-term memory as output. Because the perceptual objects that are recognized by the speech perception enter into subsequent linguistic computation, the format that is used for lexical representation and processing fundamentally constrains the speech perceptual processes. Consequently, theories of speech perception must, at some level, be tightly linked to theories of lexical representation. Minimally, speech perception must yield representations that smoothly and rapidly interface with stored lexical items. Adopting the perspective of Marr, we argue and provide neurobiological and psychophysical evidence for the following research programme. First, at the implementational level, speech perception is a multi-time resolution process, with perceptual analyses occurring concurrently on at least two time scales (approx. 20-80 ms, approx. 150-300 ms), commensurate with (sub)segmental and syllabic analyses, respectively. Second, at the algorithmic level, we suggest that perception proceeds on the basis of internal forward models, or uses an 'analysis-by-synthesis' approach. Third, at the computational level (in the sense of Marr), the theory of lexical representation that we adopt is principally informed by phonological research and assumes that words are represented in the mental lexicon in terms of sequences of discrete segments composed of distinctive features. One important goal of the research programme is to develop linking hypotheses between putative neurobiological primitives (e.g. temporal primitives) and those primitives derived from linguistic inquiry, to arrive ultimately at a biologically sensible and theoretically satisfying model of representation and computation in speech.

Priming and sentence context support listening to noise-vocoded speech by younger and older adults

Older adults are known to benefit from supportive context in order to compensate for age-related reductions in perceptual and cognitive processing, including when comprehending spoken language in adverse listening conditions. In the present study, we examine how younger and older adults benefit from two types of contextual support, predictability from sentence context and priming, when identifying target words in noise-vocoded sentences. In the first part of the experiment, benefit from context based on primarily semantic knowledge was evaluated by comparing the accuracy of identification of sentence-final target words that were either highly predictable or not predictable from the sentence context. In the second part of the experiment, benefit from priming was evaluated by comparing the accuracy of identification of target words when noise-vocoded sentences were either primed or not by the presentation of the sentence context without noise vocoding and with the target word replaced with white noise. Younger and older adults benefited from each type of supportive context, with the most benefit realized when both types were combined. Supportive context reduced the number of noise-vocoded bands needed for 50% word identification more for older adults than their younger counterparts.

Electrophysiological differentiation of phonological and semantic integration in word and sentence contexts

During auditory language comprehension, listeners need to rapidly extract meaning from the continuous speech-stream. It is a matter of debate when and how contextual information constrains the activation of lexical representations in meaningful contexts. Electrophysiological studies of spoken language comprehension have identified an event-related potential (ERP) that was sensitive to phonological properties of speech, which was termed the phonological mismatch negativity (PMN). With the PMN, early lexical processing could potentially be distinguished from processes of semantic integration in spoken language comprehension. However, the sensitivity of the PMN to phonological processing per se has been questioned, and it has additionally been suggested that the "PMN" is not separable from the N400, an ERP that is sensitive to semantic aspects of the input. Here, we investigated whether or not a separable PMN exists and if it reflects purely phonological aspects of the speech input. In the present experiment, ERPs were recorded from healthy young adults (N=24) while they listened to sentences and word lists, in which we manipulated semantic and phonological expectation and congruency of the final word. ERPs sensitive to phonological processing were elicited only when phonological expectancy was violated in lists of words, but not during normal sentential processing. This suggests a differential role of phonological processing in more or less meaningful contexts and indicates a very early influence of the overall context on lexical processing in sentences.

