Left ear dichotic listening performance on consonant-vowel combinations and digits in subtypes of reading-disabled children

Twenty reading comprehension-disabled (CD) and 20 reading comprehension and word recognition-disabled (CWRD), right-handed male children were matched with 20 normal-achieving age-matched controls and 20 normal-achieving reading level-matched controls and tested for left ear report on dichotic listening tasks using digits and consonant-vowel combinations (CVs). Left ear report for CVs and digits did not correlate for any of the groups. Both reading-disabled groups showed lower left ear report on digits. On CVs the CD group showed a high left ear report but only when there were no priming precursors, such as directions to attend right first and to process digits first. Priming effects interfered with the processing of both digits and CVs. Theoretically, the CWRD group seems to be characterized by a depressed right hemisphere, whereas the CD group may have a more labile right hemisphere, perhaps tending to overengagement for CV tasks but vulnerable to situational precursors in the form of priming effects. Implications extend to (1) subtyping practices in research with the learning-disabled, (2) inferences drawn from studies using different dichotic stimuli, and (3) the neuropsychology of reading disorders.     

Dichotic listening and sleep deprivation: vigilance effects

Twelve sleep-deprived and 13 non-deprived Navy cadets were tested with the dichotic listening procedure for effects of sleep deprivation on hemispheric asymmetry and sustained attention. Consonant-vowel syllables were presented to the subjects in three different conditions, a divided (non-forced) attention condition, a forced right ear and a forced left ear attention condition. In the two forced attention conditions the subjects were instructed to focus attention only on the right or left ear stimulus. The results showed an expected right ear advantage for both groups during the non-forced and forced right attention conditions, indicating superior left hemisphere processing. During the forced left attention condition, the sleep-deprived subjects showed no ear advantage at all, while the non-deprived subjects showed an expected left ear advantage. The results are discussed within a theoretical framework of a dual process model, where sleep deprivation disrupts the ability to sustain attention, caused by a temporary failure of the right hemisphere's top-down (instruction-driven) processing to override the left hemisphere's bottom-up (stimulus-driven) processing.     

Central auditory processing. V. Ear advantages for acoustic stimuli in baboons

Four baboons (Papio cynocephalus) were tested using food as reward for ear advantages in the monaural discrimination of pure tones, three-tone musical chords, synthetically constructed consonant-vowels, and vowels. All four animals showed highly significant and reproducible ear advantages for each class of acoustic stimulus with marked individual differences in the direction of their ear asymmetry. The results obtained in these experiments represent the first evidence of ear asymmetries for different classes of acoustic stimuli in a nonhuman species. Further, the ear advantages found in these animals under monaural conditions resemble those obtained with dichotic presentation in human subjects and thus suggest that the baboon may be a valuable model of central auditory processing of various types of acoustic stimuli in man.     

The Phonetic Integration of Speech and Non-speech Sounds: Effects of Perceived Location

The third-formant (F3) transition of a three-formant /da/ or /ga/ syllable was extracted and replaced by sine-wave transitions that followed the F3 centre frequency. The syllable without the F3 transition (base) was always presented at the left ear, and a /da/ (falling) or /ga/ (rising) sine-wave transition could be presented at either the left, the right, or both ears. The listeners perceived the base as a syllable, and the sine-wave transition as a non-speech whistle, which was lateralized near the left ear, the right ear, or the middle of the head, respectively. In Experiment 1, the sine-wave transition strongly influenced the identity of the syllable only when it was lateralized at the same ear as the base (left ear). Phonetic integration between the base and the transitions became weak, but was not completely eliminated, when the latter was perceived near the middle of the head or at the opposite ear as the base (right ear). The second experiment replicated these findings by using duplex stimuli in which the level of the sine-wave transitions was such that the subjects could not reliably tell whether a /da/ or a /ga/ transition was present at the same ear as the base. This condition was introduced in order to control for the possibility that the subjects could have identified the syallables by associating a rising or falling transition presented at the left ear with a /da/ or /ga/ percept. Alternative suggestions about the relation between speech and non-speech perceptual processes are discussed on the basis of these results.     

