Effects Of Neighborhood Density Research Articles

Navigating neighborhoods: Density, size, and species diversity influences on tree survival in subtropical secondary forests

Neighborhood effects significantly impact individual tree survival through mechanisms of resource competition and species interactions within forest ecosystems. However, the specific impacts of these effects, particularly how biodiversity feedback affects survival across diverse life stages and spatial scales in subtropical secondary forests, remains insufficiently documented. To bridge this gap, we conducted an extensive analysis of neighborhood effects at different life stages and spatial scales in the subtropical secondary forests of the Wuyi Mountains in Southeast China, uncovering key insights into the community structure and dynamics. Our investigation over a five-year period encompassed all individuals within our study plot, quantifying effects of neighborhood density, individual size in resource competition, and species diversity in the neighborhood across various life stages. Employing mixed-effects models, we established quantitative relationships to assess the impact of these factors on tree survival at different spatial scales. Our findings confirmed that density dependence adversely affects sapling survival at smaller scales. As trees mature and spatial test scales expand, the detrimental effects of conspecific resource competition on individual mortality decrease, whereas heterospecific resource competition notably impairs survival probabilities in later successional stages, suggesting a shift from intraspecific to interspecific competition as the dominant influence on mortality during secondary succession. Additionally, we detected consistent patterns in conspecific and heterospecific density effects with increasing spatial scale. These effects transitioned from interspecific differences at smaller scales to more uniform positive effects at larger scales, which may be attributed to the strong spatial dependency of neighborhood density effects, potentially due to increased habitat heterogeneity. Furthermore, our study highlights the crucial role of heterospecific neighborhood effects in enhancing survival. We observed significant positive impacts of species diversity and heterospecific interactions on individual tree survival, particularly at smaller spatial scales during the sapling stage. Importantly, our research unveils significant variability in species sensitivity to different neighborhood effects, which change with life stage and spatial scale. This underscores the necessity of accounting for life stage variations among species and the influence of spatial heterogeneity on neighborhood effects such as density. Our findings delineate distinct competition mechanisms between the earlier and later phases of forest succession, emphasizing the distinctive recovery processes of subtropical secondary forests. These insights are essential for informing forest management and conservation strategies, ensuring a nuanced understanding of forest community dynamics.

Phonetic categorization in phonological lexical neighborhoods: Facilitatory and inhibitory effects

Phonetic processing, whereby the bottom-up speech signal is translated into higher-level phonological representations such as phonemes, has been demonstrated to be influenced by phonological lexical neighborhoods. Previous studies show facilitatory effects of lexicality and phonological neighborhood density on phonetic categorization. However, given the evidence for lexical competition in spoken word recognition, we hypothesize that there are concurrent facilitatory and inhibitory effects of phonological lexical neighborhoods on phonetic processing. In Experiments 1 and 2, participants categorized the onset phoneme in word-nonword and nonword-word acoustic continua. The results show that the target word of the continuum exhibits facilitatory lexical influences whereas rhyme neighbors inhibit phonetic categorization. The results support the hypothesis that sublexical phonetic processing is affected by multiple facilitatory and inhibitory lexical forces in the processing stream.

Measuring Phonological Complexity Using the Perfect Rhymes Dictionary (PeRDict)

This paper examines links between perfect rhymes and text readability and decoding using a measure of English rhymes called the Perfect Rhymes Dictionary (PeRDict). PeRDict is based on the Carnegie Mellon University Pronouncing Dictionary (the CMUdict) and provides rhyme counts for ∼48,000 words in English and for the most frequent 1,000, 2,500, 5,000, and 10,000 rhymes within the dictionary as measured by the Corpus of American English (COCA). Two assessments of PeRDICT are presented. The first examines the strength of rhyme features to predict text readability in conjunction with word neighborhood density effects reported by the English Lexicon Project (ELP) and a word frequency measure. The second examines the strength of rhyme features to predict word decoding in conjunction with word neighborhood effects and a word frequency measure. In both assessments, the number of rhymes per word was predictive of text or word processing beyond features related to word neighborhood effects and word frequency. Word rhyme counts performed more strongly in predicting text processing versus word processing.

