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Current evidence indicates a strong relation between improved visuomotor choice reaction time (VMRT) and a reduced risk of lower extremity injury, making both lower- and upper extremity VMRT training paradigms valuable to athletes. This investigation studied as yet unconfirmed crossover effects of upper extremity training on lower extremity performance; and we evaluated underlying relevant perceptual and cognitive adaptations. In this three-armed, randomized, controlled intervention, we used a computerized training device to compare participants receiving four weeks of upper ( n = 12) and lower ( n = 12) extremity VMRT training with a control group ( n = 13) of healthy participants. Collectively, our participants had a mean age of 24.6 years ( SD = 2.2), a mean height of 173 cm ( SD = 10), and a mean weight of 69.6 kg ( SD = 12.1); 57% ( n = 21) were female and 43% ( n = 16) were male. We assessed participants’ upper and lower extremity VMRT performance and domain-specific perceptual and cognitive abilities before and after intervention and analyzed differences between their before and after performances. Lower extremity training enhanced VMRT performances for both lower extremity and crossover upper extremity. Upper extremity training improved VMRT for upper extremity and increased cognitive choice reaction performance but yielded no crossover effects to lower extremity. We found no effects of VMRT training on other domain-specific cognitive performance markers (attention, executive function, memory, or working memory). VMRT training modulated only task-specific cognitive performance and induced crossover effects from lower extremity training to upper extremity performance but not vice versa.

Extending work by Montare, visual simple reaction time, choice reaction time, discriminative reaction time, and overall reaction time scores obtained from college students by the simplest chronoscope (a falling meterstick) method were significantly faster as well as significantly less variable than scores of the same individuals from electromechanical reaction timers (machine method). Results supported the existence of dual reaction time systems: an ancient primary reaction time system theoretically activating the V5 parietal area of the dorsal visual stream that evolved to process significantly faster sensory-motor reactions to sudden stimulations arising from environmental objects in motion, and a secondary reaction time system theoretically activating the V4 temporal area of the ventral visual stream that subsequently evolved to process significantly slower sensory-perceptual-motor reactions to sudden stimulations arising from motionless colored objects.

A total of 32 studies comprising 238 simple reaction time and choice reaction time conditions were examined in individuals with autism spectrum disorder (n = 964) and controls (n = 1032). A Brinley plot/multiple regression analysis was performed on mean reaction times, regressing autism spectrum disorder performance onto the control performance as a way to examine any generalized simple reaction time/choice reaction time slowing exhibited by the autism spectrum disorder group. The resulting regression equation was Y (autism spectrum disorder) = 0.99 × (control) + 87.93, which accounted for 92.3% of the variance. These results suggest that there are little if any simple reaction time/choice reaction time slowing in this sample of individual with autism spectrum disorder, in comparison with controls. While many cognitive and information processing domains are compromised in autism spectrum disorder, it appears that simple reaction time/choice reaction time remain relatively unaffected in autism spectrum disorder.

This experiment sought to determine whether breathing carbon dioxide (CO2), a toxic environmental stressor known to impair reaction time, slows human information processing in the stimulus encoding or response selection stage, or both, and whether this effect is influenced by time-on-task and exposure duration. In a 2 X 2 X 2 X 4 (Gas X Degradation X Compatibility X Time-on-Task) within-participants design, six highly practiced (more than 10,000 trials) healthy young male participants performed a serial choice reaction time (SCRT) task while breathing either 4% CO2 (with 50% O2) or room air (0.03% CO2 and 21% O2) for 60 minutes. Task variables manipulated were stimulus degradation (intact vs. degraded) and stimulus-response compatibility (high vs. low). Data from each 20-min SCRT test were subdivided into 5-min and 2-min intervals to determine the effects of time-on-task (and exposure duration). There were significant increases in SCRT from breathing carbon dioxide (p =.004), degrading the stimulus (p 2 at an undetectable concentration that did not produce clinical symptoms, (2) determined the locus of this effect was associated with the response selection stage of processing, (3) demonstrated that the progressive deterioration in performance due to increases in time-on-task (and exposure duration) affects both the stimulus encoding and response selection stages in a similar manner, and (4) ruled out alternative explanations by showing the results did not vary with distribution analyses, data trimming, error analyses, and analyses for tradeoffs of speed-accuracy, SCRT-DT, and other performance operating characteristics.

The study investigated the association of tennis playing and running with the psychomotor speed of older drivers. Thirty-six active male drivers ( M age = 63.2 yr.) participated. A battery of four on-the road driving tests was performed by tennis players, runners, and a control group. Measures of simple and choice reaction time, movement time, and response time were collected under single- and dual-task conditions. A composite driving score was calculated from reaction time measures of all driving tasks to reflect a general drivers' psychomotor speed. Statistically significant differences between groups were found in a braking task; tennis players performed significantly better than controls in simple reaction time and response time. The composite driving score also differed between groups, and tennis players had better results than controls. Regular participation in tennis was related to psychomotor speed of older drivers.

