Rise time and formant transition duration in the discrimination of speech sounds: the Ba-Wa distinction in developmental dyslexia

Across languages, children with developmental dyslexia have a specific difficulty with the neural representation of the sound structure (phonological structure) of speech. One likely cause of their difficulties with phonology is a perceptual difficulty in auditory temporal processing (Tallal, 1980). Tallal (1980) proposed that basic auditory processing of brief, rapidly successive acoustic changes is compromised in dyslexia, thereby affecting phonetic discrimination (e.g. discriminating /b/ from /d/) via impaired discrimination of formant transitions (rapid acoustic changes in frequency and intensity). However, an alternative auditory temporal hypothesis is that the basic auditory processing of the slower amplitude modulation cues in speech is compromised (Goswami et al., 2002). Here, we contrast children's perception of a synthetic speech contrast (ba/wa) when it is based on the speed of the rate of change of frequency information (formant transition duration) versus the speed of the rate of change of amplitude modulation (rise time). We show that children with dyslexia have excellent phonetic discrimination based on formant transition duration, but poor phonetic discrimination based on envelope cues. The results explain why phonetic discrimination may be allophonic in developmental dyslexia (Serniclaes et al., 2004), and suggest new avenues for the remediation of developmental dyslexia.     

In the beginning was the rhyme? A reflection on Hulme,Hatcher, Nation,Brown, Adams,and Stuart (2002)

Phonological sensitivity at different grain sizes is a good predictor of reading acquisition in all languages. However, prior to any explicit tuition in alphabetic knowledge, phonological sensitivity develops at the larger grain sizes-syllables, onsets, and rimes-in all languages so far studied. There are also developmental differences in the grain size of lexical representations and reading strategies across orthographies. Phoneme-level skills develop fastest in children acquiring orthographically consistent languages with a simple syllabic (CV) structure, such as Finnish and Italian. For English, however, both "large" and "small" units are important for the successful acquisition of literacy.     

Mechanisms of Corporate Social Responsibility: The Moderating Role of Transformational Leadership

Literature reviews have repeatedly emphasized the need to further investigate relationships between corporate social responsibility (CSR) and micro-organizational variables. The present research attempts to address this call by examining the direct and indirect relationship between individual perceptions of CSR and employees’ organizational citizenship behaviors (OCBs). Multiphasic data from 207 workplace supervisor–subordinate dyads recruited from an online panel were analyzed to show that organizational identification mediated the relationship between CSR and OCBs. Furthermore, supervisor transformational leadership style moderated the mediation, such that the indirect effect of the organizational identification on the relationship between CSR and OCBs became nonsignificant under low transformational leadership. Based on these results, we make suggestions for using embeddedness programs to improve perceptions of CSR.     

Audiovisual perception of noise vocoded speech in dyslexic and non-dyslexic adults: The role of low-frequency visual modulations

Visual speech inputs can enhance auditory speech information, particularly in noisy or degraded conditions. The natural statistics of audiovisual speech highlight the temporal correspondence between visual and auditory prosody, with lip, jaw, cheek and head movements conveying information about the speech envelope. Low-frequency spatial and temporal modulations in the 2–7 Hz range are of particular importance. Dyslexic individuals have specific problems in perceiving speech envelope cues. In the current study, we used an audiovisual noise-vocoded speech task to investigate the contribution of low-frequency visual information to intelligibility of 4-channel and 16-channel noise vocoded speech in participants with and without dyslexia. For the 4-channel speech, noise vocoding preserves amplitude information that is entirely congruent with dynamic visual information. All participants were significantly more accurate with 4-channel speech when visual information was present, even when this information was purely spatio-temporal (pixelated stimuli changing in luminance). Possible underlying mechanisms are discussed.     

Fluency,phonology and morphology: a response to the commentaries on becoming literate in different languages

We are delighted at the range of issues raised in the commentaries. The breadth and scope of these serve to make obvious the need for an effective evidence base across languages if we are to optimize the teaching of reading. Our psycholinguistic grain size theory clearly did not pay sufficient attention to the role of morphology in decoding, nor to fluency. The commentaries also highlight the need for considering in more depth the intimate links between phonological and morphological development. All issues raised were highly germane to generating an adequate theoretical framework for the cross‐language collection of relevant evidence in different countries.     

