Neighborhood Of Frequency Research Articles

Noise-induced hearing loss in young adults: the role of personal listening devices and other sources of leisure noise.

No consensus exists regarding the magnitude of the risk of noise-induced hearing loss (NIHL) associated with leisure noise, in particular, personal listening devices in young adults. Examine the magnitude of hearing loss associated with personal listening devices and other sources of leisure noise in causing NIHL in young adults. Prospective auditory testing of college student volunteers with retrospective history exposure to home stereos, personal listening devices, firearms, and other sources of recreational noise. Subjects underwent audiologic examination consisting of estimation of pure-tone thresholds, speech reception thresholds, and word recognition at 45 dB HL. Fifty subjects aged 18 to 30 years were tested. All hearing thresholds of all subjects (save one-a unilateral 30 dB HL threshold at 6 kHz) were normal, (i.e., 25 dB HL or better). A 10 dB threshold elevation (notch) in either ear at 3 to 6 kHz as compared with neighboring frequencies was noted in 11 (22%) subjects and an unequivocal notch (15 dB or greater) in either ear was noted in 14 (28%) of subjects. The presence or absence of any notch (small or large) did not correlate with any single or cumulative source of noise exposure. No difference in pure-tone threshold, speech reception threshold, or speech discrimination was found among subjects when segregated by noise exposure level. The majority of young users of personal listening devices are at low risk for substantive NIHL. Interpretation of the significance of these findings in relation to noise exposure must be made with caution. NIHL is an additive process and even subtle deficits may contribute to unequivocal hearing loss with continued exposure. The low prevalence of measurable deficits in this study group may not exclude more substantive deficits in other populations with greater exposures. Continued education of young people about the risk to hearing from recreational noise exposure is warranted.

Clustering and phase resetting in a chain of bistable nonisochronous oscillators

We consider a chain with many locally coupled bistable nonisochronous oscillators. We show that on the background of a disordered amplitude distribution either phase or frequency clusters form in the chain. Cluster location varies according to the amplitude distribution. In the case of frequency clusters their interaction leads to phase resetting in an isolated oscillator located between two neighboring frequency clusters.

Global dinucleotide signatures and analysis of genomic heterogeneity

Early biochemical experiments measuring nearest neighbor frequencies established that the set of dinucleotide relative abundance values (dinucleotide biases) is a remarkably stable property of the DNA of an organism. Analyses of currently available genomic sequence data have extended these earlier results, showing that the dinucleotide biases evaluated for successive 50 kb segments of a genome are significantly more similar to each other than to those of sequences from more distant organisms. From this perspective, the set of dinucleotide biases constitutes a ‘genomic signature’ that can discriminate sequences from different organisms. The dinucleotide biases appear to reflect species-specific properties of DNA stacking energies, modification, replication, and repair mechanisms. The genomic signature is useful for detecting pathogenicity islands in bacterial genomes.

The effects of neighborhood frequency in reading and lexical decision.

To test the effect of the frequency of orthographic "neighbors" on the identification of a printed word, two sets of words were constructed (equated on the number of neighbors, word frequency, and number of letters); in one set, the words had no higher frequency neighbors and in the other set, they had at least one higher frequency neighbor. Identification was slower for the latter set. In Experiment 1, this was indexed by longer response times in a lexical decision task. In Experiment 2, the target words were embedded in sentences, and slower identification was indexed by disruptions in reading: more regressions back to the words with higher frequency neighbors and longer fixations on the text immediately following these words. The latter results indicate that a higher frequency neighbor affects relatively late stages of lexical access, an interpretation consistent with both activation-verification and interactive activation models.

Effects of syllable frequency and syllable neighborhood frequency in visual word recognition.

Effects of syllable frequency and syllable neighborhood frequency in visual word recognition.

The effects of neighborhood frequency in reading and lexical decision.

The effects of neighborhood frequency in reading and lexical decision.

Effects of syllable frequency and syllable neighborhood frequency in visual word recognition.

Three experiments were carried out to analyze the role of syllable frequency in lexical decision and naming. The results show inhibitory effects of syllable frequency in the lexical decision task for both high- and low-frequency words. In contrast, the effect of syllable frequency is facilitatory in the naming task. A post hoc analysis revealed the important role played by the number of higher frequency syllabic neighbors (words that share a syllable with the target) in the lexical decision task and the role of the frequency of the first syllable in the naming task. Experiment 3 manipulated the neighborhood syllable frequency directly by comparing words with few higher frequency syllabic neighbors and words with many higher frequency syllabic neighbors in the lexical decision task; an inhibitory neighborhood syllable frequency effect was found. The results are interpreted in terms of current models of visual word recognition and word naming.

