Psychopathy and the allocation of attentional capacity in a divided-attention situation.

Investigated the hypothesis that psychopaths allocate most of their attentional capacity to stimuli and responses of immediate interest by assessing psychopaths' dual-task performance under 2 instructional sets. Using R. D. Hare's (see record 1985-22847-001) psychopathology checklist, 72 White male prison inmates (approximate mean age 25 yrs) were classified as psychopaths or nonpsychopaths. It was hypothesized that psychopaths would divide attention adequately between a visual search and probe reaction time (RT) task, but that when instructions defined the search as Ss' primary task, psychopaths would overfocus on it and outperform nonpsychopaths at the cost of relatively poor secondary task performance. Results challenge the validity of the overfocusing hypothesis. S groups performed equally well on the search when it received instructional priority, but psychopaths made more search errors under divided-attention instructions. Psychopaths also responded more slowly than nonpsychopaths to auditory probes across conditions. Results suggest that psychopaths may incur relatively large capacity costs in attempting to shift their attentional resources between processing tasks. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sustained attention in the mouse: A study of the relationship with the cerebellum.

To explore the role of the cerebellum in sustained attention, the authors tested lurcher, wildtype, and lurcher chimeric mice with zero, normal, and variable numbers of Purkinje cells, respectively, in a previously validated task of sustained attention. Results indicate that lurcher mice had a deficit in performance likely related to their motor disability, whereas lurcher chimeras performed similarly to wildtype controls. Presentation of auditory or visual distracters caused deficits in the performance of all mice that were specific to either signal (auditory) or nonsignal (visual) events. The authors' results do not support a role of the cerebellum in sustained attention, instead indicating that behavioral changes are an indirect result of motor deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Covert auditory spatial orienting: An evaluation of the spatial relevance hypothesis.

The spatial relevance hypothesis (J. J. McDonald & L. M. Ward, 1999) proposes that covert auditory spatial orienting can only be beneficial to auditory processing when task stimuli are encoded spatially. We present a series of experiments that evaluate 2 key aspects of the hypothesis: (a) that “reflexive activation of location-sensitive neurons is not sufficient to produce attentional facilitation” and (b) that “any task constraint that makes space important for the listener will produce auditory spatial cue effects” (p. 1236). Experiment 1 showed significant reflexive-orienting benefits on a nonspatial task, refuting the first claim. However, Experiments 2 to 4 reveal that informative spatial cues can improve performance on a nonspatial task, consistent with the second claim. Auditory spatial-cue benefits found with nonspatial tasks appear smaller and less reliable than those found in visual spatial-orienting studies, possibly due to differences in the coding of spatial information in vision and audition. The final experiments consider the mechanisms by which auditory spatial orienting might facilitate auditory processing and provide tentative evidence that attention enhances processing at one ear rather than influencing neurons tuned to the attended location. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Socialization and attentional deficits under focusing and divided attention conditions.

Conducted two studies to test and refine the hypothesis that, when undersocialized individuals focus on events of immediate interest, they allocate too large a proportion of their processing resources to those events and have little attention available for processing other important events. College students who completed the Socialization (So) scale (Gough, 1960) performed visual and auditory tasks simultaneously under conditions favoring the visual task, an equal division of processing resources between the tasks, or both. In both studies, low-So Ss performed relatively poorly on the auditory task under focusing conditions but displayed no primary task advantage and no significant performance deficits under divided attention conditions. These data support the utility of theories relating antisocial behavior to individual differences in allocation of attention. Low-So Ss' unresponsiveness to secondary events is not a simple function of the reallocation of resources to the primary task or a speed–accuracy trade-off. Moreover, under certain conditions, this deficit may disappear, given substantial practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Now you see it, now you don't: Evidence for age-dependent and age-independent cross-modal distraction.

Age-related deficits in selective attention have often been demonstrated in the visual modality and, to a lesser extent, in the auditory modality. In contrast, a mounting body of evidence has suggested that cross-modal selective attention is intact in aging, especially in visual tasks that require ignoring the auditory modality. Our goal in this study was to investigate age-related differences in the ability to ignore cross-modal auditory and visual distraction and to assess the role of cognitive control demands thereby. In a set of two experiments, 30 young (mean age = 23.3 years) and 30 older adults (mean age = 67.7 years) performed a visual and an auditory n-back task (0 ≤ n ≤ 2), with and without cross-modal distraction. The results show an asymmetry in cross-modal distraction as a function of sensory modality and age: Whereas auditory distraction did not disrupt performance on the visual task in either age group, visual distraction disrupted performance on the auditory task in both age groups. Most important, however, visual distraction was disproportionately larger in older adults. These results suggest that age-related distraction is modality dependent, such that suppression of cross-modal auditory distraction is preserved and suppression of cross-modal visual distraction is impaired in aging. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Divided attention in youth-onset psychosis and attention deficit/hyperactivity disorder.

