Human Reaction Time Research Articles

MINIMAL TRAFFIC MODEL WITH SAFE DRIVING CONDITIONS

We have developed a new computational traffic model in which security aspects are fundamental. In this paper we show that this model reproduces many known empirical aspects of vehicular traffic such as the three states of traffic flow and the backward speed of the downstream front of a traffic jam (C), without the aid of adjustable parameters. The model is studied for both open and closed single lane traffic systems. Also, we were able to analytically compute the value of C as 15.37 km/h from a relation that only includes the human reaction time, the mean vehicle length and the effective friction coefficient during the braking process of a vehicle as its main components.

聴覚先行手がかり刺激による注意喚起が人間操作者の反応時間に与える影響

聴覚先行手がかり刺激による注意喚起が人間操作者の反応時間に与える影響

A tutorial for analyzing human reaction times: How to filter data, manage missing values, and choose a statistical model

ABSTRACTThis tutorial for the statistical processing of reaction times collected through a repeated-measure design is addressed to researchers in psychology. It aims at making explicit some important methodological issues, at orienting researchers to the existing solutions, and at providing them some evaluation tools for choosing the most robust and precise way to analyze their data. The methodological issues we tackle concern data filtering, missing values management, and statistical modeling (F1, F2, F1 + F2, quasi-F, mixed-effects models with hierarchical, or with crossed factors). For each issue, references and remedy suggestions are given. In addition, modeling techniques are compared on real data and a benchmark is given for estimating the precision and robustness of each technique.

Exploring lexical co-occurrence space using HiDEx

Hyperspace analog to language (HAL) is a high-dimensional model of semantic space that uses the global co-occurrence frequency of words in a large corpus of text as the basis for a representation of semantic memory. In the original HAL model, many parameters were set without any a priori rationale. We have created and publicly released a computer application, the High Dimensional Explorer (HiDEx), that makes it possible to systematically alter the values of these parameters to examine their effect on the co-occurrence matrix that instantiates the model. We took an empirical approach to understanding the influence of the parameters on the measures produced by the models, looking at how well matrices derived with different parameters could predict human reaction times in lexical decision and semantic decision tasks. New parameter sets give us measures of semantic density that improve the model's ability to predict behavioral measures. Implications for such models are discussed.

Alteration of human motor response in relation to endogenous and exogenous factors. Part 1: Simple human reaction time and body mass index

Alteration of human motor response in relation to endogenous and exogenous factors. Part 1: Simple human reaction time and body mass index

On the search for an appropriate metric for reaction time to suprathreshold increments and decrements

Weber contrast, ΔL/L, is a widely used contrast metric for aperiodic stimuli. Zele, Cao & Pokorny [Zele, A. J., Cao, D., & Pokorny, J. (2007). Threshold units: A correct metric for reaction time? Vision Research, 47, 608–611] found that neither Weber contrast nor its transform to detection-threshold units equates human reaction times in response to luminance increments and decrements under selective rod stimulation. Here we show that their rod reaction times are equated when plotted against the spatial luminance ratio between the stimulus and its background (Lmax/Lmin, the larger and smaller of background and stimulus luminances). Similarly, reaction times to parafoveal S-cone selective increments and decrements from our previous studies [Murzac, A. (2004). A comparative study of the temporal characteristics of processing of S-cone incremental and decremental signals. PhD thesis, New Bulgarian University, Sofia, Murzac, A., & Vassilev, A. (2004). Reaction time to S-cone increments and decrements. In: 7th European conference on visual perception, Budapest, August 22–26. Perception, 33, 180 (Abstract).], are better described by the spatial luminance ratio than by Weber contrast. We assume that the type of stimulus detection by temporal (successive) luminance discrimination, by spatial (simultaneous) luminance discrimination or by both [Sperling, G., & Sondhi, M. M. (1968). Model for visual luminance discrimination and flicker detection. Journal of the Optical Society of America, 58, 1133–1145.] determines the appropriateness of one or other contrast metric for reaction time.

1∕fαnoise in reaction times: A proposed model based on Piéron’s law and information processing

Piéron's law relates human reaction times to the intensity of a sensory stimulus by a power function. The neural processes responsible for this nonlinear behavior are not understood. A simple neural model based on the Brownian motion of spikes and information theory is presented. The model shows that Piéron's law is a transformation function in time. The shape of Piéron's law is invariant and scales into the intensity-response function of single neurons in a fractal-like process. The model also shows that Piéron's law gives rise to 1/falpha noise together with a high-frequency thermal noise limit. It is proposed that the biophysical origin of reaction time variability is related to a form of noise-induced synchronization in weakly coupled neurons. The implications in visual-motor transduction are discussed.

NEW DEFINITIONS OF KINETIC VISUAL ACUITY AND KINETIC VISUAL FIELD AND THEIR AGING EFFECTS

Senior citizens in Japan who are renewing their driver's licenses must attend a class and undergo a kinetic visual acuity test to determine their driving aptitude. In this study, the authors identify problems with traditional methods used for defining kinetic visual acuity and kinetic visual fields. They propose new definitions that measure simple reaction times of both young and elderly drivers, taking into account individual differences in human simple reaction times. The authors also investigate the aging effects of kinetic visual acuity and kinetic visual field properties.

