This study examined the effects of bilingualism on speech recognition in noise performance of young normal-hearing Spanish-English bilinguals across several signal-to-noise ratios (SNR). The estimated signal-to-noise ratio needed for 50% correct recognition performance obtained for bilingual listeners was compared to young normal-hearing monolingual listeners of both English and Spanish. The estimated mean SNR needed for 50% correct recognition was significantly higher (i.e., poorer) for the bilingual than for the monolingual English listeners. The Spanish language performance of the bilingual listeners did not significantly differ from that of the monolingual Spanish listeners. The bilinguals were then divided into subgroups based on age of acquisition of the second language. Bilinguals were subdivided into early and later learners of English and further comparisons were made. The average estimated SNR needed for 50% correct recognition for the early bilinguals did not differ statistically from that of monolingual listeners in either the English or the Spanish language testing. The SNR obtained for 50% correct recognition of English words was significantly higher for the late bilinguals than for the monolingual English listeners. For Spanish words, the mean SNRs obtained for 50% correct recognition for the later bilinguals and the monolingual Spanish speakers did not differ statistically from one another. These results suggest that caution should be used when assessing speech-in-noise performance in the second language of bilingual patients because separate norms may be needed for this population. Age of acquisition of the second language should be considered as a confounding factor in speech-in-noise performance of bilingual listeners.

Thesis (Ph.D.)--University of Iowa, 2006. / Supervisor: J. Bruce Tomblin. Includes bibliographical references (leaves 118-129).

It has long been held that processing at the single word level during reading is automatic. However, research has recently begun to emerge that challenges this view. The literature surrounding the processing of emotion while recognizing printed words is limited, but some findings in the processing of emotion in faces suggest that negative stimuli (especially threat stimuli) promote quick and accurate processing. The purpose of the present experiments is to investigate whether negative emotionally-laden words are afforded priority processing in visual word recognition compared to positive emotionally-laden words. Two experiments are reported that manipulated the lexicality and valence of the target and distractor stimuli (Experiments 1 & 2), the validity of a spatial pre-cue (Experiments 1 & 2), and the presence of a distractor item (Experiment 2). Participants were asked to determine whether the target stimulus spelled a word or not. Response times on valid trials were faster compared to invalid trials, response times to negative emotionally-laden words were slower compared to positive emotionally-laden words, and the presence of a distractor item encouraged better focus on the target stimuli in the absence of any evidence that the valence of the distractor itself was processed. These results are consistent with the hypothesis that visual word recognition is not automatic given that processing benefited from the accurate direction of spatial attention. Furthermore, negative emotionally-laden words benefited equally compared to positive emotionally-laden words and therefore provide no evidence of automatic processing.

This thesis addresses the computation and organization of conceptual knowledge. Specifically, it focuses on the recruitment of concrete knowledge during single word reading using behavioural and electrophysiological methodologies. Chapters 1 and 2 assess how number of visual semantic features listed by participants as being part of a given concept influence the speed of word meaning computation, and its neural underpinnings, providing evidence for modality-specific neural organization. Chapter 3 assesses the flexibility of knowledge activation as a function of specific task constraints, suggesting a multi-faceted approach to semantic richness is needed. Chapter 4 describes a novel application of recent statistical advances to the analysis of real-time electrophysiological data, and highlights some limitations of standard analytical approaches. Chapter 5 assesses the real-time influence of several types of knowledge on the neuroelectric activity underlying concrete word meaning computation. A timecourse of sensory-based knowledge type activation is outlined. Finally, Chapter 6 describes a novel approach whereby real-time electrophysiological brain activity is used to predict the speed of semantic decision making, providing further evidence of a highly flexible, but finely structured, human semantic memory system.

This thesis addresses the computation and organization of conceptual knowledge. Specifically, it focuses on the recruitment of concrete knowledge during single word reading using behavioural and electrophysiological methodologies. Chapters 1 and 2 assess how number of visual semantic features listed by participants as being part of a given concept influence the speed of word meaning computation, and its neural underpinnings, providing evidence for modality-specific neural organization. Chapter 3 assesses the flexibility of knowledge activation as a function of specific task constraints, suggesting a multi-faceted approach to semantic richness is needed. Chapter 4 describes a novel application of recent statistical advances to the analysis of real-time electrophysiological data, and highlights some limitations of standard analytical approaches. Chapter 5 assesses the real-time influence of several types of knowledge on the neuroelectric activity underlying concrete word meaning computation. A timecourse of sensory-based knowledge type activation is outlined. Finally, Chapter 6 describes a novel approach whereby real-time electrophysiological brain activity is used to predict the speed of semantic decision making, providing further evidence of a highly flexible, but finely structured, human semantic memory system.