Although numerous studies have examined the facilitative and deleterious effects of monetary rewards on human behavior, little research (if any) has examined the connection between monetary rewards and choice reaction time (CRT) under varying stimulus–response (S–R) compatibility conditions. Twenty self-declared right-handed, undergraduate students, with an equal number of males and females in each group ( M age = 21.6 yr., SD = 2.13), were randomly assigned to one of two groups: monetary rewards or control. Participants in the monetary rewards group had a chance to draw for a cash prize of $30.00 if their CRT performances (both speed and accuracy) were at the 50th percentile or better. Participants completed 4 tests of 40 trials that had varying S–R compatibility. Two subscales of the modified Brunel Modified Scale (BRUMS) were administered prior to testing and immediately after a 40-trial test. Dependent variables included CRT, error scores, and BRUMS survey data. Mixed-design analyses of variance (ANOVAs) indicated that monetary rewards did not affect movement initiation, response accuracy, or tension and confusion levels. However, strong S–R effects were found, based on CRT, error scores, and BRUMS data. These results are discussed with respect to the mechanisms of monetary rewards and S–R effects.

In general, intellectually gifted children perform better than non-gifted children across many domains. The present validation study investigated the speed with which intellectually gifted children process information. 184 children, ages 9 to 13 years old (91 gifted, M age = 10.9 yr., SD = 1.8; 93 non-gifted children, M age = 11.0 yr., SD = 1.7) were tested individually on three information processing tasks: an inspection time task, a choice reaction time task, an abstract matching task. Intellectually gifted children outperformed their non-gifted peers on all three tasks obtaining shorter reaction time and doing so with greater accuracy. The findings supported the validity of the information processing speed in identifying intellectually gifted children.

This study examined the size of the useful visual field in patients (9 men, 6 women) with schizophrenia. A choice reaction task was conducted, and performances at 2.5, 5, 7, 10, and 25° in both visual fields were measured. Three key findings were shown. First, patients had slower choice reaction times (choice RTs) than normal controls. Second, patients had slower choice RTs in the right visual field than in the left visual field. Third, patients and normal controls showed the same U-shaped choice RT pattern. The first and second findings were consistent with those of other studies. The third finding was a clear indication of the patients' performance in peripheral vision, and a comparison with normal controls suggested that there was no difference in the size of the useful visual field, at least within 25°.

Hypoxia continues to be a significant source of peril in military aviation. Over three dozen hypoxia-related incidents were reported in the past decade with three resulting in fatalities (Clark & Megown, 2005; Ostrander, 2008). Previous work has addressed loss of consciousness resulting from extreme levels of hypoxia (Carlyle, 1963); however, most mishaps are related to moderate hypoxia exposure. More work is required to establish the cognitive effects of moderate hypoxia and the time required, post-exposure, to fully recover. The present study examined the effect of a ten minute exposure to an air mixture equivalent to 20,000 ft on two-choice reaction time. Carryover effects were assessed over a ten minute recovery period. Hypoxia exposure resulted in significant delays in two-choice reaction time. Significant carry-over effects continued to be detected throughout the recovery period. This information is essential to military aviation, where high levels of cognitive performance are required after moderate hypoxia exposure.

This study examined the effects of contingent muscular tension on a choice reaction task, and especially, the effects various amounts of muscular tension have on the information processing of choice reaction time. The reactive movement task included a choice reaction task. Ten right-handed healthy men (ages 18 to 19 years) underwent trials with stimulus presentation probabilities of 50% and 20% on the muscular tension task and choice reaction tasks. The conditions for the muscular tension tasks were divided into seven different conditions: 0%, 10%, 20%, 30%, 40%, 50%, and 60% of maximum voluntary contraction. On these tasks, subjects performed isometric contraction of the biceps brachii. The choice reaction task was a rapid extension of the left or right knee as a choice reaction. Measures were choice reaction time, movement time, and total reaction time. Analysis indicated that shortening choice reaction time of the left and right feet was observed under 10% muscular tension of maximum strength. Muscular tension appreciably influenced information processing, including choice reaction time. Muscular tension did not affect movement time. Results are discussed with respect to previous research and the optimal muscular tension for best performance.

