Publications by authors named "Lisa D Sanders"

This study investigated second language (L2-English) phonological processing in 31 Spanish-English bilingual, 6- to 8-year-old schoolchildren in an event-related potential (ERP) auditory pseudoword rhyming paradigm. In addition, associations between ERP effects and L2 proficiency as measured by standardized tests of receptive language and receptive vocabulary were explored. We found a classic posterior ERP rhyming effect that was more widely distributed in children with higher L2 proficiency in group analyses and was larger for children with better L2 proficiency in correlation analyses.

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Introduction: Spatial separation between competing speech streams reduces their confusion (informational masking), improving speech processing under challenging listening conditions. The precise stages of auditory processing involved in this benefit are not fully understood. This study used event-related potentials to examine the processing of target speech under conditions of informational masking and its spatial release.

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This study measured event-related brain potentials (ERPs) to test competing hypotheses regarding the effects of anger and race on early visual processing (N1, P2, and N2) and error recognition (ERN and Pe) during a sequentially primed weapon identification task. The first hypothesis was that anger would impair weapon identification in a biased manner by increasing attention and vigilance to, and decreasing recognition and inhibition of weapon identification errors following, task-irrelevant Black (compared to White) faces. Our competing hypothesis was that anger would facilitate weapon identification by directing attention toward task-relevant stimuli (i.

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Declines in spatial release from informational masking may contribute to the speech-processing difficulties that older adults often experience within complex listening environments. The present study sought to answer two fundamental questions: (1) Does spatial release from informational masking decline with age and, if so, (2) does age predict this decline independently of age-typical hearing loss? Younger (18-34 years) and older (60-80 years) adults with age-typical hearing completed a yes/no target-detection task with low-pass filtered noise-vocoded speech designed to reduce non-spatial segregation cues and control for hearing loss. Participants detected a target voice among two-talker masking babble while a virtual spatial separation paradigm [Freyman, Helfer, McCall, and Clifton, J.

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During early literacy skills development, rhyming is an important indicator of the phonological precursors required for reading. To determine if neural signatures of rhyming are apparent in early childhood, we recorded event-related potentials (ERPs) from 3- to 5-year-old, preliterate children (N = 62) in an auditory prime-target nonword rhyming paradigm (e.g.

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Dynamic attending theory predicts that attention is allocated hierarchically across time during processing of hierarchical rhythmic structures such as musical meter. ERP research demonstrates that attention to a moment in time modulates early auditory processing as evidenced by the amplitude of the first negative peak (N1) approximately 100 msec after sound onset. ERPs elicited by tones presented at times of high and low metric strength in short melodies were compared to test the hypothesis that hierarchically structured rhythms direct attention in a manner that modulates early perceptual processing.

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The precedence effect provides a novel way to examine the role of attention in auditory object formation. When presented with two identical sounds from different locations separated by a short stimulus onset asynchrony (SOA), listeners report a single auditory object at the location of the lead sound. When the SOA is above the echo threshold, listeners report hearing two auditory objects with different locations.

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The distal prosodic patterning established at the beginning of an utterance has been shown to influence downstream word segmentation and lexical access. In this study, we investigated whether distal prosody also affects word learning in a novel (artificial) language. Listeners were exposed to syllable sequences in which the embedded words were either congruent or incongruent with the distal prosody of a carrier phrase.

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Prosodic context several syllables prior (i.e., distal) to an ambiguous word boundary influences speech segmentation.

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Syntactic violations in speech and music have been shown to elicit an anterior negativity (AN) as early as 100 ms after violation onset and a posterior positivity that peaks at roughly 600 ms (P600/LPC). The language AN is typically reported as left-lateralized (LAN), whereas the music AN is typically reported as right-lateralized (RAN). However, several lines of evidence suggest syntactic processing of language and music rely on overlapping neural systems.

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Listeners often categorize phonotactically illegal sequences (e.g., /dla/ in English) as phonemically similar legal ones (e.

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Recent event-related potential (ERP) evidence demonstrates that adults employ temporally selective attention to preferentially process the initial portions of words in continuous speech. Doing so is an effective listening strategy since word-initial segments are highly informative. Although the development of this process remains unexplored, directing attention to word onsets may be important for speech processing in young children who would otherwise be overwhelmed by the rapidly changing acoustic signals that constitute speech.

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Under some conditions 4- and 5-year-old children can differentially process sounds from attended and unattended locations. In fact, the latency of spatially selective attention effects on auditory processing as measured with event-related potentials (ERPs) is quite similar in young children and adults. However, it is not clear if developmental differences in the polarity, distribution, and duration of attention effects are best attributed to acoustic characteristics, availability of non-spatial attention cues, task demands, or domain.

