Effects Of Neighborhood Density Research Articles

Phonetic imitation of coarticulatory vowel nasalization.

This study investigates the spontaneous phonetic imitation of coarticulatory vowel nasalization. Speakers produced monosyllabic words with a vowel-nasal sequence either from dense or sparse phonological neighborhoods in shadowing and word-naming tasks. During shadowing, they were exposed to target words that were modified to have either an artificially increased or decreased degree of coarticulatory vowel nasality. Increased nasality, which is communicatively more facilitative in that it provides robust predictive information about the upcoming nasal segment, was imitated more strongly during shadowing than decreased nasality. An effect of neighborhood density was also observed only in the increased nasality condition, where high neighborhood density words were imitated more robustly in early shadowing repetition. An effect of exposure to decreased nasality was observed during post-shadowing word-naming only. The observed imitation of coarticulatory nasality provides evidence that speakers and listeners are sensitive to the details of coarticulatory realization, and that imitation need not be mediated by abstract phonological representations. Neither a communicative account nor a representational account could single-handedly predict these observed patterns of imitation. As such, it is argued that these findings support both communicative and representational accounts of phonetic imitation.

Interactions in the neighborhood: Effects of orthographic and phonological neighbors on N400 amplitude.

The present study investigated effects of phonological and orthographic neighborhood density on event-related potentials, with an aim to better specify the factors that determine N400 amplitude in single word reading paradigms. We orthogonally manipulated the number of orthographic and phonological neighbors of words using the Levenshtein Distance metric (OLD20 and PLD20, respectively). The results showed opposite effects of phonological neighborhood density (PND) as a function of orthographic neighborhood density (OND). Larger N400 amplitudes were elicited by words with high PND compared with low PND when OND was high, and smaller N400 amplitudes were observed with high PND compared with low PND words when OND was low. We interpret these findings using the notion of cross-code consistency, according to which the compatibility of orthographic and phonological representations activated by a given word influences the process of recognizing that word. Words with similar numbers of orthographic and phonological neighbors have more consistent spellings and pronunciations across the neighborhood, and generate larger N400 amplitudes.

Is the time course of lexical activation and competition in spoken word recognition affected by adult aging? An event-related potential (ERP) study

Adult aging is associated with decreased accuracy for recognizing speech, particularly in noisy backgrounds and for high neighborhood density words, which sound similar to many other words. In the current study, the time course of neighborhood density effects in young and older adults was compared using event-related potentials (ERP) and behavioral responses in a lexical decision task for spoken words and nonwords presented either in quiet or in noise. Target items sounded similar either to many or to few other words (neighborhood density) but were balanced for the frequency of their component sounds (phonotactic probability). Behavioral effects of density were similar across age groups, but the event-related potential effects of density differed as a function of age group. For young adults, density modulated the amplitude of both the N400 and the later P300 or late positive complex (LPC). For older adults, density modulated only the amplitude of the P300/LPC. Thus, spreading activation to the semantics of lexical neighbors, indexed by the N400 density effect, appears to be reduced or delayed in adult aging. In contrast, effects of density on P300/LPC amplitude were present in both age groups, perhaps reflecting attentional allocation to items that resemble few words in the mental lexicon. The results constitute the first evidence that ERP effects of neighborhood density are affected by adult aging. The age difference may reflect either a unitary density effect that is delayed by approximately 150ms in older adults, or multiple processes that are differentially affected by aging.

Biological sensitivity to context: Cortisol awakening response moderates the effects of neighbourhood density on the development of adolescent externalizing problem behaviours

This four-year longitudinal study attempted to test person-environment interaction theory and biological sensitivity theory by assessing whether individuals’ biological stress activity CARAUCg (Cortisol Awakening Response Area Under the Curve with respect to ground) moderates the effects of neighbourhood density on the development of adolescent externalizing problem behaviours. Participants were 358 Dutch adolescents with a mean age of 15 years at the first measurement. Our analyses showed that CARAUCg moderated the effects of neighbourhood density on the level of parent-reported delinquency and aggression and adolescent self-reported delinquency. More specifically, for adolescents with high CARAUCg, higher neighbourhood density significantly predicted higher levels of parent-reported and adolescent self-reported delinquency and aggression, whereas the association was reversed or non-significant for adolescents with low CARAUCg. Our findings suggest that adolescents with different levels of CARAUCg respond differentially to the density of the neighbourhood they live in, supporting for person-environment interaction perspectives and biological sensitivity theory.