Ear asymmetry in a dichotic detection task

Pairs of consonant-vowel (CV) syllables were presented dichotically to Ss who were instructed to monitor for the presence of a target CV which could occur in either ear. Ss responded by depressing a response button ; reaction time (RT) was also recorded. Right ear targets were detected 6.2% more frequently, on the average, than left ear targets and had an average RT 50 msec quicker than their left ear counterparts. These results demonstrate the existence of a right ear superiority in dichotic listening when a nonverbal motor response measure is used, supporting the contention that the ear asymmetry phenomenon is truly perceptual in nature and not merely due to the lateralization of verbal output. Two alternative explanations of the RT difference between left and right ear targets are offered. One attributes this difference to the time necessary for intercortical transfer of right hemisphere information, while the second holds that it is due to the longer times needed by the right hemisphere to process information projected to it.     

Attentional set in pure- versus mixed-lists in a dichotic listening paradigm

An experiment was designed to assess the contribution of attentional set to performance on a forced choice recognition task in dichotic listening. Subjects were randomly assigned to one of three conditions: speech sounds composed of stop consonants, emotional nonspeech sounds, or a random combination of both. In the groups exposed to a single class of stimuli (pure-list), a REA (right ear advantage) emerged for the speech sounds, and a LE (left ear advantage) for the nonspeech sounds. Under mixed conditions using both classes of stimuli, no significant ear advantage was apparent, either globally or individually for the speech and nonspeech sounds. However, performance was more accurate for the left ear on nonspeech sounds and for the right ear for speech sounds, regardless of pure versus mixed placement. The results suggest that under divided attention conditions, attentional set influences the direction of the laterality effect.     

Attention and perception: An information-integration perspective

Attentional effects in perceptual processing are analyzed within a framework of a fuzzy logical model of perception. The recognition of a pattern is conceptualized as involving three stages of processing: featural evaluation, integration of features, and pattern classification. The model predicts no loss of resolution when multiple sources of information are integrated to recognize a perceptual event. This model is contrasted with a single-channel model in which only one source of information can be recognized at a time. The task involves a relatively novel situation of speech perception by ear and eye. No attentional decrement is observed when observers process both auditory and visual speech specifying a single speech event. This result contrasts with previous studies showing a loss when attention has to be divided between different events along auditory and visual modalities. The different results are interpreted in terms of the number of events that have to be processed. Processing two different modalities leads to an attentional decrement when the two inputs specify different events whereas no attentional decrement occurs when these inputs are integrated to recognize a single event. A distinction is made between detection that requires only the evaluation of a single source of information and recognition that requires the evaluation and integration of multiple sources of information. The current framework is also used to discuss previous empirical and theoretical work and the issue of early versus late selection.     

Ear of input as a determinant of pitch-memory interference

Six experiments to evaluate the effect of presentation ear on pitch-memory interference were conducted using undergraduates as listeners. The task was to compare the pitch of two tones that were separated by an interval that included eight interpolated tones; the interpolated tones were presented either ipsilaterally or contralaterally to the presentation ear of the comparison tones. When the ear of interpolated-tone presentations was blocked, and therefore predictable, ipsilateral interference was greater than contralateral. In contrast, when the interpolated-tone presentation ear was varied randomly from trial to trial, ipsilateral and contralateral interferences were equivalent. These results are analogous to results found in previously reported auditory backward recognition masking (ABRM) experiments and suggest that the ABRM effect may be due, in part, to pitch-memory interference. Implications for theories of auditory processing and memory are discussed.     

Backward masking and asymmetry of processing for vowels differing in acoustical similarity

Several investigations have reported problems in demonstrating for vowels the phenomena of backward masking and right ear advantage so easily demonstrated for consonants. An experiment is reported on the dichotic backward masking (BM) of acoustically similar and dissimilar sets of vowels in consonant-vowel syllables. The results suggest that increasing perceptual difficulty by varying the acoustic similarity of the stimulus set augments BM. A second experiment showed that the right ear advantage (REA) was augmented by manipulating the acoustic similarity of the stimulus set and by decreasing intelligibility through the addition of noise. This and other evidence was employed to ascribe variations in both REA and BM to the interaction of perceptual processing time with information decay in precategorical acoustical storage. It is argued that this process interaction underlies statistical interactions in dichotic data which show that variations in difficulty (discriminability, noise addition, brain deterioration) affect most adversely the least favoured items (those presented earlier, those on the unattended ear, those on the left ear).     

