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)     

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)     

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)     

Attentional strategies in dichotic listening.

Describes 2 experiments in which a total of 48 college students heard series of 3 dichotic word-digit pairs and were instructed to recall them either by ears or by types. Recall instructions were given before each block of 12 series, before each individual series, or after each series. With preinstruction, serial position effects were rather flat for the 1st-reported channel but showed a marked recency effect for the 2nd-reported channel, suggesting that the Ss attended mainly to the lst channel. With postinstruction, serial position effects were parallel for the 2 channels. Results were practically the same whether channels represented ears or types, suggesting that attention played the same role in each case. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binaural competition and division of attention as determinants of the laterality effect in dichotic listening.

In the normal dichotic listening procedure, there is competition between 2 inputs arriving simultaneously. Also, S must attend to both ears at the same time. In a series of 4 experiments, with over 80 undergraduates, these 2 factors were manipulated independently to assess their relative contributions to the laterality effect. In the 1st 3 experiments, conditions were employed in which the input was always monaurally presented, but the S did not know in advance where the material would arrive. In Exp. IV, the preinstruction condition provided a situation in which the S could direct his attention to a single channel. Results indicate that competition is both necessary and sufficient for a right-ear superiority to be observed. The necessity of attending to 2 channels at the same time does not seem to influence the laterality effect in any way. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory attention in hyperactive children: Effects of stimulant medication on dichotic listening performance.

Administered dichotic digit tasks requiring free report and selective listening, respectively, to 20 6–16 yr old hyperactive children. Ss received methylphenidate before 2 experimental sessions and a placebo before 2 control sessions. The stimulant did not improve free-report performance significantly; rather it facilitated or impaired performance, depending on how it affected the order in which stimuli were reported. Similarly, medication had no effect on overall selective-listening performance, but it increased the difficulty of switching attention from one ear to the other. Results demonstrate that stimulants may act to maintain selective attention and to inhibit channel switching. Listening asymmetry, that is, right-ear superiority, was influenced by task variables but not by stimulant medication. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Allocation of attention in dichotic listening: Differential effects on the detection and localization of signals.

In 2 dichotic listening experiments, 96 normal right-handed adults attended selectively to the left and right ear and divided their attention equally between both ears. Participants listened for specified targets and reported the ear of entry. The material consisted of pairs of consonant–vowel syllables in Experiment 1 and pairs of rhyming consonant–vowel–consonant words in Experiment 2. Both experiments yielded a right-ear advantage for detection and for localization. Attention instructions had no effect on detection. However, focusing attention on 1 ear increased the number of targets attributed to that ear while decreasing the number of targets attributed to the opposite ear. The dissociation between detection and localization indicates that volitional shifts of attention influence late (response selection) processes rather than early (stimulus identification) processes. Selective-listening effects can be accounted for by a 2-stage model in which a fixed input asymmetry is modulated by a biased selection of responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychopathy and perceptual asymmetry during verbal dichotic listening.

Administered a verbal dichotic listening (divided attention) task to 146 male prison inmates (mean age 30 yrs) and 159 male noncriminals (mean age 27.5 yrs). The inmates were divided into psychopathic (P), nonpsychopathic (NP), and mixed (M) groups on the basis of a psychopathy checklist and the DSM-III criteria for antisocial personality disorder. Group P exhibited a significantly smaller right-ear advantage (less lateralized performance) than did either Group NP or the noncriminals. When the task was administered to 48 inmates under instructions to focus attention on 1 ear at a time, the performance of Group P was again less lateralized than was that of Group NP. The possibility that language processes are not strongly lateralized in psychopaths and that psychopaths are characterized by asymmetric low left-hemisphere arousal is discussed. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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)     

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)     

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)     

Reduced lateralization in verbal dichotic listening in adolescent psychopaths.

One possible explanation for previous findings of abnormal linguistic processing in psychopaths is that they are less lateralized for verbal processes. This study tests the hypothesis that adolescent psychopaths show evidence of reduced lateralization on a verbal dichotic listening task. Four self-report and behavioral measures of psychopathy were used to define psychopathy using cluster analytic techniques in 40 juvenile offenders aged 13 to 18 years. Psychopaths were found to have reduced ear asymmetries relative to nonpsychopaths, a result indicating reduced lateralization for verbal material. The effect does not appear to be mediated by group differences in age, ethnic background, IQ, overall performance, left-handedness, selective attention to one ear, or interhemispheric transfer deficits. This result suggests that the previous finding by R. D. Hare and L. M. McPherson (see record 1984-23362-001) is robust, provides some preliminary validity for the assessment of psychopathy before age 18, and indicates initial support for the utility of cluster analytic techniques in the assessment of psychopathy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in dichotic listening with categorized word lists.