Sensitivity to amplitude envelope rise time in infancy and vocabulary development at 3 years: A significant relationship

Here we report, for the first time, a relationship between sensitivity to amplitude envelope rise time in infants and their later vocabulary development. Recent research in auditory neuroscience has revealed that amplitude envelope rise time plays a mechanistic role in speech encoding. Accordingly, individual differences in infant discrimination of amplitude envelope rise times could be expected to relate to individual differences in language acquisition. A group of 50 infants taking part in a longitudinal study contributed rise time discrimination thresholds when aged 7 and 10 months, and their vocabulary development was measured at 3 years. Experimental measures of phonological sensitivity were also administered at 3 years. Linear mixed effect models taking rise time sensitivity as the dependent variable, and controlling for non‐verbal IQ, showed significant predictive effects for vocabulary at 3 years, but not for the phonological sensitivity measures. The significant longitudinal relationship between amplitude envelope rise time discrimination and vocabulary development suggests that early rise time discrimination abilities have an impact on speech processing by infants.     

Synesthesia and number cognition in children

Grapheme-color synesthesia, when achromatic digits evoke an experience of a specific color (photisms), has been shown to be consistent, involuntary, and linked with number concept in adults, yet there have been no comparable investigations with children. We present a systematic study of grapheme-color synesthesia in children aged between 7 and 15 years. Here we show that such children (but not children with phoneme-color synesthesia) experience involuntary difficulties in numerical tasks when digits are presented in colors incongruent with their photisms. Synesthesia in children may thus have important consequences for certain aspects of numerical cognition.     

Similarity relations among spoken words: The special status of rimes in English

This paper presents an analysis of the distribution of phonological similarity relations among monosyllabic spoken words in English. It differs from classical analyses of phonological neighborhood density (e.g., Luce &; Pisoni, 1998) by assuming that not all phonological neighbors are equal. Rather, it is assumed that the phonological lexicon has psycholinguistic structure. Accordingly, in addition to considering thenumber of phonological neighbors for any given word, it becomes important to consider thenature of these neighbors. If one type of neighbor is more dominant, neighborhood density effects may reflect levels of segmental representation other than the phoneme, particularly prior to literacy. Statistical analyses of the nature of phonological neighborhoods in terms ofrime neighbors (e.g.,hat/cat),consonant neighbors (e.g.,hat/hit), andlead neighbors (e.g.,hat/ham) were thus performed for all monosyllabic words in the Celex corpus (4,086 words). Our results show that most phonological neighbors are rime neighbors (e.g.,hat/cat) in English. Similar patterns were found when a corpus of words for which age-of-acquisition ratings were available was analyzed. The resultant database can be used as a tool for controlling and selecting stimuli when the role of lexical neighborhoods in phonological development and speech processing is examined.     

Is there conscious choice in directed mutation, phenocopies, and related phenomena? An answer based on quantum measurement theory

In a previous article (Goswami, 1997), it was suggested that an application of quantum measurement theory under the auspices of a monistic idealist ontology (that consciousness is the ground of being) can solve many difficult problems of neo-Darwinism, e.g., alternating rapid creativity and homeostasis observed in evolution and the directionality, origin, and nature of life. In this article, we propose an epigenetic quantum mechanism to explain the connection of developmental processes and evolution, as has been evidenced in such controversial phenomena as directed mutation and phenocopies. *** DIRECT SUPPORT *** A31BB026 00003     

The foundations of psychological understanding

In this paper, I review some recent submissions to Developmental Science that advance our understanding of psychological development. More and more submissions to the journal explore the origins of knowledge and, for psychological knowledge, such origins are multiple. Here I consider the contribution of mechanisms such as contingency detection, gaze following and gaze monitoring, social referencing and joint attention to emergent psychological understanding. I also consider infant understanding of goal-directed action, and the intimate connection between language acquisition and psychological development. The centrality of intention-reading skills to both language and social cognition is highlighted.