The phonological neighbourhood effect on short-term memory for order

ABSTRACTThere is a growing body of literature that suggests that long-term memory (LTM) and short-term memory (STM) structures that were once thought to be distinct are actually co-dependent, and that LTM can aid retrieval from STM. The mechanism behind this effect is commonly argued to act on item memory but not on order memory. The aim of the current study was to examine whether LTM could exert an influence on STM for order by examining an effect attributed to LTM, the phonological neighbourhood effect, in a task that reduced the requirement to retain item information. In Experiment 1, 18 participants completed a serial reconstruction task where neighbourhood density alternated within the lists. In Experiment 2, 22 participants completed a serial reconstruction task using pure lists of dense and sparse neighbourhood words. In Experiment 3, 22 participants completed a reconstruction task with both mixed and pure lists. There was a significant effect of neighbourhood density with better recall for dense than sparse neighbourhood words in pure lists but not in mixed lists. Results suggest that LTM exerts an influence prior to that proposed by many models of memory for order.

Spoken Language Activation Alters Subsequent Sign Language Activation in L2 Learners of American Sign Language.

A large body of literature has characterized unimodal monolingual and bilingual lexicons and how neighborhood density affects lexical access; however there have been relatively fewer studies that generalize these findings to bimodal (M2) second language (L2) learners of sign languages. The goal of the current study was to investigate parallel language activation in M2L2 learners of sign language and to characterize the influence of spoken language and sign language neighborhood density on the activation of ASL signs. A priming paradigm was used in which the neighbors of the sign target were activated with a spoken English word and compared the activation of the targets in sparse and dense neighborhoods. Neighborhood density effects in auditory primed lexical decision task were then compared to previous reports of native deaf signers who were only processing sign language. Results indicated reversed neighborhood density effects in M2L2 learners relative to those in deaf signers such that there were inhibitory effects of handshape density and facilitatory effects of location density. Additionally, increased inhibition for signs in dense handshape neighborhoods was greater for high proficiency L2 learners. These findings support recent models of the hearing bimodal bilingual lexicon, which posit lateral links between spoken language and sign language lexical representations.

The Influence of Orthographic Neighborhood Density and Word Frequency on Visual Word Recognition: Insights from RT Distributional Analyses.

The effects of orthographic neighborhood density and word frequency in visual word recognition were investigated using distributional analyses of response latencies in visual lexical decision. Main effects of density and frequency were observed in mean latencies. Distributional analyses additionally revealed a density × frequency interaction: for low-frequency words, density effects were mediated predominantly by distributional shifting whereas for high-frequency words, density effects were absent except at the slower RTs, implicating distributional skewing. The present findings suggest that density effects in low-frequency words reflect processes involved in early lexical access, while the effects observed in high-frequency words reflect late postlexical checking processes.

What can Neighbourhood Density effects tell us about word learning? Insights from a connectionist model of vocabulary development.

In this paper, we investigate the effect of neighbourhood density (ND) on vocabulary size in a computational model of vocabulary development. A word has a high ND if there are many words phonologically similar to it. High ND words are more easily learned by infants of all abilities (e.g. Storkel, 2009; Stokes, 2014). We present a neural network model that learns general phonotactic patterns in the exposure language, as well as specific word forms and, crucially, mappings between word meanings and word forms. The network is faster at learning frequent words, and words containing high-probability phoneme sequences, as human word learners are, but, independently of this, the network is also faster at learning words with high ND, and, when its capacity is reduced, it learns high ND words in preference to other words, similarly to late talkers. We analyze the model and propose a novel explanation of the ND effect, in which word meanings play an important role in generating word-specific biases on general phonological trajectories. This explanation leads to a new prediction about the origin of the ND effect in infants.

Lexical characteristics of Spanish and English words and the development of phonological awareness skills in Spanish-speaking language-minority children

The lexical restructuring model (LRM) is a theory that attempts to explain the developmental origins of phonological awareness (PA). According to the LRM, various characteristics of words should be related to the extent to which words are segmentally represented in the lexicon. Segmental representations of words allow children to access the parts of words needed to complete PA tasks. This study examined the relations between various lexical characteristics of Spanish and English words and the PA skills of Spanish-speaking language-minority children. Participants came from two independent samples of Spanish-speaking preschool children (Sample 1 N = 553, Sample 2 N = 600). For children in both samples, only phonotactic probability was related to children’s likelihood to respond correctly to Spanish PA items. Age of acquisition and word frequency were related to children’s likelihood to respond correctly to English PA items for children in both samples. Phonological neighborhood density and phonotactic probability were also related to children’s likelihood to respond correctly to English PA items; however, these effects were sample-specific. Children’s Spanish vocabulary knowledge moderated the effects of Spanish age of acquisition and word frequency on responses to Spanish PA items. Children’s English vocabulary knowledge moderated the effects of English phonological neighborhood density and phonotactic probability on responses to English PA items. These findings have implications for the development of PA assessments to be used with language-minority children.