Attentional strategies in dichotic listening

A person can attend to a message in one ear while seemingly ignoring a simultaneously presented verbal message in the other ear. There is considerable controversy over the extent to which the unattended message is actually processed. This issue was investigated by presenting dichotic messages to which the listeners responded by buttonpressing (not shadowing) to color words occurring in the primary ear message while attempting to detect a target word in either the primary ear or secondary ear message. Less than 40% of the target words were detected in the secondary ear message, whereas for the primary ear message (and also for either ear in a control experiment), target detection was approximately 80%. Furthermore, there was a significant negative correlation between buttonpressing performance and secondary ear target-detection performance. The results were interpreted as being inconsistent with automatic processing theories of attention.     

3-5岁儿童对物体认知及对他人认知过程的研究

本文探讨了3-5岁儿童对物体的认知及对他人的认知过程.结果表明儿童通过视觉认知外界物体时,物体的外观特性(形状与颜色)起着主要的作用;在认知过程中,通过触觉及视觉对物体认知的信息产生矛盾时,儿童对物体的真实性往往产生怀疑及犹疑不决,影响对物体的真实性认知.儿童对他人认知行为认知的发展水平,取决于儿童对物体认知结构的复杂性.3-5岁儿童对物体认知能力随年龄的增长而提高.     

The investigation of ear asymmetry by simple and disjunctive reaction-time tasks

In a disjunctive reaction-time task in which Ss responded to clicks presented to one ear while white noise was presented to the other, RT was significantly faster to stimuli presented to the left ear than to the right ear. In a simple reaction-time task, using the same stimuli. there was no difference in R T to stimuli presented to right or left ear. The results were discussed in relation to functional asymmetry of the cerebral hemispheres. and were taken to support a perceptual interpretation of the ear asymmetry effect.     

The repressor personality and avoidant information processing: A dichotic listening study

The present research was designed to investigate the proposition that repressors, operationally defined by the conjunction of low anxiety and high defensiveness, are particularly adept at avoiding the processing of information when motivated to do so. Four groups of participants (nondefensive-low anxious, high anxious, repressors, and defensive-high anxious) were administered a dichotic listening task involving neutral or negative affective words presented in the unattended ear. Participants shadowed the material presented to the attended ear and simultaneously responded to a probe task presented on a video monitor. Results revealed that repressors made significantly fewer shadowing errors than high anxious and defensive-high anxious participants and marginally significantly fewer shadowing errors than low anxious participants for both neutral and negative words. High anxious participants, however, were later able to recognize the negative words that had been presented to the unattended ear at well above chance levels, whereas the recognition memory of repressors for such negative unattended words was at chance levels. In addition, repressors' responses to a postexperiment questionnaire indicated a significantly greater number of distracting thoughts during the experiment relative to other participants. Repressors, it seems, are indeed skillful at avoidant information processing and this capacity may well be related to the emotional memory deficits they have displayed in previous research.     

Schizotypy and hemisphere function—IV : Story comprehension under binaural and monaural listening conditions

An experiment is reported examining the story-comprehension performance of normal Ss under left ear, right ear and binaural listening conditions, the results being related to scores on the schizotypy (STA) scale of a previously described questionnaire (STQ). Hypotheses were derived from the observations of other investigators that schizophrenics and the children of schizophrenics show impaired binaural relative to monaural and poor left ear performance on the task; a pilot study had indicated that this might also be the case in normal high STA scorers. Results of the main experiment failed to confirm predictions, though in male Ss several significant effects were observed. High schizotypals showed weakened asymmetry, reflected in better left ear relative to right ear performance, compared with low schizotypals; they also showed a smaller binaural/left ear difference. Some reasons for the discrepancy between these and previous findings using a similar task are considered and the results are discussed in relation to other studies of schizotypy and hemisphere function carried out in our laboratory.     

The intermodal representation of speech in newborns

It has been proposed that speech is specified by the eye, the ear, and even the skin. Kuhl and Meltzoff (1984) showed that 4-month-olds could lip-read to an extent. Given the age of the infants, it was not clear whether this was a learned skill or a by-product of the primary auditory process. This paper presents evidence that neonate infants (less than 33 h) show virtually identical patterns of intermodal interaction as do 4-month-olds. Since they are neonates, it is unlikely that learning was involved. The results indicate that human speech is specified by both eye and ear at an age when built-in structural sensitivities provide the most plausible explanation.     