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Event-related potential (ERP) evidence indicates that listeners selectively attend to word onsets in continuous speech, but the reason for this preferential processing is unknown. The current study measured ERPs elicited by syllable onsets in an artificial language to test the hypothesis that listeners direct attention to word onsets because their identity is unpredictable. Both before and after recognition training, participants listened to a continuous stream of six nonsense words arranged in pairs, such that the second word in each pair was completely predictable.

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To gain information from complex auditory scenes, it is necessary to determine which of the many loudness, pitch, and timbre changes originate from a single source. Grouping sound into sources based on spatial information is complicated by reverberant energy bouncing off multiple surfaces and reaching the ears from directions other than the source's location. The ability to localize sounds despite these echoes has been explored with the precedence effect: Identical sounds presented from two locations with a short stimulus onset asynchrony (e.

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The ability to isolate a single sound source among concurrent sources and reverberant energy is necessary for understanding the auditory world. The precedence effect describes a related experimental finding, that when presented with identical sounds from two locations with a short onset asynchrony (on the order of milliseconds), listeners report a single source with a location dominated by the lead sound. Single-cell recordings in multiple animal models have indicated that there are low-level mechanisms that may contribute to the precedence effect, yet psychophysical studies in humans have provided evidence that top-down cognitive processes have a great deal of influence on the perception of simulated echoes.

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To understand the world around us, continuous streams of information including speech must be segmented into units that can be mapped onto stored representations. Recent evidence has shown that event-related potentials (ERPs) can index the online segmentation of sound streams. In the current study, listeners were trained to recognize sequences of three nonsense sounds that could not easily be rehearsed.

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Some of the most important information we encounter changes so rapidly that our perceptual systems cannot process all of it in detail. Spatially selective attention is critical for perception when more information than can be processed in detail is presented simultaneously at distinct locations. When presented with complex, rapidly changing information, listeners may need to selectively attend to specific times rather than to locations.

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Two masked priming experiments investigated the time-course of the activation of sub-phonemic information during visual word recognition. EEG was recorded as participants read targets with voiced and unvoiced final consonants (e.g.

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Spatially selective attention allows for the preferential processing of relevant stimuli when more information than can be processed in detail is presented simultaneously at distinct locations. Temporally selective attention may serve a similar function during speech perception by allowing listeners to allocate attentional resources to time windows that contain highly relevant acoustic information. To test this hypothesis, event-related potentials were compared in response to attention probes presented in six conditions during a narrative: concurrently with word onsets, beginning 50 and 100 ms before and after word onsets, and at random control intervals.

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Differential processing of local and global visual features is well established. Global precedence effects, differences in event-related potentials (ERPs) elicited when attention is focused on local versus global levels, and hemispheric specialization for local and global features all indicate that relative scale of detail is an important distinction in visual processing. Observing analogous differential processing of local and global auditory information would suggest that scale of detail is a general organizational principle of the brain.

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Behavioral and electrophysiological evidence suggests that the development of selective attention extends over the first two decades of life. However, much of this research may underestimate the attention abilities of young children. By providing strong, redundant attention cues, we show that sustained endogenous selective attention has similar effects on ERP indices of auditory processing in adults and children as young as 3 years old.

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In a dichotic listening paradigm, event-related potentials (ERPs) were recorded to linguistic and nonlinguistic probe stimuli embedded in 2 different narrative contexts as they were either attended or unattended. In adults, the typical N1 attention effect was observed for both types of probes: Probes superimposed on the attended narrative elicited an enhanced negativity compared to the same probes when unattended. Overall, this sustained attention effect was greater over medial and left lateral sites, but was more posteriorly distributed and of longer duration for linguistic as compared to nonlinguistic probes.

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Speech segmentation, breaking continuous streams of sound into units that can be recognized, is a necessary step in auditory language processing. To date, most studies of speech segmentation have been limited to behavioral measures that may not index online segmentation as it occurs when listening to natural speech. In the present study, we measured event-related potentials (ERPs) evoked by word-initial and word-medial syllables equated for loudness, length, and phonemic content.

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Behavioral and electrophysiological studies indicate that altered language experience has different effects on distinct subsystems within language. In this study, we recorded event-related potentials (ERPs) in native Japanese late-learners of English listening to English sentences. ERP indices of semantic processing, syntactic processing, and speech segmentation were compared and contrasted for native Japanese and previously tested native English speakers.

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