Inhibitory and facilitative effects of lexical neighbors in spoken word recognition: The role of language experience

AbstractThe study evaluated whether the direction (inhibitory or facilitative) of the phonological neighborhood density effect in English spoken word recognition was modulated by the relative strength of competitor activation (neighborhood type) in two groups of English-dominant learners of Spanish who differed in language experience. Classroom learners and heritage learners of Spanish identified spoken English words from dense (e.g., BEAR) and sparse (e.g., BOAT) phonological neighborhoods presented in moderate noise. The phonological neighborhood was separately manipulated at word onset (cohort) and word offset (rhyme). Classroom learners were overall slower in recognizing spoken words from denser neighborhoods. Strongly active (onset) neighbors exerted inhibitory effects in both classroom and heritage learners. Critically, weakly active (offset) neighbors exerted inhibitory effects in classroom learners but facilitative effects in heritage learners. The results suggest that the activation of both within and cross-language neighbors should be considered in determining the direction of neighbor effects in bilingual lexical processing.

Neurophysiological effects of frequency, length, phonological neighborhood density, and iconicity on sign recognition.

Current theories on lexical recognition are mostly based on studies from spoken languages or their written forms. Much less is known about the process of lexical recognition in sign languages. This study aims to examine the neural correlates of sign recognition by investigating the effects of lexical frequency, length, phonological neighborhood density, and iconicity during Chinese Sign Language comprehension. Twenty-two deaf signers viewed a set of sign videos that varied in the 4 lexical properties and decided if they referred to animals, while event-related potential responses were recorded. Data were analyzed through linear mixed-effects models with the lexical variables treated as continuous measures. The results showed that frequency modulated ERP amplitude as early as around 200 ms and in the late N400 time frame. Sign length invoked effects throughout the process, starting from 200 ms and pertaining to the last epoch. Neighborhood density effects were also observed early around 200 ms and later on the N400 and late positive complex (LPC). Iconicity produced robust effects on the N400 and LPC amplitude. Lexical frequency, length, and neighborhood density influence the neural dynamics of sign recognition in a similar way as to spoken words. Iconicity can confer a processing advantage due to closer form-meaning mappings. The results indicate that lexical recognition engages some mechanisms that are universal across the signed and spoken modality, but it can also be regulated by modality-specific properties such as the prevalent iconicity in sign languages.

Investigating the effects of phonological neighborhood density, word frequency, and phoneme confusability on the English word recognition by native speakers of Japanese

This study aims to bridge the gap between previous research on the impact of phonological neighborhood density on word identification, which did not consider phoneme confusability, and studies on phoneme identification and discrimination, which did not account for the effects of phonological neighborhood density. Native Japanese listeners participated in this study, where they were tasked with identifying monosyllabic and disyllabic English words. The words varied in both phonological neighborhood density and word frequency and were produced by native speakers of American English and Japanese. Participants responded by typing the words they heard. The findings of this study indicated that there were no significant effects of phonological neighborhood density on word identification. However, frequent words were identified with greater accuracy compared to infrequent words. Moreover, words produced by native speakers of American English were more accurately identified than those produced by Japanese speakers. Japanese listeners' inaccurate perception of phonemes has resulted in word identification errors in both dense and sparse phonological neighborhoods. For example, they often mistakenly identify /l/ as /r/ and vice versa. Low and central vowels /æ, ɑ, ʌ/ are frequently misidentified as one another. These confusions are commonly observed among Japanese learners of English.

On choosing the vehicles of metaphors 2.0: the interactive effects of semantic neighborhood density and body-object interaction on metaphor production.

In a metaphor, such as language is a bridge, two distinct concepts known as the topic (i.e., language) and vehicle (i.e., bridge) are juxtaposed to produce figurative meaning. Previous work demonstrated that, when creating metaphors, participants choose vehicles that are concrete, rather than abstract, and are also a moderate semantic distance away from the topic. However, little is known about the semantic representations underlying metaphor production beyond topic-vehicle semantic distance and vehicle concreteness. Here, we studied the role of two semantic richness variables in metaphor production - semantic neighborhood density (SND), which measures the proximity of a word and its associations in semantic space, and body-object interaction (BOI), which reflects the ease with which a human body can motorically interact with a word's referent. In each trial, participants were presented with an abstract topic, such as miracle, and were instructed to make an apt and comprehensible metaphor by choosing a vehicle word (e.g., lighthouse). All of the topics were abstract but half were high-SND (from dense semantic neighborhoods) and half were low-SND (from sparse semantic neighborhoods). Similarly, half of the potential vehicle words were either high or low in SND and also differed on BOI such that half were high-BOI (e.g., bicycle), whereas half were low-BOI (e.g., rainbow). We observed a three-way interaction such that participants selected low-BOI, rather than high-BOI, vehicle words when topics or vehicles were high-SND. We interpret this finding to suggest that participants attempt to reduce the overall semantic richness of their created metaphors.