Three choice reaction time experiments documented a Simon-type congruence effect involving the numbers of stimuli and responses. In Experiment 1 the stimulus consisted of one or two high- or low-pitch tones, and participants were required to respond with one or two taps of a response key depending on stimulus pitch. Responses were faster when the number of tones matched the required number of response taps than when these numbers mismatched. Experiment 2 showed that a weaker version of this effect can also be obtained using visual stimuli, and Experiment 3 showed that the analogous effect can even be obtained, albeit very weakly, with bimodal stimuli. There was also evidence that the number of stimuli affected the rate of emitting the two-tap response. These results indicate that stimulus numerosity is processed automatically to the level at which it can affect the selection and possibly the execution of a varying number of responses.

It is common to think that threat categorisation tendencies (TCTs) should undermine a person's subjective well‐being. However, recent research has suggested that the hedonic impact of such tendencies varies considerably according to a person's traits. The present research seeks to extend such a perspective by considering potential interactions between TCTs and the trait of agreeableness. TCTs were measured through the use of choice reaction time tasks contrasting the threat and non‐threat categories. As expected, TCTs were not correlated with the trait of agreeableness, but interacted with this trait in predicting the dependent measures. Within three studies involving 184 undergraduates, TCTs were associated with the higher levels of approach‐related behaviour and positive emotion among disagreeable individuals, but lower levels of these same variables among agreeable individuals. The authors suggest that threat categorisation tendencies psychologically protect or burden the individual, depending on the levels of agreeableness. Copyright © 2005 John Wiley & Sons, Ltd.

The effects of communication medium and member familiarity on decision time, member satisfaction, and decision accuracy were explored. The study represents the first known attempt to examine the role of member familiarity on the study variables in face-to-face (FTF) and computer-mediated (CM) mediums. The results of 71 three-person groups revealed familiarity affected decision time and accuracy within the CM condition. For CM groups only, as member familiarity among group members increased, decision time decreased, and unexpectedly decision accuracy decreased. Another finding for CM group members was an indication that familiarity increased satisfaction with group process. Last, satisfaction with communication medium was only influenced by the communication medium (CM group members were less satisfied). It appears that familiarity plays a larger role in CM groups than in FTF groups. Implications are discussed.

The duration of the enhancement of choice reaction task efficiency by physical exercise at lactate threshold was studied. After healthy male students completed the exercise or nonexercise (control) period for 10 min., they performed a three-choice reaction task for 20 min. The mean heart rate during the choice reaction task after the exercise was higher than that after the control period ( p

Subjects observed a random-dot pattern moving uniformly in the vertical direction (vector V1). The motion vector abruptly changed to V2, both in speed and direction simultaneously. It was found that the time of simple reaction to such changes V1 → V2 can be described by a function of a single variable, | w( V1 — V2C) + (1 – w) V2N|, 0 < w < 0.5, where V2C and V2N are the components of V2 collinear with and normal to V1. The choice-reaction time for changes in direction that are accompanied by changes in speed can be described by a function solely of the absolute value of V2N. Unlike the simple-reaction time, the choice-reaction time was independent of the initial speed of motion. The processes that may be engaged in simple and choice reactions to motion are discussed.

We aimed to identify demographic, health, and biomarker correlates of reaction time performance and to determine whether biomarkers explained age differences in reaction time performance. The sample comprised three representative cohorts aged 20–24, 40–44, and 60–64 years, including a total of 7,485 participants. Reaction time measures of intraindividual variability and latency were used. The measure of intraindividual variability used was independent of mean reaction time. Older adults were more variable than younger adults in choice reaction time performance but not simple reaction time performance. The most important correlates of reaction time performance after gender and education were biological markers such as forced expiratory volume at one second, grip strength, and vision. Few measures of physical or mental health or lifestyle were associated with poorer performance on reaction time measures. Biomarkers explained the majority of age-related variance in simple reaction time and a large proportion of variance in choice reaction time. We conclude that for the ages studied, biomarkers are more important than health factors for explaining age differences in reaction time performance.

Three studies involving 257 undergraduates examined whether a simple choice reaction time task could predict daily experiences of affect. Individuals who were fast to make negative evaluations experienced more negative affect and more somatic symptoms and were less satisfied with their lives, compared with individuals who were slow to make negative evaluations. A fourth study, involving 89 undergraduates, indicated that performance on the task was relatively unaffected by transitory mood states. The results support the idea that categorization provides a useful perspective on personality functioning.

In two-choice tasks, the compatible mapping of left stimulus to left response and right stimulus to right response typically yields better performance than does the incompatible mapping. Nonetheless, when compatible and incompatible mappings are mixed within a block of trials, the spatial compatibility effect is eliminated. Two experiments evaluated whether the elimination of compatibility effects by mixing compatible and incompatible mappings is a general or specific phenomenon. Left–right physical locations, arrow directions, and location words were mapped to keypress responses in Experiment 1 and vocal responses in Experiment 2. With keypresses, mixing compatible and incompatible mappings eliminated the compatibility effect for physical locations and arrow directions, but enhanced it for words. With vocal responses, mixing significantly reduced the compatibility effect only for words. Overall, the mixing effects suggest that elimination or reduction of compatibility effects occurs primarily when the stimulus-response sets have both conceptual and perceptual similarity. This elimination may be due to suppression of a direct response-selection route, but to account for the full pattern of mixing effects it is also necessary to consider changes in an indirect response-selection route and the temporal activation properties of different stimulus-response sets.