The authors used pupillary dilations to test whether divided attention deficits in youth-onset psychosis and attention deficit/hyperactivity disorder (ADHD) were because of limitations in recruitment of cognitive resources or abnormalities in attention allocation. Eight- to 19-year-olds with youth-onset psychosis or ADHD were administered a divided attention test consisting of an auditory digit span (DS) task and a simple visual response time (RT) task. In 4 conditions, participants performed neither (no task), 1 (DS or RT only), or both tasks (dual). Dependent variables were DS accuracy, RT, and pupillary dilation to digits as an estimate of recruitment of cognitive resources. The authors found no evidence for an abnormal attention strategy in either disorder. Instead, results were consistent with the hypothesis that both clinical groups have limitations in resource recruitment. These limitations were more severe in psychosis than in ADHD. Findings indicate that both clinical groups had difficulties in regulating physiological arousal on a moment-to-moment basis in accordance with task demands. Findings also demonstrate the importance of taking into account difficulties that constrain performance on simple tasks before interpreting impairments on complex tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of age on working memory: an event-related potential study

The effects of age on behavioural performance and event-related potentials recorded during a working memory task using digits presented either acoustically or visually, were studied in 37 healthy subjects with an age range from 19 to 71 years. With increasing age, psychological tests showed a progressive decline in visuo-spatial performance and both auditory and visual reaction times (RT) increased. There were multiple and varying effects of age on both early and late ERP components. For both auditory and visual responses, increasing age was associated with an increased amplitude of early positive waves (auditory P100 and visual P145) and, in the oldest subjects, significant delays of the major late positive waves. Other changes were modality-specific with a progressive shift of amplitude maxima in the early negative waves of the visual ERPs (from an N190 peak maximal at Pz in the young, to an N270 peak maximal at Cz in the older subjects) and an altered amplitude distribution of late potentials (after the P250 wave) in the auditory responses. The age at which ERP changes occurred varied-significant latency prolongations and increases in the amplitude of the major frontal positive waves occurred only in the oldest subjects, whereas a redistribution of late auditory ERPs also occurred in the intermediate age group. There was no interaction between age and increasing memory load, suggesting that there is no specific effect of age on memory scanning in this age range for these levels of task difficulty. Thus, although performance in working memory was apparently unaffected by age, as judged by behavioural parameters (apart from slowing of the reaction times), ERPs revealed significant changes in both early and late electrical brain processes associated with working memory as age increases. These changes which were not symptomatically manifest and only revealed by sensitive tests, may represent subtle dysfunction of working memory (or associated processes) which does not prevent the successful completion of our task, compensatory mechanisms (which are essential to successfully complete the task), or a combination of both age-induced dysfunction and compensatory mechanisms.     

Supramodal and modality-specific mechanisms for stimulus-driven shifts of auditory and visual attention.

Describes 2 experiments in which visual and/or auditory location precues preceded visual or auditory targets. 30 observers were required to judge the location of the targets. Conditions were such that involuntary, stimulus-driven (SD) attention shifts were the only ones likely to occur and give rise to cueing effects. It was found that visual precues affected response time to localize both visual targets and auditory targets, but auditory precues affected only the time to localize auditory targets. Moreover, when visual and auditory cues conflicted, visual cues dominated in the visual task but were dominated by auditory cues in the auditory task. Results suggest that involuntary SD attention shifts might be controlled by a modality-specific mechanism for visual tasks, whereas SD shifts of auditory attention are controlled by a supramodal mechanism. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heterogeneity of auditory verbal working memory in schizophrenia.

The heterogeneity of schizophrenia remains an obstacle for understanding its pathophysiology. Studies using a tone discrimination screening test to classify patients have found evidence for 2 subgroups having either a specific deficit in verbal working memory (WM) or deficits in both verbal and nonverbal memory. This study aimed to (a) replicate in larger samples differences between these subgroups in auditory verbal WM; (b) evaluate their performance on tests of explicit memory and sustained attention; (c) determine the relation of verbal WM deficits to auditory hallucinations and other symptoms; and (d) examine medication effects. The verbal WM and tone discrimination performance did not differ between medicated (n = 45) and unmedicated (n = 38) patients. Patients with schizophrenia who passed the tone screening test (discriminators; n = 60) were compared with those who did not (nondiscriminators; n = 23) and healthy controls (n = 47). The discriminator subgroup showed poorer verbal WM than did controls and a deficit in verbal but not visual memory on the Wechsler Memory Scale–Revised (Wechsler, 1987), whereas the nondiscriminator subgroup showed overall poorer performance on both verbal and nonverbal tests and a marked deficit in sustained attention. Verbal WM deficits in discriminators were correlated with auditory hallucinations but not with negative symptoms. The results are consistent with a verbal memory deficit in a subgroup of schizophrenia having intact auditory perception, which may stem from dysfunction of language-related cortical regions, and a more generalized cognitive deficit in a subgroup having auditory perceptual and attentional dysfunction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Isolation of a cytokinin gene, ZOG1, encoding zeatin O-glucosyltransferase from Phaseolus lunatus