The neighborhood characteristics of malapropisms.

This study examined the phonological neighborhood characteristics (frequency, density, and neighborhood frequency) of 138 malapropisms. Malapropisms are whole word substitutions that are phonologically, but not semantically, related. A statistical analysis of a speech error corpus suggests that neighborhood density and word frequency differentially affected the number of malapropisms. Specifically, a greater number of malapropisms were found among high frequency words with dense neighborhoods than with sparse neighborhoods. Exactly the opposite pattern was found among low frequency words. That is, more errors were found among low frequency words with sparse neighborhoods than with dense neighborhoods. More malapropisms resided in low frequency neighborhoods than in high. The average word frequency, average neighborhood density, and average neighborhood frequency of the malapropisms were significantly lower than the same averages computed from randomly sampled control words. Finally, more target words were replaced by error words that had relatively higher frequency than by error words that had relatively lower frequency. The implications of these findings for models of lexical representation and processing are discussed.

Auditory filters measured at neighboring center frequencies.

Auditory filters were derived in 20 normal-hearing human listeners at center frequencies (CFs) of 913, 1095, 3651, and 4382 Hz using the roex (p,r) method. Comparisons were made between slopes of the filters' skirts at the neighboring CFs with filter output levels of 45 and 70 dB. The same comparisons were made with regard to filter equivalent rectangular bandwidth (ERB). In the 1000-Hz region, the low-frequency slopes (Pl) of filters centered at 913 and 1095 Hz were significantly correlated at both stimulus levels, while the high-frequency slopes (Pu) were similar only at the high test level. In the 4000-Hz region, for sinusoids of 3651 and 4382 Hz, the level effect was clearer as both Pu and Pl values diverged at the low level but were related at high levels. The ERBs centered at the same CFs displayed a similar level dependence. At the stimulus level most likely to be affected by an active feedback mechanism, auditory filters centered at nearly the same frequency displayed quite distinct frequency selectivity, and this trend was stronger in the 4000-Hz region than the 1000-Hz region. The findings suggest that a saturating, active cochlear mechanism may not be distributed evenly, or contribute to peripheral tuning with equal effectiveness throughout the length of the partition.

Positional neighborhood effects on spoken word recognition

Previous work has shown that the composition of similarity neighborhoods has demonstrable effects on spoken word recognition. In a reanalysis of previously collected data of word identification and lexical decision, the effects of similarity neighborhoods on spoken word recognition were further explored by asking two specific questions. (1) Do neighbors at each phoneme position within a spoken word have equivalent effects on word recognition? (2) Is average neighborhood frequency or the highest neighborhood frequency the superior predictor of recognition performance? Our results show that the number of neighbors defined on the basis of initial phoneme substitution affects word recognition more than the neighbors at other phoneme positions. And, it is found that the word with the maximum frequency in a neighborhood is as good a predictor of recognition performance as the average neighborhood frequency. The implications of these findings for theories of spoken word recognition will be discussed.

Spoken word recognition in older adults: Activation and decision

Spoken word recognition may be characterized by two successive stages: (1) activation of multiple form-based representations in memory and (2) frequency-biased perceptual decision. Recent research has suggested that older adults show deficits in controlled processing in perceptual and memory tasks, suggesting that while activation mechanisms subserving spoken word recognition may remain relatively intact over time, perceptual decision processes degrade. In order to investigate the possible loci of older adults’ recognition difficulties, perception of specially selected words that orthogonally varied on three dimensions was examined: word frequency, neighborhood density, and neighborhood frequency. Effects of neighborhood density are typically associated with activation mechanisms, whereas neighborhood frequency is associated with perceptual decision. The implications of these results for theories of aging and spoken word recognition will be discussed. [Work supported by grants from NIDCD.]