Förståelighet innebär hur väl lyssnaren förstår vad talaren menar (Hartelius & Lohmander, 2008). Barn med språkstörning har ofta en nedsatt förståelighet (Nettelbladt, 2007). Föreliggande studie syftar till att undersöka huruvida det föreligger någon skillnad mellan jämnåriga barns och vuxnas förståelse av ett svårförståeligt barn med språkstörning. Icke-familjära lyssnare genomförde lyssnarbedömningar i form av ordidentifiering. Lyssnarna bestod av tio vuxna (22-67 år) samt elva förskolebarn (4;1-5;6 år). Materialet de bedömde utgjordes av 23 ord, yttrade av en pojke (4;9 år) med diagnosen generell språkförsening (F80.2B). Materialet härrörde från spontantal och benämning av bilder från testet ”OrdRacet” (Eklund, 1996). De vuxna bedöarna fick äenskatta, på en skala från ett till fem, hur säkra de var i sin bedömning. Barnen uppfattade i genomsnitt 2,0±0,9 (8,7 %) ord korrekt och de vuxna 3,7±1,2 (16 %) ord korrekt. Denna skillnad var signifikant, p=.004. Skattning av säkerhet i bedömning för vuxna lyssnare gav ett genomsnittligt värde på 2,5±0,9. Studiens resultat visade att barn med språkstörning kan ha stora svårigheter att göra sig förstådda, särskilt bland jämnåriga barn. Därför är det av yttersta vikt att logopedisk intervention har målsättningen att förbättra barnens förståelighet. / The definition of intelligibility is how well listeners understand what speakers intend to say (Hartelius & Lohmander, 2008). Children with language impairment often have a reduced intelligibility (Nettelbladt, 2007). The aim of the present study was to investigate whether there is any difference between peers and adults in the understanding of an unintelligible child. 21 non-familiar listeners, ten adults (22-67 years) and eleven preschool children (4;1-5;6 years), carried out intelligibility assessments in terms of word recognition. The material consisted of 23 words uttered by a boy (4;9 years) diagnosed with language impairment, with both expressive and receptive difficulties. The material was derived from spontaneous speech and picture naming from the test "OrdRacet" (Eklund, 1996). The adult listeners were asked to rate their degree of confidence in judgement, on a five point scale. The children recognized at average 2.0±0.9 (8.7%) words correct and the adults 3.7±1.2 (16 %) words correct. This difference was statistically significant, p=.004. The adults’ listenerassessment of how sure they were in their word recognition gave a mean value of 2.5±0.9. The results indicated that children with language impairment may have great difficulties making themselves understood especially among peers. It is therefore important that intervention targets the intelligibility of their speech.

A central issue in word recognition is how readers retrieve and select the right representation among others in the mental lexicon. Recently, it has been claimed that recognition of individual words is influenced by the degree to which the words possess unique vs. shared letters or sounds relative to other words, that is, whether the words have few or several neighbors. Research on so-called neighborhood density effects advances understanding of the organization and operation of the mental lexicon. Orthographic neighborhood effects have been claimed to be facilitative, but recent studies of visual word recognition have led to a revised understanding of the nature of the orthographic neighborhood density effect. Through a reexamination of orthographic and phonological neighborhood density effects, the specific objective of the present research is to understand how orthographic and phonological representations interact across two different writing systems, i.e., English (an alphabetic orthography) and Chinese (a morphosyllabic orthography). The phenomena were studied using a joint behavioral (lexical decision) and neural imaging approach (near infrared spectroscopy, or NIRS). Orthographic and phonological (more, specifically, homophone) neighborhood density were manipulated in three lexical decision experiments with English and three with Chinese readers. After different sources of facilitative inter-lexicon connections were controlled, orthographic and phonological neighborhood density effects were found to be inhibitory in both writing systems. Inhibitory neighborhood density effects were also confirmed in two NIRS experiments of English and Chinese. The present research provided a better control of lexical characteristics than was the case in previous research on neighborhood effects and found a clear and consistent pattern of neighborhood density effects. This research supports interactive-activation models of word recognition rather than parallel-distributed models, given the evidence for lateral inhibition indexed by inhibitory neighborhood density effects. As such, the present study furthers the understanding of the organization and operation of the mental lexicon.

The present study aimed to investigate whether students¡¦ error types in word recognition would be contingent upon teaching strategies. Based on the perspectives of feature-matching theory in pattern recognition, it was predicted that, the phonetic compound strategy would reduce the error rate in the recognition of the picto-phonetic character, whereas the radical recognition strategy would lower the error rate in the recognition of the radical character. A quasi-experiment was conducted in which ninety-nine 4th-grade elementary students were assigned to three groups receiving phonetic compound strategy, radical recognition strategy, and distributed recognition strategy respectively. The dependent measures consisted of shape error rate and pronunciation error rate. The results showed that those students who received the phonetic compound strategy exhibited lower shape and pronunciation error rates of the picto-phonetic character than the students who received the distributed recognition strategy. On the other hand, those students who received the radical recognition strategy exhibited lower shape error rate of the radical character than the students who received the distributed recognition strategy. Regarding the interaction of character types and error types within a specific teaching strategy, for those students who received the phonetic compound strategy, the shape error rate of the picto-phonetic character was lower than the pronunciation error rate of the radical character. For those students who received the radical recognition strategy, both the shape and pronunciation error rates of the radical character were lower than those of the picto-phonetic character. The contingent relationships between teaching strategies and error types in word recognition were partially supported by empirical data. Possible reason would be that the pronunciation might produce a more prominent facilitation effect than that of the shape in Chinese word recognition. Finally, implications for teaching strategies in word recognition and directions for future research are also discussed.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Psychology, 2009. / Includes bibliographical references.

Thesis (M. Communication Pathology)--University of Pretoria, 2009. / Includes bibliographical references.