Neural aspects of cohort-size reduction during visual gating

In psycholinguistics, the coactivation of lexical candidates by partial input has received a lot of attention. More recently, psychophysiological studies have shed more light on this issue and identified two possible time windows in which effects of coactivation of lexical candidates can be observed in event-related potentials (ERPs). However, these studies cannot be used to disentangle effects of coactivation from the inhibition of candidates that do not match input. A new visual gating paradigm is presented, in which stimuli were visually presented letter by letter, decreasing the size of the cohort of lexical candidates as more letters are presented. Stimuli were created such that at the letter position of interest, the amount of coactivated candidates was kept constant while manipulating the size of the reduction of the cohort. The resulting ERPs indicate two components (frontal P2, and a left temporal late negativity) that scaled with cohort-size reduction. These results show that a visual gating paradigm can be used to disentangle coactivation of lexical candidates from inhibition of non-matching items, and that these processes are closely related to each other in time.

Reading spoken words: Orthographic effects in auditory priming

Three experiments examined the involvement of orthography in spoken word processing using a task - unimodal auditory priming with offset overlap - taken to reflect activation of prelexical representations. Two types of prime-target relationship were compared; both involved phonological overlap, but only one had a strong orthographic overlap (e.g., dream-gleam vs. scheme-gleam). In Experiment 1, which used lexical decision, phonological overlap facilitated target responses in comparison with an unrelated condition (e.g., stove-gleam). More importantly, facilitation was modulated by degree of orthographic overlap. Experiment 2 employed the same design as Experiment 1, but with a modified procedure aimed at eliciting swifter responses. Again, the phonological priming effect was sensitive to the degree of orthographic overlap between prime and target. Finally, to test whether this orthographic boost was caused by congruency between response type and valence of the prime-target overlap, Experiment 3 used a pseudoword detection task, in which participants responded "yes" to novel words and "no" to known words. Once again phonological priming was observed, with a significant boost in the orthographic overlap condition. These results indicate a surprising level of orthographic involvement in speech perception, and provide clear evidence for mandatory orthographic activation during spoken word recognition.

Does horse activate mother? Processing lexical tone in form priming

Lexical tone languages make up the majority of all known languages of the world, but the role of tone in lexical processing remains unclear. In the present study, four form priming experiments examined the role of Mandarin tones in constraining lexical activation and the time course of the activation. When a prime and a target were related directly in form (e.g., lou3 'hug'--lou2 'hall'), competitors that differed from the prime in tone failed to be activated, indicating the use of tonal information to distinguish between segmentally identical words. When a prime and a target were not form-related but were related through a third word that was not actually presented (e.g., lou3 'hug'--jian4zhu0 'building', where lou3 is form-related to lou2 'hall', which was semantically related to jian4zhu0), a mismatch in tone prevented activation of minimal tone pairs at 250ms interstimulus interval (ISI) but did not prevent activation at 50 ms ISI. These results indicate that tonal information is used on-line to reduce the number of activated candidates, but does not prevent the minimal tone pairs from being activated in the early phase of lexical activation.

Orthographic representations in spoken word priming: no early automatic activation

The current study investigated the modulation by orthographic knowledge of the final overlap phonological priming effect, contrasting spoken prime-target pairs with congruent spellings (e.g., 'carreau-bourreau', /karo/-/buro/) to pairs with incongruent spellings (e.g., 'zéro-bourreau', /zero/-/buro/). Using materials and designs aimed at reducing the impact of response biases or strategies, no orthographic congruency effect was found in shadowing, a speech recognition task that can be performed prelexically. In lexical decision, an orthographic effect occurred only when the processing environment reduced the prominence of phonological overlap and thus induced participants to rely on word spelling. Overall, the data do not support the assumption of early, automatic activation of orthographic representations during spoken word recognition.

The cascaded nature of lexical selection and integration in auditory sentence processing

An event-related brain potential experiment was carried out to investigate the temporal relationship between lexical selection and the semantic integration in auditory sentence processing. Participants were presented with spoken sentences that ended with a word that was either semantically congruent or anomalous. Information about the moment in which a sentence-final word could uniquely be identified, its isolation point (IP), was compared with the onset of the elicited N400 congruity effect, reflecting semantic integration processing. The results revealed that the onset of the N400 effect occurred prior to the IP of the sentence-final words. Moreover, the factor early or late IP did not affect the onset of the N400. These findings indicate that lexical selection and semantic integration are cascading processes, in that semantic integration processing can start before the acoustic information allows the selection of a unique candidate and seems to be attempted in parallel for multiple candidates that are still compatible with the bottom-up acoustic input.

