Publications

Abstract

Not only can the pitfalls that Firestone & Scholl (F&S) identify be generalised across multiple studies within the field of visual perception, but also they have general application outside the field wherever perceptual and cognitive processing are compared. We call attention to the widespread susceptibility of research on the perception of speech to versions of the same pitfalls.

Abstract

Speech perception involves prediction, but how is that prediction implemented? In cognitive models prediction has often been taken to imply that there is feedback of activation from lexical to pre-lexical processes as implemented in interactive-activation models (IAMs). We show that simple activation feedback does not actually improve speech recognition. However, other forms of feedback can be beneficial. In particular, feedback can enable the listener to adapt to changing input, and can potentially help the listener to recognise unusual input, or recognise speech in the presence of competing sounds. The common feature of these helpful forms of feedback is that they are all ways of optimising the performance of speech recognition using Bayesian inference. That is, listeners make predictions about speech because speech recognition is optimal in the sense captured in Bayesian models.

Abstract

L2 listening can involve the phantom activation of words which are not actually in the input. All spoken-word recognition involves multiple concurrent activation of word candidates, with selection of the correct words achieved by a process of competition between them. L2 listening involves more such activation than L1 listening, and we report two studies illustrating this. First, in a lexical decision study, L2 listeners accepted (but L1 listeners did not accept) spoken non-words such as groof or flide as real English words. Second, a priming study demonstrated that the same spoken non-words made recognition of the real words groove, flight easier for L2 (but not L1) listeners, suggesting that, for the L2 listeners only, these real words had been activated by the spoken non-word input. We propose that further understanding of the activation and competition process in L2 lexical processing could lead to new understanding of L2 listening difficulty.

Abstract

Speech processing by human listeners derives meaning from acoustic input via intermediate steps involving abstract representations of what has been heard. Recent results from several lines of research are here brought together to shed light on the nature and role of these representations. In spoken-word recognition, representations of phonological form and of conceptual content are dissociable. This follows from the independence of patterns of priming for a word's form and its meaning. The nature of the phonological-form representations is determined not only by acoustic-phonetic input but also by other sources of information, including metalinguistic knowledge. This follows from evidence that listeners can store two forms as different without showing any evidence of being able to detect the difference in question when they listen to speech. The lexical representations are in turn separate from prelexical representations, which are also abstract in nature. This follows from evidence that perceptual learning about speaker-specific phoneme realization, induced on the basis of a few words, generalizes across the whole lexicon to inform the recognition of all words containing the same phoneme. The efficiency of human speech processing has its basis in the rapid execution of operations over abstract representations.

Abstract

Speech recognition in noise is harder in second (L2) than first languages (L1). This could be because noise disrupts speech processing more in L2 than L1, or because L1 listeners recover better though disruption is equivalent. Two similar prior studies produced discrepant results: Equivalent noise effects for L1 and L2 (Dutch) listeners, versus larger effects for L2 (Spanish) than L1. To explain this, the latter experiment was presented to listeners from the former population. Larger noise effects on consonant identification emerged for L2 (Dutch) than L1 listeners, suggesting that task factors rather than L2 population differences underlie the results discrepancy.

Abstract

The acquisition of novel phonetic categories is hypothesized to be affected by the distributional properties of the input, the relation of the new categories to the native phonology, and the availability of supervision (feedback). These factors were examined in four experiments in which listeners were presented with novel categories based on vowels of Dutch. Distribution was varied such that the categorization depended on the single dimension duration, the single dimension frequency, or both dimensions at once. Listeners were clearly sensitive to the distributional information, but unidimensional contrasts proved easier to learn than multidimensional. The native phonology was varied by comparing Spanish versus American English listeners. Spanish listeners found categorization by frequency easier than categorization by duration, but this was not true of American listeners, whose native vowel system makes more use of duration-based distinctions. Finally, feedback was either available or not; this comparison showed supervised learning to be significantly superior to unsupervised learning.

Abstract

To segment continuous speech into its component words, listeners make use of language rhythm; because rhythm differs across languages, so do the segmentation procedures which listeners use. For each of stress-, syllable-and mora-based rhythmic structure, perceptual experiments have led to the discovery of corresponding segmentation procedures. In the case of mora-based rhythm, similar segmentation has been demonstrated in the otherwise unrelated languages Japanese and Telugu; segmentation based on syllable rhythm, however, has been previously demonstrated only for European languages from the Romance family. We here report two target detection experiments in which Korean listeners, presented with speech in Korean and in French, displayed patterns of segmentation like those previously observed in analogous experiments with French listeners. The Korean listeners' accuracy in detecting word-initial target fragments in either language was significantly higher when the fragments corresponded exactly to a syllable in the input than when the fragments were smaller or larger than a syllable. We conclude that Korean and French listeners can call on similar procedures for segmenting speech, and we further propose that perceptual tests of speech segmentation provide a valuable accompaniment to acoustic analyses for establishing languages' rhythmic class membership.

Abstract

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, butagain 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.