University students who were skilled or less-skilled readers were compared on tests of auditory information processing and immediate serial recall of auditory and visual digits. Reading skill was defined by performance on a pseudoword reading task. The good readers exhibited typical modality effects with higher recall of auditory than visual items from the last 3 serial positions. On the terminal list item, the less-skilled readers showed a modality effect comparable with that of the skilled readers, but on other list items the modality effect reversed and a visual superiority was obtained. Results were discussed in terms of C. G. Penney's (1989) separate-streams model of short-term verbal memory.     

Unusual modality effects in less-skilled readers.

University students who were skilled or less-skilled readers were compared on tests of auditory information processing and immediate serial recall of auditory and visual digits. Reading skill was defined by performance on a pseudoword reading task. The good readers exhibited typical modality effects with higher recall of auditory than visual items from the last 3 serial positions. On the terminal list item, the less-skilled readers showed a modality effect comparable with that of the skilled readers, but on other list items the modality effect reversed and a visual superiority was obtained. Results were discussed in terms of C. G. Penney's (1989) separate-streams model of short-term verbal memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The temporal dynamics of visual search: Evidence for parallel processing in feature and conjunction searches.

Feature and conjunction searches have been argued to delineate parallel and serial operations in visual processing. The authors evaluated this claim by examining the temporal dynamics of the detection of features and conjunctions. The 1st experiment used a reaction time (RT) task to replicate standard mean RT patterns and to examine the shapes of the RT distributions. The 2nd experiment used the response-signal speed-accuracy trade-off (SAT) procedure to measure discrimination (asymptotic detection accuracy) and detection speed (processing dynamics). Set size affected discrimination in both feature and conjunction searches but affected detection speed only in the latter. Fits of models to the SAT data that included a serial component overpredicted the magnitude of the observed dynamics differences. The authors concluded that both features and conjunctions are detected in parallel. Implications for the role of attention in visual processing are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A dual-task investigation of automaticity in visual word processing.

An analysis of activation models of visual word processing suggests that frequency-sensitive forms of lexical processing should proceed normally while unattended. This hypothesis was tested by having participants perform a speeded pitch discrimination task followed by lexical decisions or word naming. As the stimulus onset asynchrony between the tasks was reduced, lexical-decision and naming latencies increased dramatically. Word-frequency effects were additive with the increase, indicating that frequency-sensitive processing was subject to postponement while attention was devoted to the other task. Either (a) the same neural hardware shares responsibility for lexical processing and central stages of choice reaction time (RT) task processing and cannot perform both computations simultaneously, or (b) lexical processing is blocked in order to optimize performance on the pitch discrimination task. Either way, word processing is not as automatic as activation models suggest. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning to bypass the central bottleneck: Declining automaticity with advancing age.

Does advancing age reduce the ability to bypass the central bottleneck through task automatization? To answer this question, the authors asked 12 older adults and 20 young adults to first learn to perform an auditory–vocal task (low vs. high pitch) in 6 single-task sessions. Their dual-task performance was then assessed with a psychological refractory period paradigm, in which the highly practiced auditory–vocal task was presented as Task 2, along with an unpracticed visual–manual Task 1. Converging evidence indicated qualitative differences in dual-task performance with age: Whereas the vast majority of young adults bypassed the bottleneck, at most 1 of the 12 older adults was able to do so. Older adults are either reluctant to bypass the bottleneck (as a matter of strategy) or have lost the ability to automatize task performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related changes in processing auditory stimuli during visual attention: Evidence for deficits in inhibitory control and sensory memory.

Age-related declines in attention and cognition have been associated with a difficulty in inhibiting the processing of task-irrelevant information (i.e., the inhibitory deficit hypothesis). However, evidence supporting the inhibitory deficit hypothesis remains equivocal, in part because of complexities in examining the processing of irrelevant stimuli using purely behavioral techniques. The effects of age on the processing of task-irrelevant stimuli were examined using scalp-recorded event-related brain potentials. Participants performed a visual discrimination task while standard and deviant auditory stimuli were presented in the background. Deviant auditory stimuli generated a mismatch negativity (MMN) wave that decreased with age, in part because of an age-related enhancement in sensory-evoked responses. The age-related changes in processing task-irrelevant auditory stimuli are consistent with the inhibitory deficit hypothesis and suggest that impaired inhibitory control of sensory input may play a role in the age-related declines in performance during selective attention tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Switching in the cocktail party: Exploring intentional control of auditory selective attention.