The representation of polysemy: MEG evidence

Most words in natural language are polysemous, that is, they can be used in more than one way. For example, paper can be used to refer to a substance made out of wood pulp or to a daily publication printed on that substance. Although virtually every sentence contains polysemy, there is little agreement as to how polysemy is represented in the mental lexicon. Do different uses of polysemous words involve access to a single representation or do our minds store distinct representations for each different sense? Here we investigated priming between senses with a combination of behavioral and magnetoencephalographic measures in order to test whether different senses of the same word involve identity or mere formal and semantic similarity. Our results show that polysemy effects are clearly distinct from similarity effects bilaterally. In the left hemisphere, sense-relatedness elicited shorter latencies of the M350 source, which has been hypothesized to index lexical activation. Concurrent activity in the right hemisphere, on the other hand, peaked later for sense-related than for unrelated target stimuli, suggesting competition between related senses. The obtained pattern of results supports models in which the representation of polysemy involves both representational identity and difference: Related senses connect to same abstract lexical representation, but are distinctly listed within that representation.

Cleaving automatic processes from strategic biases in phonological priming

In a phonological priming experiment using spoken Dutch words, Dutch listeners were taught varying expectancies and relatedness relations about the phonological form of target words, given particular primes. They learned to expect that, after a particular prime, if the target was a word, it would be from a specific phonological category. The expectancy either involved phonological overlap (e.g., honk-vonk, "base-spark"; expected related) or did not (e.g., nest-galm, "nest-boom"; expected unrelated, where the learned expectation after hearing nest was a word rhyming in -alm). Targets were occasionally inconsistent with expectations. In these inconsistent expectancy trials, targets were either unrelated (e.g., honk-mest, "base-manure"; unexpected unrelated), where the listener was expecting a related target, or related (e.g., nest-pest, "nest-plague"; unexpected related), where the listener was expecting an unrelated target. Participant expectations and phonological relatedness were thus manipulated factorially for three types of phonological overlap (rhyme, one onset phoneme, and three onset phonemes) at three interstimulus intervals (ISIs; 50, 500, and 2,000 msec). Lexical decisions to targets revealed evidence of expectancy-based strategies for all three types of overlap (e.g., faster responses to expected than to unexpected targets, irrespective of phonological relatedness) and evidence of automatic phonological processes, but only for the rhyme and three-phoneme onset overlap conditions and, most strongly, at the shortest ISI (e.g., faster responses to related than to unrelated targets, irrespective of expectations). Although phonological priming thus has both automatic and strategic components, it is possible to cleave them apart.

Lexical competition in phonological priming: Assessing the role of phonological match and mismatch lengths between primes and targets

In five experiments, we examined lexical competition effects using the phonological priming paradigm in a shadowing task. Experiments 1A and 1B replicate and extend Slowiaczek and Hamburger's (1992) observation that inhibitory effects occur when the prime and the target share the first three phonemes (e.g., /bRiz/-/bRik/) but not when they share the first two phonemes (e.g., /bRepsilonz/-/bRik/). This observation suggests that lexical competition depends on the length of the phonological match between the prime and the target. However, Experiment 2 revealed that an overlap of two phonemes is sufficient to cause an inhibitory effect provided that the primes mismatched the targets only on the last phoneme (e.g., /b[symbol: see text]l/-/b[symbol: see text]t/). Conversely, with a three-phoneme overlap, no inhibition was observed in Experiment 3 when the primes mismatched the targets on the last two phonemes (e.g., /bagepsilont/-/baga3/). In Experiment 4, an inhibitory effect was again observed when the primes mismatched the targets on the last phoneme but not when they mismatched the targets on the last two phonemes when the time between the offset of overlapping segments in the primes and the onset of overlapping segments in the targets was controlled for. The data thus indicate that what essentially determines prime-target competition effects in word-form priming is the number of mismatching phonemes.

