Performance of paranoid schizophrenics on a dichotic listening task.

Used 15 adult normals and 15 institutionalized paranoid schizophrenics in a dichotic listening task within a 2 (Groups) * 2 (Associated or Unassociated Word List) * 2 (Presentation Rate) design, with repeated measures on the last 2 variables. Presentation rates were either 1 or 3 sec. Dependent variables were word recall, intrusion errors, and strategy use and accuracy. Normals recalled significantly more information than paranoid schizophrenics under all memory conditions and had significantly fewer total intrusion errors. For both groups, information recall was significantly better under the associative conditions (particularly associative structure, 3-sec presentation rate). Under the varying structure conditions, paranoid schizophrenics did not employ optimal strategies with the same frequency or degree of accuracy as normals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A second testing of paranoid schizophrenics on a dichotic listening task

Data from 15 adult institutionalized Ss tested twice over a 1-yr period show a slight deterioration in organizational abilities for short-term memory task performance over the succeeding times of measurement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of aphasic and non-brain-injured adults on a dichotic CV-syllable listening task

A dichotic CV-syllable listening task was administered to a group of eleven non-brain-injured adults and to a group of eleven adult aphasics. The results of this study may be summarized as follows: 1)The group of non-brain-injured adults showed a slight right ear advantage for dichotically presented CV-syllables. 2)In comparison with the control group the asphasic group showed a bilateral deficit in response to the dichotic CV-syllables, superimposed on a non-significant right ear advantage. 3) The asphasic group demonstrated a great deal of intersubject variability on the dichotic task with six aphasics showing a right ear preference for the stimuli. The non-brain-injured subjects performed more homogeneously on the task. 4) The two subgroups of aphasics, a right ear advantage group and a left ear advantage group, performed significantly different on the dichotic listening task. 5) Single correct data analysis proved valuable by deleting accuracy of report for an examination of trials in which there was true competition for the single left hemispheric speech processor. These results were analyzed in terms of a functional model of auditory processing. In view of this model, the bilateral deficit in dichotic performance of the asphasic group was accounted for by the presence of a lesion within the dominant left hemisphere, where the speech signals from both ears converge for final processing. The right ear advantage shown by one asphasic subgroup was explained by a lesion interfering with the corpus callosal pathways from the left hemisphere; the left ear advantage observed within the other subgroup was explained by a lesion in the area of the auditory processor of the left hemisphere.     

Sensation seeking and selective attention: Focused and divided attention on a dichotic listening task.

Differences in selective attention as a function of sensation seeking, extraversion, neuroticism, and psychoticism were examined in 108 undergraduates using a dichotic listening task. Dependent measures included shadowing performance, reaction time (RT) to a secondary light task, target detection, and recall. Results suggested that high sensation seekers have better focused attentions than low sensation seekers, and these effects were strongest on the 1st trials of the shadowing tasks. Higher sensation seekers did not attend differently than low sensation seekers to words related to their interests (sexual, violent, or drug related). Extraversion was associated with greater recall of these kinds of words, although there were no overall differences in selective attention as a function of Eysenck's dimensions. The role of arousal in personality and attention is discussed, particularly in regard to the response of sensation seekers to task novelty. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lateralization of receptive language in preschoolers: Test–retest reliability in a dichotic listening task.

On 2 occasions dichotic digit tapes were presented to 29 right-handed children (aged 33–65 mo). Results indicate that the dichotic listening tasks yielded measures with sufficient test–retest stability to permit reliable group comparisons, but that such indices may differ in terms of their contamination by sample-specific distributions of ability levels. It is suggested that conclusions not be drawn from such measures unless different indices of laterality show converging results and that when groups are compared, investigators include tabulations of both the difference and accuracy scores in their results. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Baseline asymmetries in brain electrical activity predict dichotic listening performance.