Studies of combined expectancies have shown that spatial cueing effects are reduced on trials on which participants have to respond with an unexpected motor response. In the first two experiments the range of reduced expectancy effects is examined. Advance knowledge of the likely response was combined in a trial-by-trial procedure with modality cueing, object cueing, and task cueing. Effects of modality cueing were reduced on trials on which the target requested an unexpected response. However, effects of object cueing as well as effects of task cueing were unaffected by response cueing. Comparing experiments revealed that different types of cues were used in different experiments. To test the effect of type of cue on the interaction of expectancies the third experiment combined spatial cueing with response cueing. When integrated cues were used that cued the likely target location by an arrow and the likely response by an arrow too, spatial cueing effects were reduced on trials with unexpected responses. However, spatial cueing effects remained unaffected by response cueing when separated cues were used consisting in a word cueing the response and an arrow cueing target location. An account for the modulation of combined expectancies by the relation between cues is suggested in terms of the adjusted expectancy model.

Does one night of sleep deprivation alter processes of supervisory attention in general or only a specific subset of such processes? Twenty college-aged volunteers, half female, performed a choice reaction time task. A cue indicated that compatible (e.g., right button, right-pointing arrow) or incompatible (e.g., left button, right-pointing arrow) responses were to be given to a stimulus that followed 50 or 500 ms later. The paradigm assessed response inhibition, task-shifting skill, and task strategy—processes inherent in supervisory attention. Performance, along with heart rate, was assessed for 12 hr following normal sleep or a night of complete sleep deprivation. Sleep deprivation altered neither preparation for task shifting nor response inhibition. The ability to use preparatory bias to speed performance did decrease with sleep deprivation. Sleep deprivation appears to selectively affect this supervisory attention process, which is perceived as an active effort to cope with a challenging task.

Using various card-sorting tasks, this class experiment shows how choice reaction time increases with the number of bits processed in tasks having familiar stimuli and one-to-one stimulus-response compatibility. Students deal decks of cards during four timed exercises into a specific number of piles according to color (2 piles), suit (4 piles), etc., which represent a different level of uncertainty measured by bits of information processed. A second deal is conducted without regard to suit, color, etc. to determine and remove movement time from the total deal time. The relationship of the resulting reaction time and bits is shown in a graph of data generated in real time from the students' four class exercises. This demonstration can be used to introduce the concept of information processing, to explore what experimental factors could contribute to the resultant time, and to discuss real-life choice reaction time applications.

The purpose of the study was to examine the within-subject variability in heart rate, pedal rate, choice reaction time, and error rate during simultaneous tasks of cycling and reaction time. Students in physical education classes exercised a 10-min. submaximal cycloergometer test at a relative power output corresponding to 60% of their own maximal aerobic power, in a replication procedure. Concomitantly, the subjects performed a 2-choice reaction time task from Min. 3 of the exercise bout. No significant differences ( p>.05) were found between the individual means in the tests for the diverse parameters. The total intraindividual variability averaged 1.3% for heart rate, 2.2% for pedal rate, and 13.3% for choice reaction time. Because wide within-subject variability was observed (from 7.7 to 16.7%), the reliability of choice reaction time was low. These data suggest that it is necessary to quantify more accurately the intraindividual differences of reaction time measures for the interpretation of exercise-changes in cognitive functioning.

Studies on implicit sequence learning have employed the methodology of task dissociations to show that tasks of conscious memory fail to reveal knowledge expressed in performance measures of learning. One critical requirement of this methodology is that the conscious memory tests tap the same type of information that is expressed in performance measures. When a deterministic sequence is being repeated during practice, identification of the exact type of sequential information that is learned can be achieved by a trial-by-trial comparison between the practised sequence and a control sequence. In Experiment 1 we examine whether short-term sequential effects are present in choice response time tasks and may therefore contaminate this trial-by-trial comparison. In Experiment 2 we control for these effects and demonstrate how specification of the exact sub-parts of the sequence that are learned is necessary before testing for task dissociations. Our findings indicate a dissociation between a response time task and a free generation task. This dissociation, however, is obtained for selected sub-parts of the sequence and may be caused by the insensitivity of the free-generation task to low confidence knowledge.

