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

Across many languages from unrelated families, spoken-word recognition is subject to a constraint whereby potential word candidates must contain a vowel. This constraint minimizes competition from embedded words (e.g., in English, disfavoring win in twin because t cannot be a word). However, the constraint would be counter-productive in certain languages that allow stand-alone vowelless open-class words. One such language is Berber (where t is indeed a word). Berber listeners here detected words affixed to nonsense contexts with or without vowels. Length effects seen in other languages replicated in Berber, but in contrast to prior findings, word detection was not hindered by vowelless contexts. When words can be vowelless, otherwise universal constraints disfavoring vowelless words do not feature in spoken-word recognition.

Abstract

To examine whether lexically stored knowledge about spelling influences phoneme evaluation, we conducted three experiments with a low-level phonetic judgement task: phoneme goodness rating. In each experiment, listeners heard phonetic tokens varying along a continuum centred on /s/, occurring finally in isolated word or nonword tokens. An effect of spelling appeared in Experiment 1: Native English speakers’ goodness ratings for the best /s/ tokens were significantly higher in words spelled with S (e.g., bless) than in words spelled with C (e.g., voice). No such difference appeared when nonnative speakers rated the same materials in Experiment 2, indicating that the difference could not be due to acoustic characteristics of the S- versus C-words. In Experiment 3, nonwords with lexical neighbours consistently spelled with S (e.g., pless) versus with C (e.g., floice) failed to elicit orthographic neighbourhood effects; no significant difference appeared in native English speakers’ ratings for the S-consistent versus the C-consistent sets. Obligatory influence of lexical knowledge on phonemic processing would have predicted such neighbourhood effects; the findings are thus better accommodated by models in which phonemic decisions draw strategically upon lexical information.

Abstract

The way we listen to spoken language is tailored to the specific benefit of native-language speech input. Listening to speech in non-native languages can be significantly hindered by this native bias. Is it possible to determine the degree to which a listener is listening in a native-like manner? Promising indications of how this question may be tackled are provided by new research findings concerning the great flexibility that characterises listening to the L1, in online adjustment of phonetic category boundaries for adaptation across talkers, and in modulation of lexical dynamics for adjustment across listening conditions. This flexibility pays off in many dimensions, including listening in noise, adaptation across dialects, and identification of voices. These findings further illuminate the robustness and flexibility of native listening, and potentially point to ways in which we might begin to assess degrees of ‘native-likeness’ in this skill.

Abstract

Studies of spoken-word recognition have revealed that competition from embedded words differs in strength as a function of where in the carrier word the embedded word is found and have further shown embedding patterns to be skewed such that embeddings in initial position in carriers outnumber embeddings in final position. Lexico-statistical analyses show that this skew is highly attenuated in Japanese, a noninflectional language. Comparison of the extent of the asymmetry in the three Germanic languages English, Dutch, and German allows the source to be traced to a combination of suffixal morphology and vowel reduction in unstressed syllables.

Abstract

Around their first birthday infants begin to talk, yet they comprehend words long before. This study investigated the event-related potentials (ERP) responses of nine-month-olds on basic level picture-word pairings. After a familiarization phase of six picture-word pairings per semantic category, comprehension for novel exemplars was tested in a picture-word matching paradigm. ERPs time-locked to pictures elicited a modulation of the Negative Central (Nc) component, associated with visual attention and recognition. It was attenuated by category repetition as well as by the type-token ratio of picture context. ERPs time-locked to words in the training phase became more negative with repetition (N300-600), but there was no influence of picture type-token ratio, suggesting that infants have identified the concept of each picture before a word was presented. Results from the test phase provided clear support that infants integrated word meanings with (novel) picture context. Here, infants showed different ERP responses for words that did or did not align with the picture context: a phonological mismatch (N200) and a semantic mismatch (N400). Together, results were informative of visual categorization, word recognition and word-to-world-mappings, all three crucial processes for vocabulary construction.

Abstract

Infants’ ability to recognize words in continuous speech is vital for building a vocabulary.We here examined the amount and type
of exposure needed for 10-month-olds to recognize words. Infants first heard a word, either embedded within an utterance or in
isolation, then recognition was assessed by comparing event-related potentials to this word versus a word that they had not heard
directly before. Although all 10-month-olds showed recognition responses to words first heard in isolation, not all infants showed
such responses to words they had first heard within an utterance. Those that did succeed in the latter, harder, task, however,
understood more words and utterances when re-tested at 12 months, and understood more words and produced more words at
24 months, compared with those who had shown no such recognition response at 10 months. The ability to rapidly recognize the
words in continuous utterances is clearly linked to future language development.