Forty-four right-handed participants were assessed on 2 occasions 6 weeks apart on electrophysiological measures of activation asymmetry derived from spectral estimates of electroencephalogram (EEG) alpha power in homologous scalp electrodes. Approximately 4 months following the final EEG assessment. participants were administered a dichotic listening CV-syllables task. Overall, participants exhibited a highly significant right-ear advantage. Differences among individuals in ear asymmetry were predicted by the earlier recorded electrophysiological data. Participants with greater activation in left-sided posterior temporal and parietal regions showed a larger right-ear advantage. In addition, a larger right-ear advantage was predicted by right-sided prefrontal activation. These data indicate that some of the variance in dichotic listening performance can be explained by dispositional activation asymmetries and is associated with a complex pattern of posterior and anterior activation asymmetries. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of method of recall on performance in the dichotic listening task.

Reports 2 experiments with 100 undergraduates in which Ss were required to recall dichotically presented digits (3/1/2-span) either vocally or in writing. It was found that items in the 1/2-span reported 2nd were recalled significantly more accurately with written as compared with vocal recall. Data suggest that the differential accuracy of recall of the items in the 2 1/2-spans, which is normally reported, is attributable, partially at least, to interference at output produced by the vocalization of items in the 1st 1/2-span. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of handedness, family history and sex on the performance of a dichotic listening task

The action of some drugs on the eye may lead to the occurrence of unforeseen ocular and extraocular reactions. Vincaleukoblastin (Velbe) provokes serious corneal lesions with a healing time of two weeks and a half. The local application of Neo-Synephrine eye drops (10%) and Mydrial-Atropine ointment may lead in the case of a pharmacogenetic disposition to disagreeable systemic effects. In one case of preparation for a cataract operation by akinesis and retrobulbar injection, Novocain was changed by mistake with Pilocarpinum hydrochloricum by the error of a pharmaceutical firm. This led to severe complications, which could by successfully treated with Chlorpromazine (Largactil). The knowledge of these clinical observations may be of greater usefulness in the preventation of untoward drug reactions.     

Processing capacity and switching attention in dichotic listening.

Describes 4 experiments with 82 undergraduates which indicate that (a) switching attention in a dichotic listening task requires processing capacity, and (b) increasing encoding difficulty reduces the amount of switching in a free recall dichotic listening task. Results are discussed in terms of a limited capacity processor model which contends that switching attention, encoding, and sustaining material all require processing capacity and that the S's strategy regarding switching attention is determined by the capacity available after capacity requirements for encoding are met. (French summary) (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemisphere-specific interference in dichotic listening: Task variables and individual differences.

In Exps I and II, 214 right-handed college students were required to identify dichotically presented CV syllables with either no concurrent memory (CM) load or with a CM load of 6 low-imagery nouns. Based on performance on their initial set of no-load trials, Ss were assigned to either a right-, left-, or no-ear advantage (REA, LEA, or NEA) group. Results for the REA group were similar to the results of previous studies of visual laterality and concurrent activity: Introducing a CM load of 6 words reduced recognition of right-ear CVs but not left-ear CVs. Furthermore, these effects persisted across 2 blocks of no-load and memory-load trials. This Memory Load?×?Ear interaction was weaker in the NEA group and tended to be reversed in the LEA group. About 10% of Ss showed a consistent LEA for CV recognition, and, for these Ss, introducing a CM load of 6 words reduced recognition of left-ear CVs but did not change the recognition of right-ear CVs. Again, these effects persisted across 2 blocks of no-load and memory load trials. Exp III (48 Ss) was similar to Exps I and II except that the CM task involved nonsense shapes that could probably be processed by either hemisphere. Introducing this concurrent nonverbal memory task did not reduce the recognition of either right- or left-ear CVs. Results indicate that the verbal nature of the concurrent task appears to be critical, as in previous visual laterality experiments. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the interaction of numerical and size information in digit comparison: a behavioral and event-related potential study