‘‘SLIP-ing’’ in phonologically similar neighborhoods

Phonological speech errors are the class of speech errors in which one or more phonemes are added, deleted, substituted, or reversed. Previous work [Dell (1990); Stemberger and MacWhinney (1986)] has found that low-frequency words are more likely to be involved in phonological speech errors than high-frequency ones. If word frequency, influences performance in speech production, do other characteristics of words, such as neighborhood density or neighborhood frequency, influence speech production? The influence of phonologically similar neighborhoods on a type of whole word speech error (malapropisms) has previously been demonstrated [Vitevitch (1996)]. The present research examined the influence of phonologically similar neighborhoods on phonological speech errors. Using the SLIPS technique [Motley and Baars (1976)], phonological speech errors were elicited from participants with real word pairs that varied in their neighborhood characteristics. The results show that low-frequency words ‘‘slipped’’ more often than high-frequency ones, replicating past results from error corpora and from other studies using this methodology. Moreover, words with sparse phonologically similar neighborhoods tended to ‘‘slip’’ more than words with dense phonologically similar neighborhoods. The implications for these findings on models of speech production, speech perception, and lexical representation are discussed.

Effects of masked repetition priming and orthographic neighborhood in visual recognition of words.

The role of orthographic neighborhood (neighborhood size and neighborhood frequency) in visual-word recognition was analyzed using the masked repetition-priming paradigm. Specifically, we varied stimulus-onset asynchrony (33, 50, and 67 msec.) and type of prime (identical, unrelated, unprimed) in a lexical decision task. Analyses show additive effects of repetition and stimulus-onset asynchrony. Further, the unrelated condition overestimated the repetition effects relative to an unprimed condition. Facilitatory effects of neighborhood size and inhibitory effects of neighborhood frequency were also found. The results are interpreted in terms of current models of visual-word recognition.

Orthographic neighborhood structure and lexical access

An experiment addressed whether lexical decision response latency and error rate are influenced by orthographic neighborhood structure. It was found that words with several higher-frequency neighbors were responded to more slowly and less accurately than words with fewer higher-frequency neighbors, even though the stimulus words were matched oh number of neighbors, word frequency, neighborhood frequency, number of higher-frequency neighbors, word length, and number of syllables. The results indicate that frequency is a relative effect dependent on the structure of the neighborhood. A word at the “bottom” of its neighborhood will be affected by the lexical representations of its higher-frequency neighbors. However, a word at the “top” of its neighborhood does not appear to be affected by the lexical representations of its neighbors.

Building lexical neighborhoods.

The Neighborhood Activation Model (NAM) states that the speed and accuracy of spoken word recognition are a function of the number and nature of neighbors—or similar sounding words—activated in memory by stimulus input. In particular, the model states that spoken word recognition is a function of (1) target word frequency, (2) similarity neighborhood density, and (3) similarity neighborhood frequency. In a pretest–training –posttest design, these three factors were manipulated using nonword target words and nonword neighbors to test directly predictions of NAM. The results were only partially consistent with the model. As predicted, processing times to high‐frequency targets increased as a function of neighborhood density. However, processing times for low‐frequency targets actually decreased with increased neighborhood density. Furthermore, no significant effects of neighborhood frequency were obtained. The implications of these findings for NAM and other models of spoken word recognition are discussed.

The neighborhood characteristics of malapropisms.

This study examined the neighborhood characteristics (frequency, density, and neighborhood frequency) of 138 malapropisms (whole word errors). A qualitative analysis suggests that words that are more often involved in malapropisms have low neighborhood frequencies. Additionally, these words tend to be either high‐frequency target words in dense neighborhoods, or low‐frequency target words in sparse neighborhoods. Finally, malapropisms tended to occur such that the word that was substituted for the intended word was more frequent than the intended word. The implications of these findings for models of lexical representation and processing are discussed.

Closed-set response formats: An evaluation within the framework of the neighborhood activation model

It has been suggested that open- and closed-set response formats engage distinct perceptual mechanisms during spoken word recognition. One finding consistent with this hypothesis is that lexical difficulty (neighborhood density and neighborhood frequency) reduce identification performance in open- but not closed-set formats [Kirk etal., Ann. Otol. Rhinol. Laryngol. (in press)]. An alternative explanation for the differential effects of response format on lexical difficulty in this earlier study, however, is that the response alternatives were not systematically selected to maximize confusability with the target items. Therefore, the present investigation compared the effects of lexical difficulty in open- and closed-set response formats when the response alternatives in the closed-set condition were the five words most confusable with the target item. Preliminary results indicate that, relative to the open-set condition, when the difficulty of alternatives is controlled, identification within the closed-set format is improved for hard, but not for easy, words. It is hypothesized that the improved word recognition for hard words in closed-set formats is the result of reducing the viable candidate set. In contrast, the already small candidate set of easy words minimizes the benefits of reducing the number of viable candidate items.

