scholarly journals Lexical Access in the Face of Degraded Speech: Adapting to Moment by Moment Uncertainty

2021 ◽  
Author(s):  
Francis Xavier Smith ◽  
Bob McMurray

Listeners often process speech in adverse conditions. One challenge is spectral degradation, where information is missing from the signal. Lexical competition dynamics change when processing degraded speech, but it is unclear why and how these changes occur. We ask if these changes are driven solely by the quality of the input from the auditory periphery, or if these changes are modulated by cognitive mechanisms. Across two experiments, we used the visual world paradigm to investigate changes in lexical processing. Listeners heard different levels of noise-vocoded speech (4- or 15-channel vocoding) and matched the auditory input to pictures of a target word and its phonological competitors. In Experiment 1 levels of vocoding were either blocked together consistently or randomly interleaved from trial-to-trial. Listeners in the blocked condition showed more differentiation between the two levels of vocoding; this suggests that some level of learning is in effect to adapt to the varying levels of uncertainty in the input. Exploratory analyses suggested that when less intelligible speech is processed there is a cost to switching processing modes. In Experiment 2 levels of vocoding were always randomly interleaved. A visual cue was added to inform listeners of the level of difficulty of the upcoming speech. This was enough to attenuate the effects of interleaving as well as the switch cost. These experiments support a role for central processing in dealing with degraded speech. Listeners may be actively forming expectations about the level of degradation they will encounter and altering the dynamics of lexical access.

1970 ◽  
Vol 13 (1) ◽  
pp. 203-217 ◽  
Author(s):  
Isabelle Rapin ◽  
Peter Steinherz

A substantial part of reaction time (RT), the time elapsed between presentation of a stimulus and the subject’s response, reflects a central delay during which the brain processes the input and elaborates a response. Low stimulus intensity, inefficient central processing, and lack of motivation are among factors which prolong RT. RT was readily measured in 34 children, age 5½ and older, attending a school for the deaf. Rapid responses to light and light plus sound, and all responses to sound alone were rewarded. Four of twelve children initially unresponsive to sound learned to respond. When sound was attenuated, plots of RT gave information on the efficiency of responses to suprathreshold stimuli and warned that threshold was approaching 5–10 dB before it was reached. Such curves would increase the face validity of clinical audiometric threshold estimates. In severely deaf children, somatosensory stimulation by 500-Hz tones yielded RT curves and thresholds which were very similar to those obtained with aural presentation of the sound, casting doubt on the auditory origin of residual hearing in the low frequency range. Somatosensory stimulation by 1000- and 2000-Hz tones was rare.


2018 ◽  
Vol 71 (6) ◽  
pp. 1324-1339 ◽  
Author(s):  
Eva Commissaire ◽  
Séverine Casalis

This work aimed to investigate grapheme coding during sub-lexical processing and lexical access. Using the letter detection task in Experiment 1, we compared letter pairs that could be considered as a grapheme unit or not depending on context (referred to as weakly cohesive complex, e.g., an in chant vs cane) to real two-letter graphemes (highly cohesive complex, e.g., au in chaud) and single-letter graphemes (simple, e.g., a in place). Three experimental conditions were used, one of which was designed to prevent phonological influences. Data revealed that only highly cohesive complex graphemes were processed as units, not the weakly cohesive ones. The same pattern was found across experimental conditions in favor of an orthographic mechanism. In Experiments 2 and 3, a primed lexical decision task was used with two stimulus onset asynchronies (SOAs) and two different ranges of lexical frequency. We manipulated the number of graphemes removed from partial primes ( d**che vs do**he-DOUCHE) and relatedness. In contrast to Experiment 1, no evidence was provided in favor of a role of graphemes during lexical access. We suggest that graphemes can be conceived as sub-lexical orthographic units per se but can only be captured within a sub-lexical route to reading.


2017 ◽  
Vol 12 (1) ◽  
pp. 107-128 ◽  
Author(s):  
Maria De Martino ◽  
Giulia Bracco ◽  
Francesca Postiglione ◽  
Alessandro Laudanna

Abstract In some languages the grammatical gender of nouns can be probabilistically detected using formal cues; for instance, in Italian, the majority of feminine nouns end in ‘-a’(e.g., casa, ‘home’) and the majority of masculine nouns end in ‘-o’ (e.g., albero, ‘tree’). It has been hypothesized that the match/mismatch between the formal information of the suffix and the abstract grammatical information on gender affects lexical processing of nouns. An alternative account is that a default option available for gender poses constraints to mechanisms of lexical access for words exhibiting gender markers in the surface form. In the present study, nouns with highly predictive gender suffix (regular), nouns whose gender cannot be recovered from surface form (opaque) and nouns with misleading gender suffix (irregular) were compared in two reading aloud and two lexical decision experiments. Results confirmed that regular nouns are processed better than irregular nouns. No difference was detected between masculine and feminine opaque nouns. The results allow the conclusion that a formal gender feature (the gender orthographic regularity) is more likely to affect lexical processing of bare nouns than the activation of a gender default option.


2008 ◽  
Vol 29 (4) ◽  
pp. 553-584 ◽  
Author(s):  
ANNIE TREMBLAY

ABSTRACTThe objectives of this study are (a) to determine if native speakers of Canadian French at different English proficiencies can use primary stress for recognizing English words and (b) to specify how the second language (L2) learners' (surface-level) knowledge of L2 stress placement influences their use of primary stress in L2 word recognition. Two experiments were conducted: a cross-modal word-identification task investigating (a) and a vocabulary production task investigating (b). The results show that several L2 learners can use primary stress for recognizing English words, but only the L2 learners with targetlike knowledge of stress placement can do so. The results also indicate that knowing where primary stress falls in English words is not sufficient for L2 learners to be able to use stress for L2 lexical access. This suggests that the problem that L2 word stress poses for many native speakers of (Canadian) French is at the level of lexical processing.


