Human Reaction Time Research Articles

Constraints imposed on taste physiology by human taste reaction time data

The speed with which an organism responds to stimulus events is reaction time (RT): the minimum time interval between stimulus arrival at a receptor organ, and an overt response by the organism. This time interval specifies maximum duration of all processes necessary for the RT sequence. Responses to any change in taste have RT less than 1 sec for suprathreshold concentrations. Therefore, constituent events at taste receptors, in the central nervous system (CNS), and at the response organ, must have sufficient durations less than 1 sec (Constraint 1). Taste stimulus durations of 50 msec, and therefore taste receptor events of approximately 50 msec, are sufficient for these responses (Constraint 2), as well as for taste quality identification responses (Constraint 3). Taste receptor latencies, neural conduction times, and RT response organ events are even briefer. Thus, 60% to 90% of human taste RT is CNS events. Taste receptor events remain crutial, but CNS processing is important, and apparently time limiting, in all human taste judgments.

Perceptual information for batting can be extracted throughout a ball's trajectory.

Studies of batters' eye movements have demonstrated that batters do not (or cannot) maintain fixation on the ball throughout its trajectory. In addition, the velocity of a pitched ball, together with the limitations of human reaction time, seems to imply that only the first portions of the ball's trajectory provide information to batters. We prevented nine experienced fast pitch softball players from viewing the ball during the first, middle, or last third of its trajectory and found that seeing the first third of the ball's trajectory is not as critical as had been thought: batters are very good at making do with whichever two-thirds of the ball's trajectory is visible. The results demonstrate the importance of peripheral vision and indicate that batters can extract perceptual information for batting throughout the flight of the ball.

Facilitative and suppressive effects of punishment on the reaction time in humans under various conditions.

The effects of brief shock as the punishing stimulus during a simple or choice reaction time task (SRT or CRT) and the change in skin resistance during a key-pressing response were investigated under various conditions. A slowing of the SRT and CRT occurred similarly during the shock phase under both the response-contingent and response-independent shock conditions. After the elimination of shock, the suppressive effect of contingent shock was still observed but an effect for independent shock disappeared at once (experiment 1). A facilitation of a punished response could be demonstrated under the discriminative punishment condition in which the unpunished response was available, although the CRT for the punished response showed an eventual slowdown as punishment trials progressed. By contrast, the unpunished response showed a slowdown of the CRT throughout the punishment period. Consequently, both the CRTs for the punished and the unpunished responses indicated similarly high values in the late stage of punishment. The removal of shock brought about a completely different trend for both types of responses; a suppression of the punished response was maintained but the CRT for the unpunished response recovered to the baseline level immediately (experiment 2). These results were explained by two distinct effects of punishment: a nonspecific emotionalizing effect arising from the punishment situation itself and a specific reaction to the punished response stemming from response-shock contingencies. The former effect could be easily affected by giving a pseudo-instruction in advance (experiments 3 and 4). Changes in skin resistance were mainly dependent upon the response-shock contingencies, but they did not parallel changes in the CRT for the punished response. The autonomic response rose and diminished prior to changes in overt behavior.

Taste flashes: reaction times, intensity, and quality.

Human simple reaction times and magnitude estimates of taste intensity increased as the duration of 500-millimolar sodium chloride or 2-millimolar saccharin sodium pulses lengthened from 100 to 1000 milliseconds. Responses to "What was the taste?" ranged from 94 to 100 percent "sweet" for saccharin and 68 to 83 percent "salty" for salt across all pulse durations when both substances were randomized with water pulses.

Human reaction time: Toward a general theory.

Human reaction time: Toward a general theory.

Human reaction time: Toward a general theory.

Human reaction time: Toward a general theory.

Effects of chlorpromazine on escape and avoidance responses: A closer look

While a wealth of evidence has implicated the nigrostriatal dopamine system in the initiation of movement, most or all of these movements have been in a conditioned avoidance framework, and on the order of 3–14 seconds in latency. It is proposed tere that an elucidation of dopaminergic involvement initiation requires a behavioral paradigm wherein experimental animals must rapidly and voluntarily respond to a stimulus to move (i.e., in less than 300 msec, paralleling human reaction time). Such a paradigm was developed and implemented in a re-analysis of earlier reports of chlorpromazine (CPZ) effects on escape from and avoidance of electric shock. Catecholaminergic or dopaminergic receptor blocking by CPZ resulted in clear impairment of the ability to initiate rapid avoidance movements, but in contrast to earlier work, some impairment of escape responses was also seen. Results are seen as further support for dopaminergic involvement in the initiation of voluntary movement.