Using a novel variant of dichotic selective listening, we examined the control of auditory selective attention. In our task, subjects had to respond selectively to one of two simultaneously presented auditory stimuli (number words), always spoken by a female and a male speaker, by performing a numerical size categorization. The gender of the task-relevant speaker could change, as indicated by a visual cue prior to auditory stimulus onset. Three experiments show clear performance costs with instructed attention switches. Experiment 2 varied the cuing interval to examine advance preparation for an attention switch. Experiment 3 additionally isolated auditory switch costs from visual cue priming by using two cues for each gender, so that gender repetition could be indicated by a changed cue. Experiment 2 showed that switch costs decreased with prolonged cuing intervals, but Experiment 3 revealed that preparation did not affect auditory switch costs but only visual cue priming. Moreover, incongruent numerical categories in competing auditory stimuli produced interference and substantially increased error rates, suggesting continued processing of task-relevant information that often leads to responding to the incorrect auditory source. Together, the data show clear limitations in advance preparation of auditory attention switches and suggest a considerable degree of inertia in intentional control of auditory selection criteria. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Aerobic fitness and psychophysiological reactivity.

Examined the pattern of psychophysiological response to a demanding cognitive task in 10 males and 9 females (aged 35–45 yrs) of different aerobic fitness levels. Following baseline measures of heart rate and skin conductance, Ss performed a task with cognitive, motor, visual, and auditory components that caused an information processing system overload argued to be psychologically stressful. Aerobic fitness level was correlated with psychophysiological reactivity during and following exposure to the task. Fitness level was unrelated to heart rate and skin conductance level during the task but was positively correlated with speed of recovery to baseline once the task terminated. Within individual Ss, the 2 psychophysiological indices followed different time courses during recovery, but the rates of recovery were positively correlated. The quicker psychophysiological recovery of the aerobically fitter Ss may mediate certain psychological adaptations associated with improved physical fitness. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory in young children: evidence for modality-specificity and implications for cerebral reorganization in early childhood

Digit span (DS) and visual-spatial memory span (VMS) tasks have been considered indices of auditory and visual spatial processing, respectively, often classified as "primary memory" or "attention". There has been limited evidence for their modality specificity, however. We present two children who showed visual spatial processing deficiencies (including VMS) and non-dominant manual inefficiency with normal visual-spatial perception, auditory-verbal processing and dominant fine manual skills. These children support a distinction between auditory and visual-spatial memory span. These findings are discussed with regard to a hypothesis that the unique expression of VMS is time-limited, that visual-spatial processing becomes more verbalized as children learn to read and that these behavioral changes produce a lateral shift in cortical processing of visual spatial information.     

Psychopathy and dual-task performance under focusing conditions

Thirty psychopathic and 30 nonpsychopathic right-handed White male inmates (selected through R.D. Hare's, 1985b, Psychopathy Checklist) completed concurrent visual and auditory tasks under conditions focusing attention on the visual (i.e., primary) task. Performance indices tested 3 related hypotheses for cognitive deficits in psychopathic individuals: reduced attention to secondary tasks because of excess attention to immediate goals (interference), deficient shifts of attention, and reduced breadth of attention. The absence of differences in primary and secondary task accuracy contradicts the interference hypothesis. However, a trend toward deficits for psychopathic individuals responding with the right hand to primary task targets appearing after other targets, suggests poorer shifting of attention when left-hemisphere resources are engaged. Psychopathic individuals also overresponded to distractors following targets suggesting reduced attention to a peripheral dimension of two-dimensional stimuli.     

Word and tone working memory deficits in schizophrenia

BACKGROUND: Verbal memory deficits have been reported in many studies of patients with schizophrenia. We evaluated the specificity of these deficits by comparing patients and control subjects on several verbal and nonverbal auditory memory tests. METHODS: Performance of stable, medicated outpatients with DSM-III-R diagnoses of schizophrenia (N = 38) was compared with that of healthy subjects (N = 39) on a word list immediate recall task, tone delayed discrimination tasks, and word and tone serial position tasks. Before memory testing, patients were divided into 2 groups based on their ability to perform normally on a screening test requiring pitch discrimination and sustained attention. RESULTS: The nonverbal tests were more difficult for control subjects than the verbal tests. Despite this, patients who performed normally on the screening test of perception and attention performed normally on both nonverbal tests but had highly significant deficits on both verbal tests (P<.001 and P = .02). Patients who performed poorly on the screening test had highly significant performance deficits on all the memory tests. CONCLUSIONS: One subgroup of patients with schizophrenia has a selective deficit in verbal memory despite normal motivation, attention, and general perceptual function. Another group has deficits in multiple aspects of cognitive function suggestive of failure in early stages of information processing.