Abstract

We introduce the papers in this special issue by summarising the current major issues in spoken word recognition. We argue that a full understanding of the process of lexical access during speech comprehension will depend on resolving several key representational issues: what is the form of the representations used for lexical access; how is phonological information coded in the mental lexicon; and how is the morphological and semantic information about each word stored? We then discuss a number of distinct access processes: competition between lexical hypotheses; the computation of goodness-of-fit between the signal and stored lexical knowledge; segmentation of continuous speech; whether the lexicon influences prelexical processing through feedback; and the relationship of form-based processing to the processes responsible for deriving an interpretation of a complete utterance. We conclude that further progress may well be made by swapping ideas among the different sub-domains of the discipline.

Abstract

In two word-spotting experiments, Japanese listeners detected Japanese words faster in vowel contexts (e.g., agura, to sit cross-legged, in oagura) than in consonant contexts (e.g., tagura). In the same experiments, however, listeners spotted words in vowel contexts (e.g., saru, monkey, in sarua) no faster than in moraic nasal contexts (e.g., saruN). In a third word-spotting experiment, words like uni, sea urchin, followed contexts consisting of a consonant-consonant-vowel mora (e.g., gya) plus either a moraic nasal (gyaNuni), a vowel (gyaouni) or a consonant (gyabuni). Listeners spotted words as easily in the first as in the second context (where in each case the target words were aligned with mora boundaries), but found it almost impossible to spot words in the third (where there was a single consonant, such as the [b] in gyabuni, between the beginning of the word and the nearest preceding mora boundary). Three control experiments confirmed that these effects reflected the relative ease of segmentation of the words from their contexts.We argue that the listeners showed sensitivity to the viability of sound sequences as possible Japanese words in the way that they parsed the speech into words. Since single consonants are not possible Japanese words, the listeners avoided lexical parses including single consonants and thus had difficulty recognizing words in the consonant contexts. Even though moraic nasals are also impossible words, they were not difficult segmentation contexts because, as with the vowel contexts, the mora boundaries between the contexts and the target words signaled likely word boundaries. Moraic rhythm appears to provide Japanese listeners with important segmentation cues.

Abstract

Two word-spotting experiments are reported that examine whether the Possible-Word Constraint (PWC) is a language-specific or language-universal strategy for the segmentation of continuous speech. The PWC disfavours parses which leave an impossible residue between the end of a candidate word and any likely location of a word boundary, as cued in the speech signal. The experiments examined cases where the residue was either a CVC syllable with a schwa, or a CV syllable with a lax vowel. Although neither of these syllable contexts is a possible lexical word in English, word-spotting in both contexts was easier than in a context consisting of a single consonant. Two control lexical-decision experiments showed that the word-spotting results reflected the relative segmentation difficulty of the words in different contexts. The PWC appears to be language-universal rather than language-specific.

Abstract

Four cross-modal priming experiments in Spanish addressed the role of suprasegmental and segmental information in the activation of spoken words. Listeners heard neutral sentences ending with word fragments (e.g., princi-) and made lexical decisions on letter strings presented at fragment offset. Responses were compared for fragment primes that fully matched the spoken form of the initial portion of target words, versus primes that mismatched in a single element (stress pattern; one vowel; one consonant), versus control primes. Fully matching primes always facilitated lexical decision responses, in comparison to the control condition, while mismatching primes always produced inhibition. The respective strength of the contribution of stress, vowel, and consonant (one feature mismatch or more) information did not differ statistically. The results support a model of spoken-word recognition involving automatic activation of word forms and competition between activated words, in which the activation process is sensitive to all acoustic information relevant to the language’s phonology.

Abstract

In this paper, we use articulatory measures to determine whether Dutch schwa epenthesis is an abstract phonological process or a concrete phonetic process depending on articulatory timing. We examine tongue position during /l/ before underlying schwa and epenthetic schwa and in coda position. We find greater tip raising before both types of schwa, indicating light /l/ before schwa and dark /l/ in coda position. We argue that the ability of epenthetic schwa to condition the /l/ alternation shows that Dutch schwa epenthesis is an abstract phonological process involving insertion of some unit, and cannot be accounted for within Articulatory Phonology.

Abstract

There are currently a number of psycholinguistic models in which processing at a particular level of representation is characterized by the generation of multiple outputs, with resolution involving the use of information from higher levels of processing. Surprisingly, models with this architecture have been characterized as autonomous within the domain of word recognition and as interactive within the domain of sentence processing. We suggest that the apparent internal confusion is not, as might be assumed, due to fundamental differences between lexical and syntactic processing. Rather, we believe that the labels in each domain were chosen in order to obtain maximal contrast between a new model and the model or models that were currently dominating the field.

Abstract

There are currently a number of psycholinguistic models in which processing at a particular level of representation is characterized by the generation of multiple outputs, with resolution - but not generation - involving the use of information from higher levels of processing. Surprisingly, models with this architecture have been characterized as autonomous within the domain of word recognition but as interactive within the domain of sentence processing. We suggest that the apparent confusion is not, as might be assumed, due to fundamental differences between lexical and syntactic processing. Rather, we believe that the labels in each domain were chosen in order to obtain maximal contrast between a new model and the model or models that were currently dominating the field. The contradiction serves to highlight the inadequacy of a simple autonomy/interaction dichotomy for characterizing the architectures of current processing models.