The effect of phonotactic probability and neighbourhood density on pseudoword learning in 6- and 7-year-old children

The aim of this study was to examine the influence of phonotactic probability (PP) and neighbourhood density (ND) on pseudoword learning in 17 Dutch-speaking typically developing children (mean age 7;2). They were familiarized with 16 one-syllable pseudowords varying in PP (high vs low) and ND (high vs low) via a storytelling procedure. The participants were tested on their production and comprehension of the pseudowords on three testing sessions: immediately after training, after a consolidation period without further training and after a one week retention period during which one more training session was given. The results show that both in production and comprehension PP had a significant influence on pseudowords with low ND: pseudowords in the condition with converging characteristics (low PP – low ND) were learned significantly better than those in the high PP – low ND condition. No effect of PP was found for pseudowords high in ND. These results give cross-linguistic support for earlier English findings that convergent PP/ND (low PP – low ND) facilitates triggering word learning in children.

Many neighborhoods: Phonological and perceptual neighborhood density in lexical production and perception

Abstract We examine the relationship of lexical representations, pronunciation variation, and word recognition, by investigating effects of two lexical variables: Phonological Neighborhood Density (the number of words that can be formed by a single phoneme substitution, addition, or deletion from the target word), as well as a measure of the perceptual similarity of a target word to other words in the lexicon. We show that perceptual similarity to other words affects recognition, but not production. Phonological Neighborhood Density, on the other hand, affects both word durations and recognition accuracy (words with many neighbors shorten and are difficult recognition targets). We interpret our results as indicating that effects of Phonological Neighborhood Density on pronunciation are not generally due to perceptual similarity of the target to other words. Our results are consistent with a more general line of research demonstrating effects of ‘central’ processes on ‘peripheral’ processes such as articulation, as well as effects of modality-specific properties, such as auditory similarity and motor movements, on measures thought to tap central processes.

Positive density-dependent reproduction regulated by local kinship and size in an understorey tropical tree.

Global pollinator declines and continued habitat fragmentation highlight the critical need to understand reproduction and gene flow across plant populations. Plant size, conspecific density and local kinship (i.e. neighbourhood genetic relatedness) have been proposed as important mechanisms influencing the reproductive success of flowering plants, but have rarely been simultaneously investigated. We conducted this study on a continuous population of the understorey tree Miconia affinis in the Forest Dynamics Plot on Barro Colorado Island in central Panama. We used spatial, reproductive and population genetic data to investigate the effects of tree size, conspecific neighbourhood density and local kinship on maternal and paternal reproductive success. We used a Bayesian framework to simultaneously model the effects of our explanatory variables on the mean and variance of maternal viable seed set and siring success. Our results reveal that large trees had lower proportions of viable seeds in their fruits but sired more seeds. We documented differential effects of neighbourhood density and local kinship on both maternal and paternal reproductive components. Trees in more dense neighbourhoods produced on average more viable seeds, although this positive density effect was influenced by variance-inflation with increasing local kinship. Neighbourhood density did not have significant effects on siring success. This study is one of the first to reveal an interaction among tree size, conspecific density and local kinship as critical factors differentially influencing maternal and paternal reproductive success. We show that both maternal and paternal reproductive success should be evaluated to determine the population-level and individual traits most essential for plant reproduction. In addition to conserving large trees, we suggest the inclusion of small trees and the conservation of dense patches with low kinship as potential strategies for strengthening the reproductive status of tropical trees.

Visibility of speech articulation enhances auditory phonetic convergence.