To investigate effects of dimensional congruity in digit comparison processes we recorded response latencies, error rates and event-related potentials (ERPs) in a situation when the relevant and the irrelevant dimension of judgement, the digit's physical size or its numerical value, varied unpredictably from trial to trial. Congruity effects may arise at early processing stages, where both numerical and size information are mapped onto a common, integrated representation. Alternatively, numerical and size information may be processed in functionally independent channels and interact only at a later stage of response activation. For both, numerical and size comparisons, reliable distance effects on ERPs (starting 224 ms post-stimulus at frontal electrode sites) and on behavioral data were observed. Congruity effects follow a timecourse that mirror-images the temporal pattern found for the distance effects: while distance effects on difference potentials start about 64 ms earlier for numerical comparisons, congruity effects due to the irrelevant attribute are seen about 88 ms earlier for size comparisons. While Lateralized Readiness Potentials (LRPs) for incongruent trials are shifted in time, there was no indication of an activation for the incorrect response in incongruent trials, as an account of congruity effects in terms of response competition would predict. The most parsimonious explanation of our results is that numerical and size information are extracted in parallel, are both converted into an integrated representation and potentially interact during these early parallel stages.     

Retrieval tags and order of report in dichotic listening.

To explain the effects of varying the rate of presentation on order of report in dichotic listening, a retrieval tag model must consider 2 kinds of tag, side and temporal position, and must include a mechanism sensitive to the rate manipulation to alter the relative usefulness of the 2 tags. 2 absolute judgment experiments with undergraduates (N = 32) yielded no evidence that the relative usefulness of the tags is altered passively by a rate manipulation. Results are interpreted as evidence against a model which considers only retrieval operations, and an alternate model encorporating both attention operations and retrieval operations is suggested. (French summary) (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endogenous and exogenous control of attention in dichotic listening.

Dichotic listening to verbal stimuli results in a right ear advantage (REA), indicating a left hemisphere processing superiority. The magnitude of the REA can be modulated by instructions to direct attention to the left or right ear stimulus. A previous study from our laboratory showed that presenting a prime syllable before the presentation of the dichotic syllables increases reports of the nonprimed syllable, apparently a negative priming effect that inhibits attention to the distracting prime representation. The present study combined attention instruction and priming, making up a 3 × 3 factorial design. The prime stimulus was a single consonant-vowel syllable presented binaurally just before onset of the dichotic consonant-vowel syllables. Results showed that both instructions and priming manipulations had an effect on which dichotic stimulus was selected. There was also a significant interaction between attention instruction and priming manipulation, indicating that the mechanism for instructed attention and the mechanism for negative priming work on the same level of processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the perception of sarcasm in dichotic listening.

The purpose of the present study was to investigate the processing of sincere and sarcastic statements by the cerebral hemispheres. Forty right-handed students were asked to localize sincere and sarcastic statements presented dichotically. Participants either indicated the ear that perceived the sarcastic statement or the ear that perceived the sincere statement in counterbalanced blocks of trials. As expected, results revealed a left ear advantage for sarcastic statements and a right ear advantage for sincere statements. In addition, participants showed faster response time when localizing targets (both sarcastic and sincere) to the left ear compared to the right. Finally, a significant negative correlation between laterality effects in the two tasks provided support for causal hemispheric complementarity. Results are discussed with reference to the contribution of the right and left hemispheres to language processing. Their implications for models of sarcasm perception are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response-monitoring dysfunction in schizophrenia: An event-related brain potential study.