Native and foreign language orthotactic probability and neighborhood density in word learning

Abstract Laboratory studies on word learning in a foreign language (L2) have identified several variables involved in the learning process, key amongst them the orthotactic probability and neighborhood density of new words relative to learners’ native (L1) lexicons. More recently, learners’ sensitivity to orthotactic probability and neighborhood density relative to their developing L2 lexicons has come into focus. Past studies on word learning have largely focused on early stages of learning, in controlled studies spanning hours or days. Few studies have considered large corpora of ‘real-life’ learning data, spanning several weeks. In this study, we validate past findings outside of controlled laboratory conditions, by analyzing a dataset collected from Duolingo (Settles et al., 2018), a popular language learning app. Effects of orthotactic probability and neighborhood density observed in controlled studies persist under uncontrolled, big-data conditions for learners of Spanish, but not French. As learning progresses, we observe a previously unreported reversal of the effects of L1 orthotactic probability and neighborhood density, challenging theoretical models of word learning. Finally, we confirm the importance of orthotactic probability and neighborhood density relative to learners’ developing L2 Spanish lexicons, lending support to theories which posit that the same processes underly both L1 and L2 acquisition.

Disentangling the Role of Biphone Probability From Neighborhood Density in the Perception of Nonwords.

In six experiments we explored how biphone probability and lexical neighborhood density influence listeners' categorization of vowels embedded in nonword sequences. We found independent effects of each. Listeners shifted categorization of a phonetic continuum to create a higher probability sequence, even when neighborhood density was controlled. Similarly, listeners shifted categorization to create a nonword from a denser neighborhood, even when biphone probability was controlled. Next, using a visual world eye-tracking task, we determined that biphone probability information is used rapidly by listeners in perception. In contrast, task complexity and irrelevant variability in the stimuli interfere with neighborhood density effects. These results support a model in which both biphone probability and neighborhood density independently affect word recognition, but only biphone probability effects are observed early in processing.

Lexical Characteristics of the Speech Intelligibility Test: Effects on Transcription Intelligibility for Speakers With Multiple Sclerosis and Parkinson's Disease.

Lexical characteristics of speech stimuli can significantly impact intelligibility. However, lexical characteristics of the widely used Speech Intelligibility Test (SIT) are unknown. We aimed to (a) define variation in neighborhood density, word frequency, grammatical word class, and type-token ratio across a large corpus of SIT sentences and tests and (b) determine the relationship of lexical characteristics to speech intelligibility in speakers with multiple sclerosis (MS), Parkinson's disease (PD), and neurologically healthy controls. Using an extant database of 92 speakers (32 controls, 30 speakers with MS, and 30 speakers with PD), percent correct intelligibility scores were obtained for the SIT. Neighborhood density, word frequency, word class, and type-token ratio were calculated and summed for each of the 11 sentences of each SIT test. The distribution of each characteristic across SIT sentences and tests was examined. Linear mixed-effects models were performed to assess the relationship between intelligibility and the lexical characteristics. There was large variability in the distribution of lexical characteristics across this large corpus of SIT sentences and tests. Modeling revealed a relationship between intelligibility and the lexical characteristics, with word frequency and word class significantly contributing to the model. Three primary findings emerged: (a) There was considerable variability in lexical characteristics both within and across the large corpus of SIT tests; (b) there was not a robust association between intelligibility and the lexical characteristics; and (c) findings from a study demonstrating an effect of neighborhood density and word frequency on intelligibility were replicated. Clinical and research implications of the findings are discussed, and three exemplar SIT tests systematically controlling for neighborhood density and word frequency are provided.

The effects of lexical frequency and homophone neighborhood density on incomplete tonal neutralization.

We investigated the effects of lexical frequency and homophone neighborhood density on the acoustic realization of two neutralizing falling tones in Dalian Mandarin Chinese. Monosyllabic morphemes containing the target tones (Tone 1 and Tone 4) were produced by 60 native speakers from two generations (middle-aged vs. young). The duration of tone-bearing syllable rhymes, as well as the F0 curves and velocity profiles of the lexical tones were quantitatively analyzed via linear mixed-effects modeling and functional data analysis. Results showed no durational difference between T1 and T4. However, the F0 contours of the two falling tones were incompletely neutralized for both young and middle-aged speakers. Lexical frequency showed little effect on the incomplete tonal neutralization; there were significant differences in the turning point of the two falling tones in syllables with both high and low lexical frequency. However, homophone neighborhood density showed an effect on the incomplete neutralization between the two falling tones, reflected in significant differences in the slope and turning point of the F0 velocity profiles between the two tones carried by syllables with low density but not with high density. Moreover, homophone neighborhood density also affected the duration, the turning point of F0 curves, and velocity profiles of the T1- and T4-syllables. These results are discussed with consideration of social phonetic variations, the theory of Hypo- and Hyper-articulation (H&H), the Neighborhood Activation Model, and communication-based information-theoretic accounts. Collectively, these results broaden our understanding of the effects that lexical properties have on the acoustic details of lexical tone production and tonal sound changes.