Talkers automatically imitate aspects of perceived speech, a phenomenon known as phonetic convergence. Talkers have previously been found to converge to auditory and visual speech information. Furthermore, talkers converge more to the speech of a conversational partner who is seen and heard, relative to one who is just heard (Dias & Rosenblum Perception, 40, 1457-1466, 2011). A question raised by this finding is what visual information facilitates the enhancement effect. In the following experiments, we investigated the possible contributions of visible speech articulation to visual enhancement of phonetic convergence within the noninteractive context of a shadowing task. In Experiment 1, we examined the influence of the visibility of a talker on phonetic convergence when shadowing auditory speech either in the clear or in low-level auditory noise. The results suggest that visual speech can compensate for convergence that is reduced by auditory noise masking. Experiment 2 further established the visibility of articulatory mouth movements as being important to the visual enhancement of phonetic convergence. Furthermore, the word frequency and phonological neighborhood density characteristics of the words shadowed were found to significantly predict phonetic convergence in both experiments. Consistent with previous findings (e.g., Goldinger Psychological Review, 105, 251-279, 1998), phonetic convergence was greater when shadowing low-frequency words. Convergence was also found to be greater for low-density words, contrasting with previous predictions of the effect of phonological neighborhood density on auditory phonetic convergence (e.g., Pardo, Jordan, Mallari, Scanlon, & Lewandowski Journal of Memory and Language, 69, 183-195, 2013). Implications of the results for a gestural account of phonetic convergence are discussed.

Many neighbors are not silent. fMRI evidence for global lexical activity in visual word recognition.

Many neurocognitive studies investigated the neural correlates of visual word recognition, some of which manipulated the orthographic neighborhood density of words and nonwords believed to influence the activation of orthographically similar representations in a hypothetical mental lexicon. Previous neuroimaging research failed to find evidence for such global lexical activity associated with neighborhood density. Rather, effects were interpreted to reflect semantic or domain general processing. The present fMRI study revealed effects of lexicality, orthographic neighborhood density and a lexicality by orthographic neighborhood density interaction in a silent reading task. For the first time we found greater activity for words and nonwords with a high number of neighbors. We propose that this activity in the dorsomedial prefrontal cortex reflects activation of orthographically similar codes in verbal working memory thus providing evidence for global lexical activity as the basis of the neighborhood density effect. The interaction of lexicality by neighborhood density in the ventromedial prefrontal cortex showed lower activity in response to words with a high number compared to nonwords with a high number of neighbors. In the light of these results the facilitatory effect for words and inhibitory effect for nonwords with many neighbors observed in previous studies can be understood as being due to the operation of a fast-guess mechanism for words and a temporal deadline mechanism for nonwords as predicted by models of visual word recognition. Furthermore, we propose that the lexicality effect with higher activity for words compared to nonwords in inferior parietal and middle temporal cortex reflects the operation of an identification mechanism based on local lexico-semantic activity.

Phonological Neighborhood Competition Affects Spoken Word Production Irrespective of Sentential Context.

Two experiments examined the influence of phonologically similar neighbors on articulation of words' initial stop consonants in order to investigate the conditions under which lexically-conditioned phonetic variation arises. In Experiment 1, participants produced words in isolation. Results showed that the voice-onset time (VOT) of a target's initial voiceless stop was predicted by its overall neighborhood density, but not by its having a voicing minimal pair. In Experiment 2, participants read aloud the same targets after semantically predictive sentence contexts and after neutral sentence contexts. Results showed that, although VOTs were shorter in words produced after predictive contexts, the neighborhood density effect on VOT production persisted irrespective of context. These findings suggest that global competition from a word's neighborhood affects spoken word production independently of contextual modulation and support models in which activation cascades automatically and obligatorily among all of a selected target word's phonological neighbors during acoustic-phonetic encoding.

Listeners’ sensitivity to nasal coarticulation and its interactions with lexical neighborhood density

Previous research has shown that words from dense phonological neighborhoods, thus subject to greater lexical competition, are hyperarticulated (Wright, 2004; Munson and Solomon, 2004) and produced with a greater degree of coarticulation (Scarborough, 2013). The current study investigates listeners’ sensitivity to lexically conditioned degree of nasal coarticulation. If the basis of attested Neighborhood Density (ND) effects is listener-oriented (as suggested by Wright), listeners’ sensitivity to different degrees of coarticulation may be influenced by ND patterns as well. Forty-three native speakers of American English participated in a forced-choice discrimination task. The stimuli consisted of 32 monosyllabic words with nasal codas, and the degree of vowel nasality was natural or artificially increased or decreased. A Generalized Linear Mixed Effects regression was performed on Correct Response with Direction of Manipulation and ND as fixed factors. The model revealed a significant interaction of Direction and ND (p<0.001), where increased nasality was discriminated more correctly among high ND words while decreased nasality was discriminated more correctly among low ND words. This result shows that listeners are indeed sensitive to differences in degree of nasal coarticulation, and in ways that reflect neighborhood conditioned patterns.