Effects of lexical competition on immediate memory span for spoken words

Current theories and models of the structural organization of verbal short-term memory are primarily based on evidence obtained from manipulations of features inherent in the short-term traces of the presented stimuli, such as phonological similarity. In the present study, we investigated whether properties of the stimuli that are not inherent in the short-term traces of spoken words would affect performance in an immediate memory span task. We studied the lexical neighbourhood properties of the stimulus items, which are based on the structure and organization of words in the mental lexicon. The experiments manipulated lexical competition by varying the phonological neighbourhood structure (i.e., neighbourhood density and neighbourhood frequency) of the words on a test list while controlling for word frequency and intra-set phonological similarity (family size). Immediate memory span for spoken words was measured under repeated and nonrepeated sampling procedures. The results demonstrated that lexical competition only emerged when a nonrepeated sampling procedure was used and the participants had to access new words from their lexicons. These findings were not dependent on individual differences in short-term memory capacity. Additional results showed that the lexical competition effects did not interact with proactive interference. Analyses of error patterns indicated that item-type errors, but not positional errors, were influenced by the lexical attributes of the stimulus items. These results complement and extend previous findings that have argued for separate contributions of long-term knowledge and short-term memory rehearsal processes in immediate verbal serial recall tasks.

Puzzle-solving science: the quixotic quest for units in speech perception

Although speech signals are continuous and variable, listeners experience segmentation and linguistic structure in perception. For years, researchers have tried to identify the basic building-block of speech perception. In that time, experimental methods have evolved, constraints on stimulus materials have evolved, sources of variance have been identified, and computational models have been advanced. As a result, the slate of candidate units has increased, each with its own empirical support. In this article, we endorse Grossberg's adaptive resonance theory (ART), proposing that speech units are emergent properties of perceptual dynamics. By this view, units only "exist" when disparate features achieve resonance, a level of perceptual coherence that allows conscious encoding. We outline basic principles of ART, then summarize five experiments. Three experiments assessed the power of social influence to affect phoneme-syllable competitions. Two other experiments assessed repetition effects in monitoring data. Together the data suggest that "primary" speech units are strongly and symmetrically affected by bottom-up and top-down knowledge sources.

An investigation of phonology and orthography in spoken-word recognition

The possible influence of initial phonological and/or orthographic information on spoken-word processing was examined in six experiments modelled after and extending the work Jakimik, Cole, and Rudnicky (1985). Following Jakimik et al., Experiment 1 used polysyllabic primes with monosyllabic targets (e.g., BUCKLE-BUCK/[symbol: see text]; MYSTERY-MISS,/[symbol: see text]). Experiments 2, 3, and 4 used polysyllabic primes and polysyllabic targets whose initial syllables shared phonological information (e.g., NUISANCE-NOODLE,/[symbol: see text]), orthographic information (e.g., RATIO-RATIFY,/[symbol: see text]), both (e.g., FUNNEL-FUNNY,/[symbol: see text]), or were unrelated (e.g., SERMON-NOODLE,/[symbol: see text]). Participants engaged in a lexical decision (Experiments 1, 3, and 4) or a shadowing (Experiment 2) task with a single-trial (Experiments 2 and 3) or subsequent-trial (Experiments 1 and 4) priming procedure. Experiment 5 tested primes and targets that varied in the number of shared graphemes while holding shared phonemes constant at one. Experiment 6 used the procedures of Experiment 2 but a low proportion of related trials. Results revealed that response times were facilitated for prime-target pairs that shared initial phonological and orthographic information. These results were confirmed under conditions when strategic processing was greatly reduced suggesting that phonological and orthographic information is automatically activated during spoken-word processing.