Electrophysiological patterns of visual word recognition in deaf and hearing readers: an ERP mega-study

ABSTRACT Deaf and hearing readers have different access to spoken phonology which may affect the representation and recognition of written words. We used ERPs to investigate how a matched sample of deaf and hearing adults (total n = 90) responded to lexical characteristics of 480 English words in a go/no-go lexical decision task. Results from mixed effect regression models showed (a) visual complexity produced small effects in opposing directions for deaf and hearing readers, (b) similar frequency effects, but shifted earlier for deaf readers, (c) more pronounced effects of orthographic neighbourhood density for hearing readers, and (d) more pronounced effects of concreteness for deaf readers. We suggest hearing readers have visual word representations that are more integrated with phonological representations, leading to larger lexically-mediated effects of neighbourhood density. Conversely, deaf readers weight other sources of information more heavily, leading to larger semantically-mediated effects and altered responses to low-level visual variables.

Discourse fluency modulates spoken word recognition in monolingual and L2 speakers

AbstractWe investigated whether fluent language production is associated with greater skill in resolving lexical competition during spoken word recognition and ignoring irrelevant information in non-linguistic tasks. Native English monolinguals and native English L2 learners, who varied on measures of discourse/verbal fluency and cognitive control, identified spoken English words from dense (e.g., BAG) and sparse (e.g., BALL) phonological neighborhoods in moderate noise. Participants were slower in recognizing spoken words from denser neighborhoods. The inhibitory effect of phonological neighborhood density was smaller for English monolinguals and L2 learners with higher speech production fluency, but was unrelated to cognitive control as indexed by performance on the Simon task. Converging evidence from within-language effects in monolinguals and cross-language effects in L2 learners suggests that fluent language production involves a competitive selection process that may not engage all domain-general control mechanisms. Results suggest that language experience may capture individual variation in lexical competition resolution.

Eye Movement Measures of Within-Language and Cross-Language Activation During Reading in Monolingual and Bilingual Children and Adults: A Focus on Neighborhood Density Effects.

We used eye movement measures of first-language (L1) and second-language (L2) paragraph reading to investigate how the activation of multiple lexical candidates, both within and across languages, influences visual word recognition in four different age and language groups: (1) monolingual children; (2) monolingual young adults; (3) bilingual children; and (4) bilingual young adults. More specifically, we focused on within-language and cross-language orthographic neighborhood density effects, while controlling for the potentially confounding effects of orthographic neighborhood frequency. We found facilitatory within-language orthographic neighborhood density effects (i.e., words were easier to process when they had many vs. few orthographic neighbors, evidenced by shorter fixation durations) across the L1 and L2, with larger effects in children vs. adults (especially the bilingual ones) during L1 reading. Similarly, we found facilitatory cross-language neighborhood density effects across the L1 and L2, with no modulatory influence of age or language group. Taken together, our findings suggest that word recognition benefits from the simultaneous activation of visually similar word forms during naturalistic reading, with some evidence of larger effects in children and particularly those whose words may have differentially lower baseline activation levels and/or weaker links between word-related information due to divided language exposure: bilinguals.

Not just form, not just meaning: Words with consistent form-meaning mappings are learned earlier.

By leveraging Phonology-to-Semantics Consistency (PSC), which quantifies form-meaning systematicity as the semantic similarity between a target word and its phonological nearest neighbours, we document a unique effect of systematicity on Age of Acquisition (AoA). This effect is also found after controlling for the effect of neighbourhood density measured for word forms and lexical semantics and several other standard predictors of AoA. Moreover, we show that the effect of systematicity is not reducible to iconicity. Finally, we extensively probe the reliability of this finding by testing different statistical models, analysing systematicity in phonology and orthography and implementing random baselines, reporting a robust, unique negative effect of systematicity on AoA, such that more systematic words tend to be learned earlier. We discuss the findings in the light of studies on non-arbitrary form-meaning mappings and their role in language learning, focusing on the analogical process at the interface of form and meaning upon which PSC is based and how it could help children infer the semantics of novel words when context is scarce or uninformative, ultimately speeding up word learning.