Neighborhood size and neighborhood frequency effects in word recognition.

What are the effects of a word's orthographic on the word recognition process? Andrews (1989) reported that large neighborhoods facilitate lexical access (the size Grainger, O'Regan, Jacobs, & Segui (1989) reported that higher frequency neighbors inhibit lexical access (the neighborhood frequency effect). Because size and frequency typically covary (words with large neighborhoods will usually possess higher frequency neighbors), these findings would seem to contradict one another. In the present study, 6 experiments on the effects of size and frequency indicated that, at least for low-frequency words, large neighborhoods do facilitate processing. However, the existence of higher frequency neighbors seems to facilitate rather than inhibit processing. The implications of these findings for serial and parallel models of lexical access are discussed. Much of the research on visual word recognition has focused on the issue of lexical access. Consequently, a number of models of the lexical access process have been proposed, each providing a slightly different account of the various factors that affect this process. Consider, for example, the factor that is probably the most studied in this literature—printed-word frequency. The standard finding is that high-frequency words are processed faster than lowfrequency words. In Forster's (1976) serial search model, this effect is explained in terms of a serial-search process. According to the model, the entries in the lexicon are organized according to word frequency. The search for a match between the sensory input and the correct lexical entry proceeds in a serial manner, starting with the closest matching higher frequency entries. Thus, high-frequency words are identified more quickly than low-frequency words by virtue of their order in the search set. Alternatively, in activation-b ased models, such as McClelland and Rumelhart's (1981) interactive-activation model, frequency effects are attributed to the higher resting activation

Neighborhood size and neighborhood frequency effects in word recognition.

Neighborhood size and neighborhood frequency effects in word recognition.

The jamming avoidance response in Eigenmannia is controlled by two separate motor pathways

The gymnotiform fish Eigenmannia generates weakly electric signals for electrolocation and communication. The signals are produced by electric organ discharges (EODs) that are driven by a medullary pacemaker nucleus. To avoid jamming by neighboring conspecifics with similar frequencies, a fish raises its own EOD frequency if the neighbor's frequency is lower, and it lowers its EOD frequency if the neighbor's frequency is higher (Watanabe and Takeda, 1963). Both the raising and lowering of EOD frequency of this jamming avoidance response (JAR; Bullock et al., 1972) are thought to be controlled by feature-extracting neurons in the diencephalic prepacemaker nucleus (PPn-G) that discriminate the sign of the frequency difference between the jamming signal and the fish's EOD (Kawasaki et al., 1988a; Rose et al., 1988; for review, see Heiligenberg, 1991). These prepacemaker neurons are excited in response to lower jamming frequencies, thereby raising the frequency, and inhibited by higher jamming frequencies, producing a discharge deceleration. The results of experiments presented here, however, suggest a mechanism for the motor control of the JAR that is different from the one described previously (see, e.g., Heiligenberg, 1991). Two prepacemaker nuclei, one PPn-G and one sublemniscal prepacemaker nucleus (SPPn) (Keller et al., 1991 a,b), which provide the only known inputs to the pacemaker, were lesioned selectively. This article explores the effects of these lesions on the JAR. Pharmacological experiments were used to elucidate the transmitter types involved. The results suggest that the JAR is controlled by two separate motor pathways. One controls frequency rises and originates in the dorsal substructure of the nucleus electrosensorius (Keller, 1988). It sends excitatory connections to the diencephalic prepacemaker and finally to the pacemaker nucleus, where AMPA-type receptors mediate the synaptic transmission. The second pathway controls frequency decreases and originates in the ventral substructure of the nucleus electrosensorius. It provides GABAergic input to the SPPn. The SPPn is tonically active and also controls the EOD frequency even in the absence of jamming signals. Its projection to the pacemaker nucleus is mediated by NMDA-type receptors. The results of this study suggest that there is no single population of final, feature-extracting elements or "recognition units" that controls JAR-related shifts of the pacemaker frequency. Instead, the motor control of the JAR consists of an interaction of two independent pathways according to a "push-pull" principle.