Effects of a peptide analog on event-related potential components, heart rate and reaction time in humans

Effects of a peptide analog on event-related potential components, heart rate and reaction time in humans

Effects of Aircraft Motion on Passengers' Comfort Ratings and Response Times

Comfort ratings and response times for changes in the experienced level of comfort were examined in 20 subjects using the NASA Flight Research Center's Jetstar aircraft modified to carry the GPAS system (General Purpose Airborne Simulator). Data were obtained for each of the subjects during two runs of 10 1-min. flight segments. In general, as the magnitude of aircraft motion increased in either the vertical or transverse (lateral) directions, there was an increase in feelings of discomfort and a decrease in response times to those changes. These results suggest parallels between the large body of laboratory data on human reaction time and that collected in this field study on response times to changes in ride comfort.

Effect of stimulus presentation duration on gustatory reaction time

Human simple reaction time to 3 sec and brief (200 and 400 msec) flow durations of aqueous 500 mM NaCl to the anterior dorsal tongue surface was measured for fifteen participants. Overall reaction time was 403 ± 30 msec (median ± 99% standard error of the median confidence interval). No statistically significant difference in reaction time as a function of flow duration was found. We conclude that 200 msec is ⩾ minimum human taste input time. This suggests that the phasic components of the gustatory neural response are sufficient for some human taste judgments.

Simple apparatus for generating reaction time histograms

Human reaction times (RT) to sensory stimuli show variations that cannot be explained by peripheral or central neural processes. The statistical distribution of RT's for a given stimulus and differences in RT distributions for different stimuli seem to have received little attention. This report describes a simple apparatus for generating RT histograms while a subject responds to various stimuli. The system has been found useful not only for the on-line generation of RT histograms with light and sound stimuli but also for studying simultaneously the time course of cortical potentials evoked by these stimuli.

Naso-temporal differences in human reaction time in the peripheral visual field

Visual reaction times (RTs) were measured using two trained, right-handed subjects with normal vision. A target was presented to 11 retinal loci: fovea; and 10°, 20°, 40° and 50° on both the nasal and the temporal sides of the fovea along the horizontal meridian of the right eye. Stimulus luminance was fixed at 8.50 cd/m 2. RT measured on the basis of a right-hand response increased as a function of retinal eccentricity from the fovea. Moreover, RT to stimulation on the nasal side of the retina was significantly faster than RT to stimulation on the temporal side at any corresponding retinal locations. Furthermore, the data suggested that the mean naso-temporal difference in RT increased as a function of the distance from the fovea. It was hypothesized that inter-hemispheric transmission time may be a major determinant of naso-temporal differences in RT.

Effects of marijuana on human reaction time and motor control.

In this research were analyzed the effects of marijuana on human reaction time and on performance for motor responses involving both linear and rotary serial arm movements aimed at a target. A total of six experienced marijuana users served as subjects and three drug conditions (dose levels) were used, i.e., 0, 6.5, and 19.5-26.0 mg delta9-THC. The results showed that (a) (simple and complex) reaction time was not significantly affected by marijuana or by the interaction between drug conditions and the amount of information transmitted during the task, (b) linear movement time was significantly reduced after smoking marijuana, while rotary movement time was not significantly affected, (c) interaction between drug conditions and task complexity was insignificant in the case of both linear and rotary movements, and (d) error rates for the two types of motor movements increased significantly and especially for linear movements as the dose level increased.

Visual search in the pigeon: hunt and peck method.

Pigeons pecked at small forms displayed on an oscilloscope screen under computer control. The birds were required to find a small o amid varying numbers of x forms. A photocell glued to the bird's beak provided a signal to the computer when the beak approached a form, and the computer recorded the time and target of the response. As in some similar studies with human subjects, erros and reaction times increased with number of x forms displayed. The method appears promising for further studies of search and of other processes related to perception and information-processing in birds.

Reaction time as a function of peripheral retinal locus around fovea: effect of stimulus size.

Using targets of four sizes between 18' and 116' at a fixed luminance of 5.8 cd/m2, human visual reaction times (RT) were measured on a circle at 30 degrees eccentric to the fovea. A foveal and 12 peripheral retinal loci were explored, covering the range between 0 degrees and 330 degrees in steps of 30 degrees units on a circle about the fovea. RT decreased significantly by the stimulation to the quadrant retinal loci between nasal and superior side. RT decreased as a function of increasing target size and the amount of decrement was relatively larger in the periphery than in the fovea.