The aim of this study was to examine a possible relation between the speed of information processing, as measured by simple and choice visual RT, and problem-solving, as measured by the Tower of Hanoi test. For 20 normal teenagers, performing all tests, significant correlations were found between choice RT and both measures of performance on the Tower of Hanoi, number of disk moves, and time taken to complete the task. Simple RT was correlated with Completion time but not with the number of moves, while the reverse pattern was discerned for decision time. Choice movement time was also associated with both measures, but simple movement time was not. These results are consistent with the hypothesis of a common neurobiological basis to information-processing speed and executive functions.

Dual-task performance was assessed in 140 adults during eyeblink classical conditioning (EBCC) and one of several secondary tasks (timed-interval tapping, recognition memory choice reaction time, video viewing) Four groups received paired-EBCC stimulus presentation and three groups received explicitly unpaired EBCC stimuli Although the subjects were not told about the conditioning task, they acquired conditioned responses (CRs) at normal levels Postsession interviews probed participants' awareness of EBCC stimulus contingencies and production of CRs Reported awareness of paired-EBCC stimulus contingencies and CR production was not related to actual EBCC performance Twenty-seven percent of the participants receiving explicitly unpaired stimuli reported a stimulus contingency when none existed The dissociation between awareness and performance provides additional support for the categorization of simple EBCC as a form of nondeclarative learning

We report an experiment testing the hypothesis that impulsive behavior reflects a deficit in the ability to inhibit prepotent responses Specifically, we examined whether impulsive people respond more slowly to signals to inhibit (stop signals) than non-impulsive people In this experiment, 136 undergraduate students completed an impulsivity questionnaire and then participated in a stop-signal experiment, in which they performed a choice reaction time (go) task and were asked to inhibit their responses to the go task when they heard a stop signal The delay between the go signal and the stop signal was determined by a tracking procedure designed to allow subjects to inhibit on 50% of the stop-signal trials Reaction time to the go signal did not vary with impulsivity, but estimated stop-signal reaction time was longer in more impulsive subjects, consistent with the hypothesis and consistent with results from populations with pathological problems with impulse control

This study investigated the effects of expertise and age on cognitive resources relevant to mental workload of pilots engaged in simulated aviation tasks. A secondary task workload assessment methodology was used, with a PC-based flying task as the primary task, and a Sternberg choice reaction time task as the secondary task. A mixed design using repeated measures was employed, with age and expertise as between-subjects factors and workload as the within-subjects factor. Pilots ranging in age from 21 to 79 years and 28 to 11,817 hours of flight time served as subjects. Of interest was whether expertise would mitigate the adverse effect of aging on pilots' mental workload handling ability as defined by two measures of secondary task performance: choice reaction time and accuracy. Results indicated that expertise did mitigate the effects of age regarding secondary task accuracy. Implications of results are discussed, and directions for future research are presented.

The power law of choice reaction time, first proposed by Kvålseth (1980), is further discussed. It is shown that the so-called Hick-Hyman law is a special case of the power law. It is suggested that a particular square-root case provides a most concise and adequate formula lor predicting reaction time when the number of equiprobable stimulus-response pairs ranges from 1 to 10. A potential theoretical explanation is briefly discussed.

The purpose of this study was to investigate whether raised core temperature due to gradually increased amounts of exercise affects concentration and speed of information processing. 20 paid men, separated into groups of high (>56 ml/kg/min.) and low fitness (2max), participated in two experimental conditions (exercise and control). Concentration was measured by the Random Number Generation test of attentional deployment given every 10 min. of cycling at workloads calculated as 40, 50, 60, 70, and 80% of individual VO2max values and 10 min. after exercise cessation (exhaustion). Speed of information processing was estimated by an eight-choice reaction time/ movement time task given before and after exercise and 15 min. after exercise cessation. Core temperature was recorded at the same time individuals were administered the psychological tests. Analyses indicated that core temperatures increased significantly as a function of exercise intensity for high and low fitness groups. Correlations among the psychophysiological factors indicated that increases in core temperature were not associated with mental functioning. However, at certain core temperatures, core temperature and average choice reaction time/movement time were associated with participants' fitness.

To examine the effects of increasing amounts of exercise on attention and speed of information processing 20 paid male subjects were separated into groups of high and low fitness according to their VO2max values. The experiment involved an attentional task (Random Number Generation) that was given after every 10 min. of cycling at work-load resistances calculated as 40%, 50%, 60%, 70%, and 80% of individual VO2max values. An eight-choice reaction time-movement time task was given before and after exercise as well as after a 15-min. recovery period. Individuals were tested within 10 min. after exercise cessation (exhaustion) for concentration and within 15 min. for choice reaction time and movement time to assess whether fitness differentially interacted with these variables. Split-plot factorial analyses of variance suggested that the CNS appeared capable of maintaining performance after 50 min. of exhaustive exercise compared to values obtained at the preexercise condition. A 15-min. recovery period significantly impaired MT but relatively highly fit individuals did not appear to perform the choice RT and concentration tasks better than individuals low in fitness.