Revisiting bias effects in word-initial phonological priming

The phonological priming paradigm, in which participants respond to the second of 2 consecutively presented spoken words, has the potential to be a useful tool with which to study lexical processing. Concerns about response biases distorting the results have persisted since its introduction. This study explored the manifestation of biases by modifying the standard priming experiment such that the magnitude of priming effects using the same items could be compared at different points during the testing session. Four experiments investigated whether a recent dissociation of response biases and priming effects is evidence of lexical inhibition when the prime and target overlap by the first 3 word-initial phonemes (M. Hamburger & L. M. Slowiaczek, 1996). Biases were found in conditions previously thought to prevent their influence.

Phonological neighborhood effects in aphasic speech errors: spontaneous and structured contexts

The current study investigates the influence of phonological neighborhoods on the accuracy of speech production in aphasia by examining errors produced in both spontaneous and structured speech tasks. Characteristics of the phonological neighborhoods of spontaneously produced aphasic errors are compared to the neighborhood characteristics of correctly produced targets in a picture description task. Accuracy of picture naming is also examined with reference to the phonological neighborhood characteristics of the stimuli. Results show that frequency of occurrence and neighborhood density play a facilitative role in speech production, replicating findings from recent studies with normal subjects. It is argued that the results are most parsimoniously explained within an interactive activation framework of lexical access.

The influence of the lexicon on speech read word recognition: contrasting segmental and lexical distinctiveness

The neighborhood activation model (NAM; P. A. Luce & Pisoni, 1998) of spoken word recognition was applied to the problem of predicting accuracy of visual spoken word identification. One hundred fifty-three spoken consonant-vowel-consonant words were identified by a group of 12 college-educated adults with normal hearing and a group of 12 college-educated deaf adults. In both groups, item identification accuracy was correlated with the computed NAM output values. Analysis of subsets of the stimulus set demonstrated that when stimulus intelligibility was controlled, words with fewer neighbors were easier to identify than words with many neighbors. However, when neighborhood density was controlled, variation in segmental intelligibility was minimally related to identification accuracy. The present study provides evidence of a common spoken word recognition system for both auditory and visual speech that retains sensitivity to the phonetic properties of the input.

Universality versus language-specificity in listening to running speech

Recognizing spoken language involves automatic activation of multiple candidate words. The process of selection between candidates is made more efficient by inhibition of embedded words (like egg in beg) that leave a portion of the input stranded (here, b). Results from European languages suggest that this inhibition occurs when consonants are stranded but not when syllables are stranded. The reason why leftover syllables do not lead to inhibition could be that in principle they might themselves be words; in European languages, a syllable can be a word. In Sesotho (a Bantu language), however, a single syllable cannot be a word. We report that in Sesotho, word recognition is inhibited by stranded consonants, but stranded monosyllables produce no more difficulty than stranded bisyllables (which could be Sesotho words). Thisfinding suggests that the viability constraint which inhibits spurious embedded word candidates is not sensitive to language-specific word structure, but is universal.

A reason to rhyme: phonological and semantic influences on lexical access

During on-line language production, speakers rapidly select a sequence of words to express their desired meaning. The current study examines whether this lexical selection is also dependent on the existing activation of surface properties of the words. Such surface properties clearly matter in various forms of wordplay, including poetry and musical lyrics. The experiments in this article explore whether language processing more generally is sensitive to these properties. Two experiments examined the interaction between phonological and semantic features for written and verbal productions. In Experiment 1, participants were given printed sentences with a missing word, and were asked to generate reasonable completions. The completions reflected both the semantic and the surface features of the preceding context. In Experiment 2, listeners heard sentence contexts, and were asked to rapidly produce a word to complete the utterance. These spontaneous completions again incorporated surface features activated by the context. The results suggest that lexical access in naturalistic language processing is influenced by an interaction between the surface and semantic features of language.