Abstract

Children hear new words from many different talkers; to learn words most efficiently, they should be able to represent them independently of talker-specific pronunciation detail. However, do children know what the component sounds of words should be, and can they use that knowledge to deal with different talkers' phonetic realizations? Experiment 1 replicated prior studies on lexically guided retuning of speech perception in adults, with a picture-verification methodology suitable for children. One participant group heard an ambiguous fricative ([s/f]) replacing /f/ (e.g., in words like giraffe); another group heard [s/f] replacing /s/ (e.g., in platypus). The first group subsequently identified more tokens on a Simpie-[s/f]impie-Fimpie toy-name continuum as Fimpie. Experiments 2 and 3 found equivalent lexically guided retuning effects in 12- and 6-year-olds. Children aged 6 have all that is needed for adjusting to talker variation in speech: detailed and abstract phonological representations and the ability to apply them during spoken-word recognition.

Abstract

In British English, the phrase Canada aided can sound like Canada raided if the speaker
links the two vowels at the word boundary with an intrusive /r/. There are subtle phonetic
differences between an onset /r/ and an intrusive /r/, however. With cross-modal priming
and eye-tracking, we examine how native British English listeners and non-native
(Dutch) listeners deal with the lexical ambiguity arising from this language-specific
connected speech process. Together the results indicate that the presence of /r/ initially
activates competing words for both listener groups; however, the native listeners rapidly
exploit the phonetic cues and achieve correct lexical selection. In contrast, these
advanced L2 listeners to English failed to recover from the /r/-induced competition, and
failed to match native performance in either task. The /r/-intrusion process, which adds a
phoneme to speech input, thus causes greater difficulty for L2 listeners than connectedspeech
processes which alter or delete phonemes.

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 cross-modal priming experiments and two forced-choice identification experiments investigated the use of suprasegmental cues to stress in the recognition of spoken English words, by native (English-speaking) and non- native (Dutch) listeners. Previous results had indicated that suprasegmental information was exploited in lexical access by Dutch but not by English listeners. For both listener groups, recognition of visually presented target words was faster, in comparison to a control condition, after stress-matching spoken primes, either monosyllabic (mus- from MUsic /muSEum) or bisyl labic (admi- from ADmiral/admiRAtion). For native listeners, the effect of stress-mismatching bisyllabic primes was not different from that of control primes, but mismatching monosyllabic primes produced partial facilitation. For non-native listeners, both bisyllabic and monosyllabic stress-mismatching primes produced partial facilitation. Native English listeners thus can exploit suprasegmental information in spoken-word recognition, but information from two syllables is used more effectively than information from one syllable. Dutch listeners are less proficient at using suprasegmental information in English than in their native language, but, as in their native language, use mono- and bisyllabic information to an equal extent. In forced-choice identification, Dutch listeners outperformed native listeners at correctly assigning a monosyllabic fragment (e.g., mus-) to one of two words differing in stress.

Abstract

Rhythmic categories such as morae in Japanese or stress units in English play a role in the perception of spoken
language. We examined this role in Japanese, since recent evidence suggests that morae may intervene as
structural units in word recognition. First, we found that traditional puns more often substituted part of a mora
than a whole mora. Second, when listeners reconstructed distorted words, e.g. panorama from panozema, responses
were faster and more accurate when only a phoneme was distorted (panozama, panorema) than when a
whole CV mora was distorted (panozema). Third, lexical decisions on the same nonwords were better predicted
by duration and number of phonemes from nonword uniqueness point to word end than by number of morae. Our
results indicate no role for morae in early spoken-word processing; we propose that rhythmic categories constrain
not initial lexical activation but subsequent processes of speech segmentation and selection among word candidates.

Abstract

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). This finding suggests that the viability constraint which inhibits spurious embedded word candidates is not sensitive to language-specific word structure, but is universal.

Abstract

Becoming a native listener is the necessary precursor to becoming a native speaker. Babies in the first year of life undertake a remarkable amount of work; by the time they begin to speak, they have perceptually mastered the phonological repertoire and phoneme co-occurrence probabilities of the native language, and they can locate familiar word-forms in novel continuous-speech contexts. The skills acquired at this early stage form a necessary part of adult listening. However, the same native listening skills also underlie problems in listening to a late-acquired non-native language, accounting for why in such a case listening (an innate ability) is sometimes paradoxically more difficult than, for instance, reading (a learned ability).

Abstract

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.

Abstract

Spoken word recognition involves automatic activation of lexical candidates compatible with the perceived input. In running speech, words abut one another without intervening gaps, and syllable boundaries can mismatch with word boundaries. For instance, liaison in ’petit agneau’ creates a syllable beginning with a consonant although ’agneau’ begins with a vowel. In two cross-modal priming experiments we investigate how French listeners recognise words in liaison environments. These results suggest that the resolution of liaison in part depends on acoustic cues which distinguish liaison from non-liaison consonants, and in part on the availability of lexical support for a liaison interpretation.