The influence of word characteristics on the vocabulary of children with cochlear implants.

The goal of this study was to explore the effects of phonotactic probability, word length, word frequency, and neighborhood density on the words known by children with cochlear implants (CIs) varying in vocabulary outcomes in a retrospective analysis of a subset of data from a longitudinal study of hearing loss. Generalized linear mixed modeling was used to examine the effects of these word characteristics at 3 time points: preimplant, postimplant, and longitudinal follow-up. Results showed a robust effect of neighborhood density across group and time, whereas the effect of frequency varied by time. Significant effects of phonotactic probability or word length were not detected. Taken together, these findings suggest that children with CIs may be able to use spoken language structure in a manner similar to their normal hearing counterparts, despite the differences in the quality of the input. The differences in the effects of phonotactic probability and word length imply a difficulty in initiating word learning and limited working memory ability in children with CIs.

Word recognition and nonword repetition in children with language disorders: the effects of neighborhood density, lexical frequency, and phonotactic probability.

The effects of neighborhood density (ND) and lexical frequency on word recognition and the effects of phonotactic probability (PP) on nonword repetition (NWR) were examined to gain insight into processing at the lexical and sublexical levels in typically developing (TD) children and children with developmental language problems. Tasks measuring NWR and word recognition were administered to 5 groups of children: 2 groups of TD children (5 and 8 years old), children with specific language impairment (SLI), children with reading impairment (RI), and children with SLI+RI (all 7-8 years old). High ND had a negative effect on word recognition in the older TD children and in the children with RI only. There was no ND effect in the younger children or in the children with SLI, who all had lower receptive vocabulary scores than the age-matched TD children and the RI groups. For all groups, NWR items with low PP were more difficult to repeat than items with high PP. This effect was especially pronounced in children with RI. Both the stage of vocabulary development and the type of language impairment (SLI or RI) impact the way ND and PP affect word recognition and NWR.

Lexical competition in vowel articulation revisited: Vowel dispersion in the Easy/Hard database

A widely-cited study investigating effects of recognition difficulty on the phonetic realization of words (Wright, 2004). Factors of lexical competition in vowel articulation. In J. Local, R. Ogden & R. Temple (Eds.), Papers in laboratory phonology, Vol. VI (pp. 26–50)) reported that vowel dispersion, i.e. distance from the center of the talker's F1/F2 space, was greater in words that represented difficult recognition targets (‘hard’ words) than in easy recognition targets (‘easy’ words). The goal of the current study was to test whether that effect persisted when controlling for known other determinants of F1 and F2. A second goal was to test whether the pattern observed in the recordings analysed in Wright (2004) extended to all monophthongs in the set of recordings of which the words analysed in Wright (2004) formed a subset. We find that the dispersion difference between ‘easy’ and ‘hard’ words vowel dispersion is expected, given previous observations about effects of phonetic environment on vowel formants. When segmental context is taken into account, recognition difficulty fails to be predictive of vowel dispersion, both in the subset and in the larger database. An analysis of the fitted values of models of F1 and F2 based on consonantal factors (but not recognition difficulty) shows that the formant values predicted by those models separate vowels in “easy” and “hard” words in the manner observed in W2004. We discuss the implications for the effect of phonological neighbourhood density on language production, and for the relationship between lexical retrieval, auditory recognition difficulty and pronunciation variation.

Online Learning From Input Versus Offline Memory Evolution in Adult Word Learning: Effects of Neighborhood Density and Phonologically Related Practice

In this study, the authors investigated adult word learning to determine how neighborhood density and practice across phonologically related training sets influence online learning from input during training versus offline memory evolution during no-training gaps. Sixty-one adults were randomly assigned to learn low- or high-density nonwords. Within each density condition, participants were trained on one set of words and then were trained on a second set of words, consisting of phonological neighbors of the first set. Learning was measured in a picture-naming test. Data were analyzed using multilevel modeling and spline regression. Steep learning during input was observed, with new words from dense neighborhoods and new words that were neighbors of recently learned words (i.e., second-set words) being learned better than other words. In terms of memory evolution, large and significant forgetting was observed during 1-week gaps in training. Effects of density and practice during memory evolution were opposite of those during input. Specifically, forgetting was greater for high-density and second-set words than for low-density and first-set words. High phonological similarity, regardless of source (i.e., known words or recent training), appears to facilitate online learning from input but seems to impede offline memory evolution.