Bias effects in facilitatory phonological priming

In four experiments, we examined the facilitation that occurs when spoken-word targets rhyme with preceding spoken primes. In Experiment 1, listeners' lexical decisions were faster to words following rhyming words (e.g., ramp-LAMP) than to words following unrelated primes (e.g., pink-LAMP). No facilitation was observed for nonword targets. Targets that almost rhymed with their primes (foils; e.g., bulk-SULSH) were included in Experiment 2; facilitation for rhyming targets was severely attenuated. Experiments 3 and 4 were single-word shadowing variants of the earlier experiments. There was facilitation for both rhyming words and nonwords; the presence of foils had no significant influence on the priming effect. A major component of the facilitation in lexical decision appears to be strategic: listeners are biased to say "yes" to targets that rhyme with their primes, unless foils discourage this strategy. The nonstrategic component of phonological facilitation may reflect speech perception processes that operate prior to lexical access.

Speech perception and spoken word recognition: past and present

OBJECTIVE

The scientific study of the perception of spoken language has been an exciting, prolific, and productive area of research for more than 50 yr. We have learned much about infants' and adults' remarkable capacities for perceiving and understanding the sounds of their language, as evidenced by our increasingly sophisticated theories of acquisition, process, and representation. We present a selective, but we hope, representative review of the past half century of research on speech perception, paying particular attention to the historical and theoretical contexts within which this research was conducted. Our foci in this review fall on three principle topics: early work on the discrimination and categorization of speech sounds, more recent efforts to understand the processes and representations that subserve spoken word recognition, and research on how infants acquire the capacity to perceive their native language. Our intent is to provide the reader a sense of the progress our field has experienced over the last half century in understanding the human's extraordinary capacity for the perception of spoken language.

Syntactic priming of nouns and verbs in Chinese

Syntactic priming of Chinese nouns and verbs was investigated in word recognition (cued shadowing of auditory targets) and production (picture naming). Disyllabic compound words were presented after syntactically congruent, incongruent, or neutral auditory contexts, with a zero delay between offset of the context and onset of the target. Significant priming was observed in both tasks, including facilitation as well as inhibition. Post hoc analyses showed that reaction times were also affected by sublexical variables that are especially relevant for Chinese, including syllable density (number of word types and tokens in the language with the same first or second syllable) and semantic transparency (whether the meaning of the whole word is predictable from the separate meanings of the two syllables within the compound). These patterns suggest competitive effects at the sublexical level. Implications for interactive models of lexical access are discussed.

Electrophysiological evidence for early contextual influences during spoken-word recognition: N200 versus N400 effects

An event-related brain potential experiment was carried out to investigate the time course of contextual influences on spoken-word recognition. Subjects were presented with spoken sentences that ended with a word that was either (a) congruent, (b) semantically anomalous, but beginning with the same initial phonemes as the congruent completion, or (c) semantically anomalous beginning with phonemes that differed from the congruent completion. In addition to finding an N400 effect in the two semantically anomalous conditions, we obtained an early negative effect in the semantically anomalous condition where word onset differed from that of the congruent completions. It was concluded that the N200 effect is related to the lexical selection process, where word-form information resulting from an initial phonological analysis and content information derived from the context interact.

Voornaam is not (really) a homophone: Lexical prosody and lexical access in Dutch

Four experiments examined Dutch listeners' use of suprasegmental information in spoken-word recognition. Isolated syllables excised from minimal stress pairs such as VOORnaam/voorNAAM could be reliably assigned to their source words. In lexical decision, no priming was observed from one member of minimal stress pairs to the other, suggesting that the pairs' segmental ambiguity was removed by suprasegmental information. Words embedded in nonsense strings were harder to detect if the nonsense string itself formed the beginning of a competing word, but a suprasegmental mismatch to the competing word significantly reduced this inhibition. The same nonsense strings facilitated recognition of the longer words of which they constituted the beginning, but again the facilitation was significantly reduced by suprasegmental mismatch. Together these results indicate that Dutch listeners effectively exploit suprasegmental cues in recognizing spoken words. Nonetheless, suprasegmental mismatch appears to be somewhat less effective in constraining activation than segmental mismatch.