2012 ◽  
Vol 36 (6) ◽  
pp. 457-467 ◽  
Author(s):  
Mathilde Fort ◽  
Elsa Spinelli ◽  
Christophe Savariaux ◽  
Sonia Kandel

The goal of this study was to explore whether viewing the speaker’s articulatory gestures contributes to lexical access in children (ages 5–10) and in adults. We conducted a vowel monitoring task with words and pseudo-words in audio-only (AO) and audiovisual (AV) contexts with white noise masking the acoustic signal. The results indicated that children clearly benefited from visual speech from age 6–7 onwards. However, unlike adults, the word superiority effect was not greater in the AV than the AO condition in children, suggesting that visual speech mostly contributes to phonemic—rather than lexical—processing during childhood, at least until the age of 10.


2015 ◽  
Vol 10 (3) ◽  
pp. 339-363 ◽  
Author(s):  
Nancy Azevedo ◽  
Ruth Ann Atchley ◽  
Eva Kehayia

The current research utilizes lexical decision within an oddball ERP paradigm to study early lexical processing. Nineteen undergraduate students completed four blocks of the oddball lexical decision task (Nonword targets among Words, Word targets among Nonwords, Word targets among Pseudowords, and Pseudoword targets among Words). We observed a reliable P3 ERP component in conditions where the distinction between rare and frequent trials could be made solely based on lexical status (Words among Nonwords and Nonwords among Words). We saw a reliable P3 to rare words among frequent pseudowords, but no P3 was observed when participants were asked to detect pseudowords in the context of frequent word stimuli. We argue that this observed modulation of the P3 results is consistent with psycholinguistic literature that suggests that two criteria are available during lexical access when performing a lexicality judgement, a non-lexical criterion that relies on global activation at the word level and a lexical criterion that relies on activation of a lexical representation (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001; Grainger & Jacobs, 1996).


2021 ◽  
Vol 66 (1) ◽  
pp. 45-60
Author(s):  
Kamil Długosz

Summary Research into cross-linguistic influence in L3 acquisition and processing has recently shown remarkable growth. However, still little is known about reverse interactions, i. e. the effects of L2 and L3 on L1. This study investigates visual cognate processing in Polish to determine whether lexical access in the dominant L1 is susceptible to the influence of the non-dominant L2 and L3. A group of 13 Polish learners of German and English participated in a lexical decision task in which both double and triple cognates were examined in comparison to control non-cognates and non-words. In line with the pattern found in most similar studies, the results reveal no cognate facilitation effect, thus indicating that L1 lexical access in multilinguals may also be selective with respect to L2 and L3. The theoretical consequences for L1 lexical processing in the multilingual mind are discussed.


2019 ◽  
Author(s):  
Eva Gutierrez-Sigut ◽  
Cristina Baus

The study of sign language has received increasing interest in the last decades. Within this growing field, research on sign language processing – including both comprehension and production – has also received a remarkable boost in recent years. At initial stages of research, efforts were concentrated on demonstrating universal aspects of language processing; thus, little attention was paid to the differences between modalities or to the specific aspects of the sign-modality. However, the wide recognition of sign languages as natural languages has supported a greater interest in furthering our understanding of modality specific factors (e.g., the use of proprioceptive and spatial information for phonological encoding or the greater potential for iconicity). This chapter offers a comprehensive overview of the most relevant studies of sign language comprehension and production that focus on the lexical level of processing. Results from behavioural studies, as well as evidence of similar neural substrates underlying speech and sign processing, have led to the widely accepted assumption that universal language processing principles can explain lexical access in both signed and spoken languages. However, although psycholinguistic and cognitive mechanisms as well as neural networks underlying speech and sign processing are strikingly similar, they are not identical. We propose that the study of the differences in processing of speech and signs can lead to a more complete picture of human language processing. Acknowledging these differences can also point researchers to factors influencing spoken language processing that might have been under-researched so far.


2021 ◽  
Vol 12 ◽  
Author(s):  
Kira Gor ◽  
Svetlana Cook ◽  
Denisa Bordag ◽  
Anna Chrabaszcz ◽  
Andreas Opitz

We propose the fuzzy lexical representations (FLRs) hypothesis that regards fuzziness as a core property of nonnative (L2) lexical representations (LRs). Fuzziness refers to imprecise encoding at different levels of LRs and interacts with input frequency during lexical processing and learning in adult L2 speakers. The FLR hypothesis primarily focuses on the encoding of spoken L2 words. We discuss the causes of fuzzy encoding of phonological form and meaning as well as fuzzy form-meaning mappings and the consequences of fuzzy encoding for word storage and retrieval. A central factor contributing to the fuzziness of L2 LRs is the fact that the L2 lexicon is acquired when the L1 lexicon is already in place. There are two immediate consequences of such sequential learning. First, L2 phonological categorization difficulties lead to fuzzy phonological form encoding. Second, the acquisition of L2 word forms subsequently to their meanings, which had already been acquired together with the L1 word forms, leads to weak L2 form-meaning mappings. The FLR hypothesis accounts for a range of phenomena observed in L2 lexical processing, including lexical confusions, slow lexical access, retrieval of incorrect lexical entries, weak lexical competition, reliance on sublexical rather than lexical heuristics in word recognition, the precedence of word form over meaning, and the prominence of detailed, even if imprecisely encoded, information about LRs in episodic memory. The main claim of the FLR hypothesis – that the quality of lexical encoding is a product of a complex interplay between fuzziness and input frequency – can contribute to increasing the efficiency of the existing models of LRs and lexical access.


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