Abstract

This chapter highlights that most language behavior consists of speaking and listening. The chapter also reveals differences and similarities between speaking and listening. The laboratory study of word production raises formidable problems; ensuring that a particular word is produced may subvert the spontaneous production process. Word production is investigated via slips and tip-of-the-tongue (TOT), primarily via instances of processing failure and via the technique of via the picture-naming task. The methodology of word production is explained in the chapter. The chapter also explains the phenomenon of interaction between various stages of word production and the process of speech recognition. In this context, it explores the difference between sound and meaning and examines whether or not the comparisons are appropriate between the processes of recognition and production of spoken words. It also describes the similarities and differences in the structure of the recognition and production systems. Finally, the chapter highlights the common issues in recognition and production research, which include the nuances of frequency of occurrence, morphological structure, and phonological structure.

Abstract

Strong and weak syllables in English can be distinguished on the basis of vowel quality, of stress, or of both factors. Critical for deciding between these factors are syllables containing unstressed unreduced vowels, such as the first syllable of automata. In this study 12 speakers produced sentences containing matched sets of words with initial vowels ranging from stressed to reduced, at normal and at fast speech rates. Measurements of the duration, intensity, F0, and spectral characteristics of the word-initial vowels showed that unstressed unreduced vowels differed significantly from both stressed and reduced vowels. This result held true across speaker sex and dialect. The vowels produced by one speaker were then cross-spliced across the words within each set, and the resulting words' acceptability was rated by listeners. In general, cross-spliced words were only rated significantly less acceptable than unspliced words when reduced vowels interchanged with any other vowel. Correlations between rated acceptability and acoustic characteristics of the cross-spliced words demonstrated that listeners were attending to duration, intensity, and spectral characteristics. Together these results suggest that unstressed unreduced vowels in English pattern differently from both stressed and reduced vowels, so that no acoustic support for a binary categorical distinction exists; nevertheless, listeners make such a distinction, grouping unstressed unreduced vowels by preference with stressed vowels

Abstract

Several models of spoken word recognition postulate that recognition is achieved via a process of competition between lexical hypotheses. Competition not only provides a mechanism for isolated word recognition, it also assists in continuous speech recognition, since it offers a means of segmenting continuous input into individual words. We present statistics on the pattern of occurrence of words embedded in the polysyllabic words of the English vocabulary, showing that an overwhelming majority (84%) of polysyllables have shorter words embedded within them. Positional analyses show that these embeddings are most common at the onsets of the longer word. Although both phonological and syntactic constraints could rule out some embedded words, they do not remove the problem. Lexical competition provides a means of dealing with lexical embedding. It is also supported by a growing body of experimental evidence. We present results which indicate that competition operates both between word candidates that begin at the same point in the input and candidates that begin at different points (McQueen, Norris, & Cutler, 1994, Noms, McQueen, & Cutler, in press). We conclude that lexical competition is an essential component in models of continuous speech recognition.

Abstract

Spoken utterances contain few reliable cues to word boundaries, but listeners nonetheless experience little difficulty identifying words in continuous speech. The authors present data and simulations that suggest that this ability is best accounted for by a model of spoken-word recognition combining competition between alternative lexical candidates and sensitivity to prosodic structure. In a word-spotting experiment, stress pattern effects emerged most clearly when there were many competing lexical candidates for part of the input. Thus, competition between simultaneously active word candidates can modulate the size of prosodic effects, which suggests that spoken-word recognition must be sensitive both to prosodic structure and to the effects of competition. A version of the Shortlist model ( D. G. Norris, 1994b) incorporating the Metrical Segmentation Strategy ( A. Cutler & D. Norris, 1988) accurately simulates the results using a lexicon of more than 25,000 words.

Abstract

In an earlier study, it was shown that listeners can use prosodic cues that predict where sentence stress will fall; phoneme-monitoring RTs are faster when the preceding prosody indicates that the word bearing the target will be stressed. Two experiments which further investigate this effect are described. In the first, it is shown that the duration of the closure preceding the release of the target stop consonant burst does not affect the RT advantage for stressed words. In the second, it is shown that fundamental frequency variation is not a necessary component of the prosodic variation that produces the predicted-stress effect. It is argued that sentence processing involves a very flexible use of prosodic information.

Abstract

Reaction time to detect a phoneme target in a sentence was found to be faster when the word in which the target occurred formed part of the semantic focus of the sentence. Focus was determined by asking a question before the sentence; that part of the sentence which comprised the answer to the sentence was assumed to be focussed. This procedure made it possible to vary position offocus within the sentence while holding all acoustic aspects of the sentence itself constant. It is argued that sentence understanding is facilitated by rapid identification of focussed information. Since focussed words are usually accented, it is further argued that the active search for accented words demonstrated in previous research should be interpreted as a search for semantic focus.