Disjunctive Reaction Time Task Research Articles

Beat-to-beat control of human optokinetic nystagmus slow phase durations.

This study provides the first clear evidence that the generation of optokinetic nystagmus (OKN) fast phases is a decision process that is influenced by performance of a concurrent disjunctive reaction time task (DRT). The slow phase (SP) durations are consistent with a Gaussian basic interval generator and multiple interval SP durations occur more frequently in the presence of the DRT. Hence, OKN shows dual-task interference in a manner observed in voluntary movements, such as saccades.

The influence of cognitive tasks on vestibular-induced eye movements in young and older adults

The purpose of this study was to further investigate the mechanism of the influence of concurrent cognitive tasks on eye movements induced by earth-vertical axis rotation (EVAR) in young and older participants. Ten young (ages 21–34), ten young-old (ages 65–74) and nine older participants (ages 75–84) each performed five different cognitive tasks during sinusoidal EVAR in darkness at 0.02 Hz for three cycles, 0.05 Hz for four cycles, and 0.1 Hz for five cycles, all at a peak velocity of 50 degrees per second. The five tasks differed from one another in terms of their inherent sensory and motor components and were designed to provide insight into the effect of cognitive processing on VOR dynamics. Tasks included auditory frequency and lateralization disjunctive reaction time (DRT) tasks, silent and audible backward counting, and a question-response clinical standard task. For the DRT trials, tones were presented to the participant through earphones. Participants were instructed to respond as accurately and as quickly as possible. Eye movements were recorded with electro-oculography and calibrations were performed before and after every five rotations in all subjects. Participants had an increase in VOR phase lead while performing DRT tasks as compared to the clinical standard and counting tasks. The effect was most noticeable at the 0.02 Hz frequency and was present in all age groups. In addition, we observed a decrease in VOR gain while subjects performed auditory DRT tasks during EVAR at 0.02 Hz, 0.05 Hz and 0.1 Hz as compared to the clinical standard and counting tasks. These results suggest cognitive task-dependent interference between central auditory processing and vestibular processing primarily at the sensory rather than at the motor level.

Effects of aging on event-related brain potentials and reaction times in an auditory oddball task.

Auditory event-related potentials (ERPs) were recorded from 71 healthy individuals between 18 and 82 years of age during performance of a disjunctive reaction time task in an auditory oddball paradigm. The effects of aging on reaction times and on the latencies, amplitudes, and distributions of each of the main ERP components were examined. No significant slowing of the reaction times of the elderly subjects was observed in relation to the younger ones. The peak latencies of both the N1 and P2 components elicited by standard tones were slightly but significantly slowed with age. In the ERPs of target tones, the later, endogenous components (N2, P3, and SW) showed linear increases in latency as a function of age; the later the component, the longer the age-related delay. In general, aging was associated with less negativity (both N2 and SW) and more positivity (P3) over the anterior scalp, together with a smaller P3 and a more pronounced N2 over posterior scalp areas. Most of the effects observed in target ERPs were also evident in the difference waves derived from subtraction of the standard from the target ERPs, although the slope of the age-related latency increase of N2 was shallower and that of the P3 was steeper in the difference ERPs. These findings are discussed in relation to previous accounts of ERP changes with aging.

Longitudinal Analysis of Age Changes in Speed of Behavior

From 1973 to 1989, 1318 subjects ranging in age from 20 to 96 years completed auditory reaction time (RT) tasks as part of the extensive test battery of the Baltimore Longitudinal Study of Aging. In addition to central tendency, higher moments of reaction time frequency distributions (variability and skewness) were analyzed to (1) determine changes in the shape of the frequency distribution not revealed by analysis of central tendency alone, which could explain a portion of the slowing effect, and (2) examine differences in cross-sectional and longitudinal approaches. Cross-sectional results revealed significant age increases for median simple reaction time (SRT) and median disjunctive reaction time (DRT), as well as SRT and DRT variance. Males were significantly faster and less variable than females for both SRT and DRT tasks. SRT distributions were much more positively skewed than DRT distributions, and DRT distributions became more positively skewed with age. Increased variability appears to account for a sizable portion of the age-related performance slowing. Longitudinal analyses produced slightly different results, the most distinctive being the fading of age and sex differences over longer periods of time for median RT, variance, and skewness. Findings from this research have human factors implications for task design, personnel selection, accident analysis, and demographic norms.

Perceptual reactance and task performance.

57 female subjects participated in a study in which perceptual reactance was assessed by the kinesthetic figural aftereffects test. Subjects identified as augmenters were quicker than reducers on a disjunctive reaction time task and a significant interactive effect was found on a paired-associate task. Augmenters performed better on a similar list while reducers were more effective on a dissimilar list.

Attention and cardiac activity: Heart rate responses during a variable foreperiod, disjunctive reaction time task

A variable foreperiod disjunctive reaction time task was used to evaluate the effects of stimulus discriminability on cardiac activity. In two sessions, 20 male undergraduates received easy or difficult auditory discrimination trials in blocked and random series. In the random session only, when the warning stimulus provided information about the difficulty of the subsequent discrimination, difficult trials were associated with greater foreperiod deceleration. Cardiac accelerations also tended to be greater in the foreperiods of difficult trials. There was an effect of both warning and imperative stimuli on the heart rate of the cycle in which the stimuli occurred which depended on the difficulty of the trial. The results are discussed in terms of the psychological significance of the different heart rate responses.

‘Women’s will to fail’ in a disjunctive reaction time competitive task

Horner’s ‘women’s will to fail’ hypothesis was tested with a disjunctive reaction time task, using students from a church-related college divided into three equal groups: tested alone (F), competing against a male confederate (F-M), and competing against a female confederate (F-F). Group F reacted significantly slower than F-F (p < .01) and F-M (p < .05), and Group F-M reacted significantly slower than F-F (p <.05). The hypothesis that women in a competitive task with a male do not perform as well as when competing with another female was supported.

Heart rate and disjunctive reaction time: the effects of discrimination requirements.

In three experiments, 5s were given series of easy or difficult auditory discriminations in the context of a fixed foreperiod disjunctive reaction time task. Tonic heart rate was slower during series of difficult trials than during series of easy trials, when they were presented in separate sessions. When they were given in two halves of the same session, this result was not replicated. When easy and difficult trials were presented'in a random order, and information was provided at the beginning of the foreperiod about the difficulty of that trial, phasic deceleration was greater on difficult trials. Peak-to-trough change was negatively related to reaction time in all experiments. The results are discussed in terms of Lacey's intake-rejection hypothesis.

Changes of antero-posterior distribution of CNV and late positive component as a function of information processing demands.

ABSTRACTThe topographic distribution of the amplitudes of the contingent negative variation (CNV) recorded along the midline at the anterior, central, and posterior regions of the human scalp varied as a function of type of information processing demanded. A parietal‐dominant CNV was found when active problem‐solving behavior was required. A central‐dominant CNV was evident in a disjunctive reaction time task. The results are interpreted as evidence supporting a model of cortical function which predicts shifts in cortical involvement as a function of type of task demands. A late positive component (LPC) of the average evoked potential was also found to vary as a function of stage of learning, recording sites, and an attitudinal dimension measured by Rotter's internal‐external locus of control scale.

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.

Proactive decremental effects on response speed in a continuous DRT task

Thirty Ss performed a 324-trial, subject-paced, two-signal, frequency-imbalaneed, disjunctive reaction time task. Responses on trials following the occurrence of the infrequent signal yielded longer RTs than responses on other trials. This effect is attributed to novelty produced “startle,” and is different from series effects previously reported.