Error-monitoring abnormalities may underlie positive symptoms of schizophrenia. Response-synchronized event-related potentials during picture-word matching yielded error- and correct-response-related negativity (ERN, CRN) and positivity (Pe, Pc) and preresponse lateralized readiness potentials (LRP) from 18 schizophrenic patients and 18 controls. Both groups responded faster to matches than nonmatches, although patients were generally slower and made more errors to nonmatches. Compared with controls, patients, particularly with paranoid subtype, had smaller ERNs and larger CRNs, which were indistinguishable. LRPs showed evidence of more response conflict before errors than before correct responses in controls but not patients. Despite ERN/CRN abnormalities, post-error slowing and Pe were normal in patients, suggesting a dissociation of ERN and error awareness. Anterior cingulate and dorsolateral prefrontal cortical dysfunction in schizophrenia are implicated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal and music dichotic listening tasks reveal variations in functional cerebral asymmetry across the menstrual cycle that are phase and task dependent

BACKGROUND: One of the key factors in maintaining optimal cognitive performance in the high-G environment is the adequate delivery of oxygen to the cerebral tissue. As eye-level blood pressure is compromised at 22 mmHg x G(-1), perfusion to the peripheral cerebral tissues (cerebral cortex) may not be adequate to support the mental demands of flight. This study measured the effect of closed-loop flight simulations (3 min) on cerebral oxygen saturation changes (rSO2), arterial oxygen saturation (SAO2), and heart rate (HR), in both rested (8 h of rest) and sleepless (24 h without sleep) conditions. METHODS: Subjects (16; 8 males and 8 females) were subjected to G-exposures via closed-loop flight simulations in a series of four 3-min sorties flown by subjects on the Dynamic Environment Simulator (centrifuge) in either a rested or a sleepless state. Prior to the centrifuge flight, subjects were instrumented with sensors for measurement of arterial oxygen saturation (SAO2) and regional cerebral tissue oxygenation (rSO2). Subjects wore the standard flight suit, boots, CSU-13B/P anti-G suit, and the COMBAT EDGE positive-pressure breathing for G-protection system. RESULTS: Significant changes in cerebral and arterial oxygen saturation were observed within groups when comparing pretest baselines and minimum values during the test and pre- and post-G rSO2, SAO2, and HR in both the rested and sleepless state, (p # 0.01), respectively, for each group. Comparisons between groups showed women to have significantly smaller regional cerebral cortex oxygen decreases than men (p # 0.01). No significant changes in SAO2, however, were observed between groups. Both men and women showed a slow recovery of rSO2 values to the prebaseline levels. CONCLUSIONS: Sleeplessness had no effect on the rSO2, SAO2, and HR compared with the rested condition. During acceleration, regional cerebral tissue oxygen decreased 13% in men compared with 9% in women. The recovery of cerebral tissue oxygen levels to prebaseline values was retarded somewhat when compared with the recovery response of arterial oxygen saturation.     

Stages of auditory feature conjunction: An event-related brain potential study.

Auditory event-related brain potentials (ERPs) were recorded to tones of different frequencies and locations in a dichotic selective attention task in which Ss responded to occasional deviant tones of a prespecified location and frequency. Attention effects were isolated as negative difference (Nd) waves by subtracting ERPs to tones with no attended features from ERPs to the same tones when they shared target frequency, location, or both cues. The N1/P90 (latency 80–200 msec), originating in a tonotopically organized generator, was enhanced for all tones in the attended ear. Nd waves, beginning at 80 msec and lasting up to 700 ms, were seen to tones with either attended feature. Nd waves to frequency and location features had different scalp distributions consistent with generation in different cortical fields. Conjunction-specific Nds began 30–50 msec after Nds to individual features. The relative timing suggests that feature conjunction began before the analysis of individual features was complete. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reliability and magnitude of perceptual asymmetries in a dichotic word recognition task.

The hypothesis that control of idiosyncratic attention deployment and retrieval strategies would improve the reliability and magnitude of laterality effects obtained in an auditory word recognition task was investigated. Sixty participants completed a dichotic word recognition task under 1 of 3 conditions. In free recall, they reported the 2 words presented on each trial (1 to each ear). In focused attention, they reported only the word presented to a prespecified ear. In target detection, they indicated whether a target word was presented to either ear on each trial. Results showed that the target-detection condition produced the largest and most reliable laterality effects compared with the other 2 conditions. The mechanisms likely to be responsible for these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)