自我面孔识别的神经机制：基于fMRI研究的ALE元分析

自我面孔识别反映了个体通过自我与他人的区分识别出自我面孔的过程。本文采用ALE元分析的方法, 对自我面孔识别的fMRI研究进行系统的定量分析, 探究自我面孔识别的神经基础。结果显示, 自我面孔识别的关键脑区包括顶上小叶、额中回、额下回、脑岛、梭状回、楔前叶和枕叶皮层。另外, 自我面孔识别可能包括两个层面的加工过程：知觉层面的加工整合过程以及由知觉引发的评价和情绪反应过程。知觉加工整合涵盖了自我面孔识别的各个加工阶段, 主要涉及枕叶、梭状回和楔前叶的功能; 而评价加工及情绪反应过程则发生在自我面孔识别的中晚期, 主要涉及顶上小叶、额中回、额下回及脑岛的功能。未来研究可结合时间和空间数据并关注脑区间的协同功能, 考察与内感受的神经关联, 开展临床研究并探索威胁信息的影响机制。     

Early Effect of Phonological Information in Korean Visual Word Recognition: An ERP Investigation with Transposed Letters

The purpose of this study was to examine the role of phonological information on visual word recognition by using letter transposition effects. The Korean writing system gives a unique opportunity to investigate such phenomenon since the transposition of the beginning consonant (onset) and the end consonant (coda) of a certain syllable allows one to keep the coda phonology constant while changing the written alphabetic characters. In this study, 23 participants’ ERPs to such transposition cases were compared with the ERPs to cases that do not maintain coda phonology while the participants were performing a go/no-go lexical decision task for visually presented letter strings. The results of the current study showed that transposed materials with original phonological information produce less N250 than both the baseline condition and the transposed materials with different phonological information condition. The results suggest that phonological information is used early in the lexical process in Korean and early orthographic processing is influenced by the characteristics of the grapheme to phoneme conversion process.     

Auditory lateralization for speech in language-impaired children.

The ability of five language-impaired (LI) children and five matched controls, aged 7-10 years, to discriminate natural pairs of consonant-vowel syllables contrasted on place of articulation and voicing, presented to the right or left ear with white noise in the contralateral ear, was investigated. The general pattern of errors indicated that LI children had more difficulty than controls in discriminating place of articulation contrasts only when they were presented to the left ear, as well as a difficulty in discriminating voice contrasts selective to the right ear. The results are discussed in terms of acoustic integration and suggest that bihemispheric dysfunction is a basis for specific language impairment.     

Neighborhood frequency effects in visual word recognition: a comparison of lexical decision and masked identification latencies

Recent research suggests that the time to recognize a visually presented word may be a function of the frequencies of orthographically similar words. More precisely, recognition latencies and errors appear to increase significantly as soon as the stimulus word is orthographically similar to at least one other higher frequency word. This phenomenon, referred to as the neighborhood frequency effect, was subjected to further experimental testing, using a larger selection of words of varying frequency and length, and using a new experimental technique that proved to be extremely sensitive to such effects. The results provide additional support for earlier observations of neighborhood frequency effects. It is also demonstrated that clear word-frequency effects do obtain when neighborhood frequency is held constant. The results support activation-based accounts of the word-recognition process.     

Stimulus intensity, attentional instructions, and the ear advantage during dichotic listening

The present experiment was designed to investigate the effects of the following two variables on the identification of dichotically presented CV syllables: (1) the relative difference in intensity levels of the stimuli presented to the two ears and (2) the instructions to attend to both ears or to focus attention on one ear. As expected for a verbal task, more CV's were identified from the right ear than from the left ear. Furthermore, identification of stimuli presented to one ear improved when (1) those stimuli were relatively higher in volume than the stimuli presented to the other ear and (2) when subjects were instructed to focus attention on only that ear rather than distribute attention across both ears. Of particular importance is the finding that the effects of relative stimulus intensity are the same under conditions of focused attention as under conditions of divided attention. This finding is inconsistent with an attention explantation of the relative intensity effects. Instead, the results are consistent with a model of dichotic listening in which ear of stimulus presentation and relative stimulus intensity influence a perceptual stage of information processing and attentional instructions influence a subsequent response selection stage.