Previous studies have used a sequence choice procedure to explore the cognitive representations of forthcoming response sequences. Subjects choose as quickly as possible between memorized sequences, and differences in the choice reaction time for a given sequence as a function of the other possible sequence are used to model the structures and processes underlying the choice. In 1993 Shidoji reported experiments to distinguish between two models of choice. One model assumes a hierarchical editing process. The other model assumes that choice. One model assumes a hierarchical editing process. The other model assumes that choice time depends only on the total number of responses in the sequences to be distinguished. Shidoji argued that his data supported both models. He also suggested boundary conditions for the applicability of each model. I argue that the hierarchical editor model can account successfully for Shidoji's results.

Evidence analysed based on reaction time has contributed to the development of cognitive models of human information processing. Essential to the consideration of possible variables to be controlled when designing experimental work on cognitively related issues are variables such as the subjects' age, sex, or education. Barely a handful of studies have ever taken eye colour seriously as a variable to be controlled when exploring cognitively related issues. Very few researchers have considered the possibility that a person's eye colour might influence reaction time. The question is whether eye colour should be taken seriously when designing experimental work in cognitive psychology. In this study we found significant differences in choice reaction time using the McCarthy and Donchin (1981) paradigm, the dark-eyed subjects being faster than the light-eyed. Implications of the findings are discussed.

Previous research (McCann, Foyle, & Johnston, 1993) has shown that in a simulated approach to a runway, performance of a choice reaction time task is faster when all relevant information is available on the HUD or in the world, compared to when information has to be acquired from both domains. The present experiment tested two attentional models of these results: attention switching and attention sharing. Removing differential motion cues from the display, so that both the HUD and the world were motionless, attenuated the domain effect. The attenuated difference reflected both slower responses on within-domain trials and faster responses on between-domain trials. We conclude that performance with Head-Up Displays is affected by both attention switching and the degree to which attention is shared between domains.

Recent studies have related long reaction times and various musculoskeletal complaints in different groups of adults. The aim here was to analyze reaction times with reference to musculoskeletal complaints in adolescent athletes and controls. Simple reaction time and choice reaction time were measured, and inquiries made about various musculoskeletal injuries of 119 subjects aged 11 to 14 years. Gender, age, maturational age, body composition, and participation in sports were included in the analyses as subject-related factors affecting reaction times. Prolonged simple reaction time was related to low-back and lower extremity complaints in a two-way analysis of variance. The finding agreed with data of previous studies suggesting that slow psychomotor speed of reaction is associated with the outcome of musculoskeletal injuries.

The orienting of attention in space has not been considered in the tactile domain. This issue is examined using a modified version of a visual paradigm initially adopted by Posner, Snyder, and Davidson (1980), which manipulates the probability of a stimulus occurring at different spatial locations. Slower RTs at an unexpected stimulus location are thought to reflect the time required to shift attention from the expected to the unexpected location. In two experiments involving vibrotactile choice RT between left and right hands, the two hands were either crossed or uncrossed, and the hands were held both on the left side of the body, both on the right, or one on either side of the midline. There was no evidence to suggest that spatial location (left or right) affected the orienting of attention in the tactual modality. As predicted, RTs were slower when the arms were crossed compared with uncrossed, though this effect was smaller for the expected trials. A coding conflict hypothesis may explain both these findings, but the smaller effect in the expected trials may also reflect attentional factors. Both the relative and absolute location of the hands affected the magnitude of the crossed-arm effect and indicated that attention may play a role in the perceptual division of space into left and right sides. Possible reasons for hand or hemispace asymmetries in different simple and choice RT paradigms were discussed.

The aim of this study was to identify factors that might affect reaction-time (RT) testing and interpretation. Simple reaction time and choice reaction time were measured in a cohort of 893 white young men. Age, body size, color vision, and intelligence (IQ) were analyzed as subject-related factors. Effects of time of day of test and different examiners were analyzed in relation to testing facilities. All factors were statistically correlated to RTs; however, the relationships between age and RTs and between height and RTs were noticeably weak and apparently insignificant in practice. A defect in color vision was notably associated with slow choice RT and with mistakes on the test. As the choice was coded by color in the choice RT test, the result was expected. Low IQs were significantly related with slow RTs. Slow RTs have been correlated with low-grade IQs in previous studies also. Lower grades and greater variation in RTs were recorded just before meals or if testing was done outside the daily testing schedule. The examiner supervising the RT testing significantly affected the results. It was concluded that the introduction for tests should be given impersonally using a tape recorder or comparable equipment.