Two experiments examined the effects of blocking of word lists (grouped by semantic category membership or randomly ordered) on the dichotic listening performances of 48 2nd and 48 5th graders. For Exp I, shadowing and retention scores were obtained for groups of Ss representing the 4 combinations of blocked and random word lists for targets and distractors. Blocking of distractor lists led to better shadowing scores for 2nd graders. When word pairs were matched by categories in Exp II, 2nd graders who heard blocked lists recognized fewer target words (in retention tests) than did those who heard randomly ordered word lists. Results are interpreted in the context of variables that affect the shadowing performances of younger children and developmental differences in encoding strategies. (11 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)     

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)     

Development of three strategies of attention in dichotic monitoring.

Investigated 3 strategies of attention in 108 Ss in 3 age groups (7, 11, and 20 yrs). Ss monitored lists of monaural and dichotic words and responded manually to target words. Target detection rates in unequal division of attention (Exp I) showed that selection of the relevant input improved with age. The degree of attenuation of the irrelevant input was dependent on which ear was being ignored, but this effect interacted with age. The 7-yr-olds could not attend effectively to left-ear items. Exp II simplified the focusing strategy by eliminating response requirements to the irrelevant input. Selectivity improved with this strategy, particularly in 7-yr-olds. Equal division of attention between the 2 ears (Exp III) revealed a constant right-ear advantage in each age group. Differentiation of the 3 voluntary strategies improved between ages 7 and 11. In adults, the 3 strategies were clearly distinguished. Results are interpreted in terms of a multiprocess model of attention: Perceptual factors such as dichotic interaction and hemispheric asymmetry were strategy dependent but not age dependent. Voluntary selective attention was age dependent and affected the degree to which hemispheric asymmetry could be overcome. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Capture of attention in selective frequency listening.

Four signal-detection experiments demonstrated robust stimulus-driven, or exogenous, attentional processes in selective frequency listening. Detection of just-above-threshold signal tones was consistently better when the signal matched the frequency of an uninformative cue tone, even with relatively long cue-signal delays (Experiment 1) or when as few as 1 in 8 signals were at the cued frequency (Experiment 2). Experiments 3 and 4 compared performance with informative and uninformative cues. The involvement of intentional, or endogenous, processes was found to only slightly increase the size of the cuing effect beyond that evident with solely exogenous processes, although the attention band, a measure of how narrowly attention is focused, was found to be wider when cues were informative. The implications for models of auditory attention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Laterality effects for musical structure processing: A dichotic listening study.

Objective: Our study investigated hemispheric lateralization for musical structure processing using a dichotic listening paradigm with music and speech. Method: Eight chord sequences and 8 spoken syllable sequences were simultaneously presented, each to 1 ear. For the musical sequences, the final chord was expected (i.e., tonic) or less expected (i.e., subdominant). In addition to tonal function, which was task irrelevant, we manipulated the final syllable and the final timbre of the sequences for the experimental task: Participants were asked to identify the final syllable (/di/, /du/) or the timbre of the final chord (Timbre A or B). Results: Our experiment revealed a left-ear advantage for the tonal function effect on spoken syllable identification. For syllables presented to the right ear, identification was faster when the final chord of the musical sequence was a tonic chord rather than a subdominant chord (i.e., musical sequences presented to the left ear). Conclusions: The present finding extends the effect of musical structure previously observed for sung and visual syllable processing to spoken syllable processing. It further suggests a right-hemispheric specialization for the processing of musical structures in healthy listeners, as previously reported for split-brain patients (Tramo & Bharucha, 1991). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Irreversibility of imprinting after active versus passive exposure to the object.

64 isolated Peking ducklings were reared for 4 days with a hanging colored object (passive training). Half of the Ss also received 3 1-hr following sessions with the object (active training). Findings indicate that both groups chose the imprinting object in a simultaneous choice test administered on Day 5, but the preference of active-trained Ss was more robust than of passive-trained Ss. Each S was then reared with an object of a different color and shape. The preference for the 1st object was maintained in active-trained Ss, but not in passive-trained Ss. These results were also found when the objects were removed from the cages for 4 days. Findings suggest that preferences established during the sensitive period for imprinting can be eliminated (but not necessarily reversed) in Ss that are prevented from following the original object, but they are resistant to change in Ss given the following experience. A hypothesis is presented that emphasizes the importance of reafference and activation of brain stem pathways involved in following the formation of specific affiliative bonds. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical access without attention? Explorations using dichotic priming.

The authors used lexical decision in a dichotic listening situation and measured identity priming across channels to explore whether unattended stimuli can be processed lexically. In 6 experiments, temporal synchronization of prime and target words was manipulated, and acoustic saliency of the unattended prime was varied by embedding it in a carrier sentence or in babble speech. When the prime was acoustically salient, a cross-channel priming effect emerged, and participants were aware of the prime. When the prime was less salient, no identity priming was found, and participants failed to notice the prime. Saliency was manipulated in ways that did not degrade the prime. Results are inconsistent with models of late filtering, which predict equal priming irrespective of prime saliency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)