The electroencephalogram in the prediction of human reaction time during growth and development

Characteristics of the distributions of electroencephalographic (EEG) half waves recorded in children during performance of a simple auditory reaction time (RT) task were investigated. The purpose was to determine the extent to which difference in these distributions could account for children's slow RT. The durations of a sample of 760 EEG half waves in each of a group of 41 healthy children aged 5–17 yr were measured and distributed into an interval histogram, and the first four central moments of the 41 distributions were computed. All four of the moments — which measure the central tendency, dispersion, skewness and kurtosis of the distributions — proved to be significantly correlated ( p < 0.01) with RT. The multiple correlation ( R) between RT and the four moments was equal to 0.68 and was statistically significant. R was unchanged when only the measures of dispersion, skewness and kurtosis were used as predictor variables, suggesting that the predictive value of the central tendency is low. The predictive capability of a multiple regression equation based on these three predictor variables was tested in an independent group of 42 children also aged 5–17 yr. EEGs and RTs were recorded and this group was treated in exactly the same way as the other group. The correlation between these children's average RTs and their RTs as estimated from the other group's regression equation was 0.53. These findings suggested that knowing the degree of dispersion, skewness and kurtosis of the children's EEG distributions reduces from chance by about 28 % the error of predicting their RTs.

Ethanol induced slowing of human reaction time and speed of voluntary movement.

This study tested the hypothesis that a CNS depressant (ethanol) would affect self-initiated psychomotor movement speed as much as the speed of an homologous movement made in response to an external stimulus. Four normal Ss (three male, one female, aged between 33-45 years) provided well-practiced measures of reaction time and a simple homologous traverse movement (a) in response to a signal from the E and (b) initiated at the S's own discretion. Performance by each S under ethanol conditions (B. A. L. .22%) was compared with his own baseline (pre- and postdrug) scores. Traverse originated by the S was consistently faster in the nondrug condition. Under peak-ethanol, both forms of traverse were slowed significantly in all Ss. Speed reductions were similar but consistently greater for self-initiated movement. A single S who repeated the experimental sequence under a minimally effective dosage (B. A. L. .08%) showed no important reduction in reactive movement speed, but was slowed significantly in self-initiated traverse measured concomitantly. The selective sensitivity of self-initiated movement to ethanol provides added evidence that a higher level of neural organization underlies control of human voluntary action.

Human reaction time variability changes from low intensity 3-hz and 10-hz electric fields: interactions with stimulus pattern, sex and field intensity.

Eighty simple reaction times (RT) to the onset of a light stimulus during 40 min of 3 successive 10-min exposures to 3-Hz and 10-Hz electric field were measured for each of 70 human male and female subjects exposed to either 3 0 V/m, 0.3 V/m or sham field conditions. The electric fields were applied horizontally across the upper half of the subject who was seated in a Faraday cage during the experiment. Two methods of presenting the RT-stimulus (light onset) were used which incorporated rest or no rest periods. No significant differences in mean RT were noted between sexes, intensities or frequency changes. Significant sex, intensity and frequency interactions were found in the amount of RT variability as measured by the RT standard deviation of 20 trial blocks. However, the magnitude of the effects was quite small and may be of little practical importance.

A Comparison of Speech Sound Discrimination in Man and Monkey

Enhanced discrimination between speech sounds across phoneme boundaries relative to discrimination within phoneme categories based on identification defines categorical perception. The present experiment compared man and Old World monkey on speech sound discrimination and particularly on the ability to perceive categorically. Difference thresholds for three humans and four monkeys were determined on a synthetic speech sound continuum from “BA” to “DA.” Humans were instructed and monkeys conditioned with food reinforcement to indicate a stimulus change from a repetitive “BA” in a direction towards the other phoneme “DA,” or, from “DA” towards “BA.” In addition to percent correct discrimination data, reaction times to stimulus change were recorded. Thresholds, defined as 50% correct discrimination between speech sounds, were typically smaller for humans than for monkeys and tended to occur intraphonemically for humans, but at phoneme boundaries for monkeys. Human reaction times, however, were longer near threshold than were those for monkeys, presumably due to increased time required for discriminating within a phoneme category. In this experiment, therefore, the reaction time data provided better evidence for categorical perception in humans than did percent correct discrimination data. [Research supported by grants from NIH and University of Michigan.]

Reaction Time as a Measure of Threshold and Suprathreshold Hearing. I. Normal Man and Monkey

Reaction time to auditory stimuli has been suggested as a measure of loudness in nonverbal animals [Stebbins, J. Exp. Anal. Behav. 9, 135 (1966)]. The reaction time task can also be used to measure threshold. We have compared the relationship of this measure to other psychophysical measures of loudness and threhsold hearing in man, and have compared hearing in man and monkey under similar experimental conditions. Absolute sensitivity functions derived from human reaction time data closely matched clinical threshold measures and were an average of 5 dB above thresholds measured by a forced-choice method. Human equal-reaction time contours matched closely equal-loudness contours derived in the same subject by loudness matching. The human and monkey equal-reaction time contours are similar throughout the overlapping hearing range of the two species. The results of this study support the suggestion that response latency can be used as a measure of threshold hearing and loudness and have application to the study of mechanisms underlying hearing in the animal model. [Work supported by PHS Grants NS 08181, RR 00166, NS 50637, and NS 05082.]