This research sought to determine the impact of arousal/activation, sex/gender, stimulus quality, practice, and task type on age-related slowing, as measured by reaction time, with analysis of RT distribution characteristics. Forty-four male and female subjects participated in the experiment: 28 young and 16 elderly. Subjects performed four-choice visual reaction tasks while seated and standing (postural stimulation of the central nervous system), with intersession practice and a complete replication of the study on a second day. Visual stimuli were presented as variable choice reaction time (VCRT) and serial choice reaction time (SCRT) tasks, i.e., in intact and degraded forms at varying response stimulus intervals (RSIs) and at a fixed response stimulus interval (RSI = 0), respectively. Data were analyzed by central tendency as well as variance, skewness, and unusually fast or slow responses. In addition to expected age-related slowing, results showed increased variance in elderly RT distributions, an overall shift in elderly versus young RT distributions, and a task dependent change in the shape of elderly RT distributions. For the fixed RSI task, which required sustained continuous performance; it was concluded that elderly subjects had a more difficult time than young subjects transitioning from the previous response to the current stimulus. For the variable RSI task, it was concluded that elderly subjects were more likely than young subjects to be caught “off guard”, unprepared to respond. Standing (increased arousal) decreased the likelihood that elderly subjects would be unprepared to respond thereby reducing speed difference by age. This investigation suggests that several mechanisms interact to cause not only a shift in elderly versus young RT distributions, but also changes in skewness and/or unusually slow responses.

The hypothesis that reaction times are positively associated with intelligence was tested on 479 9-yr.-old Chinese Hong Kong children. Intelligence was measured by the Standard Progressive Matrices, and 12 reaction time parameters were obtained to give measures of movement times, reaction times proper (decision times), differentiated into simple and complex reaction times, and their variabilities. Factor analysis of the reaction time tasks indicated the presence of a general reaction time factor and three component factors identifiable as movement times, reaction times proper, and variabilities. All three components showed statistically significant associations with intelligence of approximately equal magnitudes.

The primary aim of this study was to examine the effects of exercise intensity and duration on choice reaction time with a secondary aim to examine the influence of aerobic fitness on choice reaction time. Fifteen college-aged men enrolled in a physical fitness activity course participated. We observed a cubic trend ( r =.99) across exercise intensity that ranged from unloaded cycling to 90% of physical working capacity (PWC). However, no significant differences were noted across intensity (medium effect size) or duration (small effect size). The fastest choice reaction time occurred at 75% of PWC, which was near the ventilatory threshold (72.6% of VO2max). Aerobic fitness was average for college-aged men (39.3 ml/kg/min.) and was poorly correlated with choice reaction time across exercise intensity. Further research is needed to compare choice reaction time in high to low fitness groups across exercise intensity.

This study compared right-hand and left-hand two-choice CRT responses of college students to both the simplest chronoscope (a falling meterstick) and to a digital-readout multi-choice reaction timer (machine). Tests of ipsilateral differences showed significant differences in CRT between the meterstick and the machine methods for both right and left hands. There were no significant contralateral differences in CRT with either the meterstick or machine methods. Combined total scores showed that there were significant differences in CRT responses obtained by meterstick versus machine, whereas there were no differences in CRT responses for all right-hand responses versus all left-hand responses. Results suggest that perhaps the workings of two different reaction time systems may account for the robustness of differences between CRT's obtained by meterstick versus machine.

Choice Reaction Time involves at least two components of response latency, Decision Time and Movement Time. Studies usually report values for these two components averaged over a definite number of trials. The aims of this study were to investigate the pattern of behaviour of the two components across the trials and the effect of repeating the experimental procedure two weeks later. 16 control subjects were given two sessions of 50 trials each. In Session 1 (D.0), the two components behave quite differently across the trials; there was no significant change in decision time, but a significant reduction in movement time occurred. Decision and movement time show no relationship. In Session 2 (D.15), a different pattern was found; movement time was still significantly reduced across trials but there was also a significant increase in decision time so the two components exhibit a negative relationship. Comparison of values from Sessions 1 and 2 shows an effect is found only on the first 10 trials for both components, the values of decision and movement times being smaller in Session 2 than Session 1.

The information processing models used in the analysis of choice-reaction-time tasks are limited in their applicability to real detection tasks because the models are task dependent. The linear relationships between time and information processed in one task have not been extended to detection tasks in general. This paper examines a model for making the information processing models more general. Parameters relating to detection tasks are divided into two categories; those that influence the intercept (basic detection time) and those that influence the slope (information processing rate). Variables chosen for investigation were target size, target location certainty, distracting visual images, and average information content in the stimulus. Results indicated that target size, location certainty, and distracting images definitely affect “basic detection time.” It was also indicated that information-processing time, established by information content, was not greatly affected by those variables. An exception occurs with high levels of distracting images (clutter) which adds significant search time to a task.