Phonetic priming, neighborhood activation, and PARSYN

Perceptual identification of spoken words in noise is less accurate when the target words are preceded by spoken phonetically related primes (Goldinger, Luce, & Pisoni, 1989). The present investigation replicated and extended this finding. Subjects shadowed target words presented in the clear that were preceded by phonetically related or unrelated primes. In addition, primes were either higher or lower in frequency than the target words. Shadowing latencies were significantly longer for target words preceded by phonetically related primes, but only when the prime-target interstimulus interval was short (50 vs. 500 msec). These results demonstrate that phonetic priming does not depend on target degradation and that it affects processing time. We further demonstrated that PARSYN--a connectionist instantiation of the neighborhood activation model--accurately simulates the observed pattern of priming.

Only the shadower knows: comment on Hamburger and Slowiaczek (1996)

The phonological priming effect may reflect basic processes in spoken word perception and has thus been a central topic of recent research. In this journal, Hamburger and Slowiaczek (1996) reported phonological priming data collected in a shadowing task. They replicated a prior study (Slowiaczek & Hamburger, 1992), but added new procedures to minimize bias. After observing inhibitory priming in a "low-expectancy" condition, they concluded that facilitatory priming reflects perceptual/response bias, but that inhibitory priming reflects automatic processes of lexical access. This commentary critiques Hamburger and Slowiaczek's method and presents new data that demonstrate persistent biases in primed shadowing. I suggest that such biases reflect natural, context-sensitive listening strategies.

Phonological representations in postlingual deaf subjects using a multichannel cochlear implant

Our research is a first attempt to study phonological representations in postlingually deaf subjects using a multichannel cochlear implant. Before deafness, these subjects had developed normal language. The present study investigated how phonological representations are assessed through cochlear implant inputs by comparing priming within the auditory modality, and priming in a visual-auditory, cross-modal, condition. Two postlingually deafened adults participated in two lexical decision experiments where word primes were phonologically paired with a word target (e.g. vedette/dette), or a pseudoword target (e.g. banane/nane). The same word primes were also paired with non phonologically related target words (e.g. vedette/chat) and pseudowords (e.g. banane/repe). In addition, the same targets were used in phonologically-related pairs and in phonologically-unrelated ones. Results showed different priming effects for each patient. In one patient, priming was observed for word targets in the unimodal condition only. In the other patient, priming was observed for word targets and interference was observed for pseudoword targets in the cross-modal condition, whereas no effect was observed in the unimodal condition. In addition, this last patient made more errors for pseudowords than for words in the cross-modal condition. These results were interpreted as suggesting that lexical phonological representations participated to priming effects. Moreover, our results suggest that phonological word forms can be activated by visual primes via cochlear implants.

Signal detection comparisons of phonemic and phonetic priming: the flexible-bias problem

The phonemic priming effect may reflect the hidden dynamics of spoken word perception and has thus been a key topic of recent research. This investigation compared phonemic and phonetic priming (cf. Goldinger, Luce, Pisoni, & Marcario, 1992), using signal detection methods. Although these methods were intended to provide separate indices of sensitivity and bias changes, the results were more complex. Instead, phonemic priming engendered a flexible, trial-specific strategy that affected hits and false alarms (and thereby altered sensitivity) but also created behavioral changes indicative of a bias. Together with previous research, the results suggest that phonemic priming data must be interpreted with caution, and they underscore the limitations of signal detection analyses in priming research (Norris, 1995). However, if a researcher can anticipate the likely form a bias will assume, signal detection methods can reveal priming effects.