Effects of word frequency and phonological neighborhood density on speech recognition in background noise and competing speech

Clinical speech-in-noise tests typically use materials without contextual constraint or balanced for linguistic properties like word/phoneme frequency. However, real-world linguistic context effects can be substantial and vary by listener and scenario. Here, 38 participants completed the Theo-Victor-Michael (TVM) speech test in four types of background: speech shaped noise (SSN), speech-envelope modulated noise (envSSN), one competing talker (1T), and two competing talkers (2T) (Helfer and Freyman, 2009). The TVM is a matrix test using keywords from a corpus of one- and two- syllable nouns that vary considerably in word frequency (FREQ) and phonological neighborhood density (DENS). Bayesian logistic regression was used to estimate the effects of FREQ/DENS on TVM performance. A multinomial model was used for 1T/2T to assess reporting of target and distractor keywords. Overall, percent-correct recognition increased with increasing keyword FREQ and decreased with increasing keyword DENS. Effects were larger in SSN/envSSN than 1T/2T. Statistically significant but small effects of FREQ/DENS were observed on distractor responses in 1T/2T. Adjusting performance for FREQ/DENS substantially shifted the distribution of scores but only for SSN/envSSN. Performance in 1T/2T may be dominated by non-linguistic factors, and/or less sensitive to FREQ/DENS due to higher difficulty or linguistic competition from the background talkers. [Work supported by VA RR&D Service.]

Investigating the Effects of Orthography, Neighborhood Density, and Frequency on Single Word Recognition in a Visual Search Task

Investigating the Effects of Orthography, Neighborhood Density, and Frequency on Single Word Recognition in a Visual Search Task

Exploring How Phonotactic Knowledge Can Be Represented in Cognitive Networks

In Linguistics and Psycholinguistics, phonotactics refers to the constraints on individual sounds in a given language that restrict how those sounds can be ordered to form words in that language. Previous empirical work in Psycholinguistics demonstrated that phonotactic knowledge influenced how quickly and accurately listeners retrieved words from that part of memory known as the mental lexicon. In the present study, we used three computer simulations to explore how three different cognitive network architectures could account for the previously observed effects of phonotactics on processing. The results of Simulation 1 showed that some—but not all—effects of phonotactics could be accounted for in a network where nodes represent words and edges connect words that are phonologically related to each other. In Simulation 2, a different network architecture was used to again account for some—but not all—effects of phonotactics and phonological neighborhood density. A bipartite network was used in Simulation 3 to account for many of the previously observed effects of phonotactic knowledge on spoken word recognition. The value of using computer simulations to explore different network architectures is discussed.

Onset Neighborhood Density Slows Lexical Access in High Vocabulary 30-Month Olds.

There is consensus that the adult lexicon exhibits lexical competition. In particular, substantial evidence demonstrates that words with more phonologically similar neighbors are recognized less efficiently than words with fewer neighbors. How and when these effects emerge in the child's lexicon is less clear. In the current paper, we build on previous research by testing whether phonological onset density slows lexical access in a large sample of 100 English-acquiring 30-month-olds. The children participated in a visual world looking-while-listening task, in which their attention was directed to one of two objects on a computer screen while their eye movements were recorded. We found moderate evidence of inhibitory effects of onset neighborhood density on lexical access and clear evidence for an interaction between onset neighborhood density and vocabulary, with larger effects of onset neighborhood density for children with larger vocabularies. Results suggest the lexicons of 30-month-olds exhibit lexical-level competition, with competition increasing with vocabulary size.

The signed mental lexicon: Effects of phonological neighborhood density, iconicity, and childhood language experience

Most of what is known about the mental lexicon comes from studies of spoken language and their written forms. Signs differ from spoken/written words in two important ways that may affect lexical recognition: their phonological composition is unique (e.g., more simultaneous than serial structure; few minimal pairs) and many signs are iconic. Using an unprimed lexical decision task in American Sign Language (ASL) and the first available estimates of phonological neighborhood density for any sign language, we found that phonological neighborhood density had an inhibitory effect on latency among low frequency signs. This is the first clear evidence that phonological neighbors spontaneously compete during sign recognition. Iconicity negatively affected accuracy but not reaction times, suggesting that iconicity plays a role in task-related decision processes but not lexical retrieval. Many deaf signers have delayed first language acquisition, and we found that language deprivation had lasting, negative effects on phonological processing and sign recognition speed and accuracy. This work indicates that the lexicons of both spoken and signed languages are organized by form, that lexical recognition occurs through form-based competition (most evident for low frequency items), and that form-meaning mappings do not drive lexical access even when iconicity is pervasive in the lexicon.