Equipment and methodology for determining the effects of toxic substances on pilot performance were evaluated using ethyl alcohol as a reference substance, since its effects on flying performance in a flight simulator are well known. Four levels of ethyl alcohol were administered to eight instrument trained pilots in a Latin Square within subjects design. Significant performance decrements were found on instrument holding pattern, Instrument Landing System (ILS) approach, and Sternberg's choice reaction time tasks.

It is known that alcohol increases the time taken to identify signals and to make responses to them, but it is not known whether it also slows the rate of preparation for such events. These two performance parameters are not necessarily related, as age affects the former but not the latter. Twenty subjects participated in a 4-choice reaction time experiment in which they received no alcohol (NA) in the first session and either no alcohol (10 subjects) or 0.8 ml alcohol (A) per kg body weight (10 subjects) in the second session. In each session there were 300 practice trials, followed by 400 experimental trials at each one of five Response–Stimulus Intervals (RSI: 50, 100, 200, 400, and 800 msec). There was a significant effect of alcohol such that the reduction in response time from the first to the second session was 39 msec larger for the NA/NA group than for the NA/A group. Response time decreased significantly with increasing RSI, but there was no interaction between the effect of alcohol and RSI. Thus, alcohol slows the processing of an event requiring a choice response; however, like age and individual differences, but unlike practice, alcohol has no effect on the rate of preparation for that event. In addition, an analysis of what happened before and after an error revealed that practice and increasing RSI produce real improvements in performance rather than shifts in the tradeoff between speed and accuracy, whereas alcohol produces a real impairment. It is concluded that the relationship between the rate of preparation for, and processing of, a stimulus is not simple, as one factor (practice) influences both rates, whereas other factors (alcohol, individual differences, and age) influence the rate of processing only.

In order to determine the extent to which color defective observers are able to recognize colors presented on a VDU, a choice reaction time experiment was carried out. The experiment determined the effect of advance training, stimulus size and simultaneous color contrast on the performance of subjects, segregated into groups according to the nature of their color vision defect. Analysis of the data shows that type of color vision defect and the simultaneous color contrast influence the number of errors made by the subjects. Suggestions for future experiments and for the possible improvement of performance are given.

The purpose of this experiment was to test several explanations that have been given to account for what has been termed the Psychological Refractory Period effect. Specifically the question addressed was what effect does varying the complexity and uncertainty of stimulus-response pairs have upon the subsequent reaction time. The experiment employed a within-subject Latin square design in which 12 undergraduates completed four test conditions on separate days. The task was to respond to a visual stimulus (maximum of 4 possible lights) by depressing a telegraph key with the index or middle fingers of either the right or left hands (maximum of 4 possible responses). It was possible to produce four conditions. Condition 1-1 (usual PRP paradigm), 1-2 (simple reaction time followed by a choice reaction time), 2-1 (choice RT followed by simple RT), and 2-2 (choice RT followed by choice RT). In addition, 36% of all trials were uninformed catch trials, i.e., either S1 and/or S2 did not occur when the subject was expecting it to occur. The subjects completed 50 single-choice control reaction-time trials before each condition. The interstimulus interval in all conditions for both experiments varied randomly among 100, 200, 300, and 400 msec. There was no statistical support for the claim that increasing the number of choices in S2-R2 will lengthen RT1. These results are discussed in terms of McLeod's (1977) parallel-processing model.

The primary mission of the Air Force Aerospace Medical Research Laboratory, Systems Research Branch (AMRL/HEB), is to develop quantitative techniques, methods and models of operator performance and man/machine systems to specify system design criteria and effectiveness. The major thrust of this development has been through the use of the Human Engineering Systems Simulator (HESS)--composed of an IBM 370 (Model 155) computer with attached IBM 2250 graphic display units and extensive software developed by AMRL and the IBM Corporation.

This paper presents research conducted by the authors and others investigating the interaction of a variety of variables which are presumed to affect reaction time in hopes of obtaining much needed information on factors influencing age effects on attention and information processing. Reported is progress to date on an experiment which shows that the effects of age on central nervous system speed, as measured by visual choice reaction time, depends on many factors, including the gender, neural activation level, and skill of the subject as well as the stimulus quality and type of reaction task employed.

A location task, in which a worker must locate a point in space given information on its position, has much in common with a Choice Reaction Time (CRT) task. One particular task, wiring of electronic components, was studied by measuring location time as a function of total information per stimulus. A linear relationship was found, confirming Hicks Law, but systematic deviations from the line were noted. Further analysis showed differential rates of information processing and suggested a two-stage strategy. The first stage corresponded to the usual binary classification in CRT studies, while the second had similarities to an exhaustive serial search.