View-invariant object category learning, recognition, and search: How spatial and object attention are coordinated using surface-based attentional shrouds

How does the brain learn to recognize an object from multiple viewpoints while scanning a scene with eye movements? How does the brain avoid the problem of erroneously classifying parts of different objects together? How are attention and eye movements intelligently coordinated to facilitate object learning? A neural model provides a unified mechanistic explanation of how spatial and object attention work together to search a scene and learn what is in it. The ARTSCAN model predicts how an object’s surface representation generates a form-fitting distribution of spatial attention, or “attentional shroud”. All surface representations dynamically compete for spatial attention to form a shroud. The winning shroud persists during active scanning of the object. The shroud maintains sustained activity of an emerging view-invariant category representation while multiple view-specific category representations are learned and are linked through associative learning to the view-invariant object category. The shroud also helps to restrict scanning eye movements to salient features on the attended object. Object attention plays a role in controlling and stabilizing the learning of view-specific object categories. Spatial attention hereby coordinates the deployment of object attention during object category learning. Shroud collapse releases a reset signal that inhibits the active view-invariant category in the What cortical processing stream. Then a new shroud, corresponding to a different object, forms in the Where cortical processing stream, and search using attention shifts and eye movements continues to learn new objects throughout a scene. The model mechanistically clarifies basic properties of attention shifts (engage, move, disengage) and inhibition of return. It simulates human reaction time data about object-based spatial attention shifts, and learns with 98.1% accuracy and a compression of 430 on a letter database whose letters vary in size, position, and orientation. The model provides a powerful framework for unifying many data about spatial and object attention, and their interactions during perception, cognition, and action.

An anti-Hick's effect in monkey and human saccade reaction times

In order to execute movements to targets in the environment, we must first select a target in which to move, generally from an array of alternatives. Hick's Law states that reaction time (RT) increases as the number of response alternatives increases. Violations of this law, however, generally in the form of the absence of a relationship between response alternatives and RT have been reported in the literature. K. Kveraga, L. Boucher, and H. C. Hughes (2002), for example, found that saccades to visual targets violate Hick's Law. To examine this violation further, we measured saccade RTs in monkeys and humans and found that saccade RTs actually decreased as the number of potential target locations increased. We hypothesize that this arises because subjects must actively inhibit premature saccades, and that the required inhibition increases as the certainty of a movement to a particular location increases. With increased inhibition, saccade onset is delayed, resulting in an anti-Hick's effect.

No effect of an UMTS mobile phone‐like electromagnetic field of 1.97 GHz on human attention and reaction time

Several studies in the past reported influences of electromagnetic emissions of GSM phones on reaction time in humans. However, there are currently only a few studies available dealing with possible effects of the electromagnetic fields emitted by UMTS mobile phones. In our study, 40 healthy volunteers (20 female, 20 male), aged 26.0 years (range 21-30 years) underwent four different computer tests measuring reaction time and attention under three different UMTS mobile phone-like exposure conditions (two exposure levels plus sham exposure). Exposure of the subjects was accomplished by small helical antennas operated close to the head and fed by a generic signal representing the emissions of a UMTS mobile phone under constant receiving conditions as well as under a condition of strongly varying transmit power. In the high exposure condition the resulting peak spatial average exposure of the test subjects in the cortex of the left temporal lobe of the brain was 0.63 W/kg (min. 0.25 W/kg, max. 1.49 W/kg) in terms of 1 g averaged SAR and 0.37 W/kg (min. 0.16 W/kg, max. 0.84 W/kg) in terms of 10 g averaged SAR, respectively. Low exposure condition was one-tenth of high exposure and sham was at least 50 dB below low exposure. Statistical analysis of the obtained test parameters showed that exposure to the generic UMTS signal had no statistically significant immediate effect on attention or reaction. Therefore, this study does not provide any evidence that exposure of UMTS mobiles interferes with attention under short-term exposure conditions.

Sequential behavior in the rat: role of skill and attention

The serial reaction time task (SRTT) is a well-established experimental tool to study cognitive and neural mechanisms of sequential performance in humans. We have recently developed a rodent version of the human serial reaction time task, in which rats have to respond to visual stimuli by nose-poking into one of four spatial locations in order to obtain food reward. In this task, rats display superior performance under sequential as compared to random conditions of stimulus presentation. Specifically, the subjects are able to profit from sequential regularities in terms of faster reaction times and higher response accuracy. Here, we studied the effects of violating a single stimulus in rats, which had been intensively trained under sequential conditions, and we asked whether these subjects, when confronted with sequence violations, still attend to the actual stimulus order (that is, show correct responses), or whether their behavior has become fully automated (leading to specific incorrect responses to violated stimulus positions). In two independent experiments using partly differing instrumental set-ups, we found that the responses to non-cued violations of single stimulus positions were mostly correct, that is, the animals were apparently attending to the stimuli. Nevertheless, these reaction times were slowed, which probably reflects cognitive resources necessary to respond correctly to the unexpected irregularities. When quantifying the minority of responses, which were incorrect, we found that most of them were directed to the position, where the stimulus would have appeared if the sequence had not been violated. These responses were faster than the correct ones (to the violated stimulus), which indicates that sequential responding had become partly automated. Together, our data show that both, attention and skill play a role for sequential performance in our SRT task, and that they can be dissected by quantification of specific response types. In future work, the neural correlates underlying these functional mechanisms will have to be addressed.

Simple and complex reaction time measurement: A preliminary evaluation of new approach and diagnostic tool

Investigations of reaction time have been employed in various medical specialties as well as psychology. Although numerous tools have been employed, a universal diagnostic tool has yet to be developed in meeting the requirements of all specialties. Therefore, based on the assumptions of the test theory, we developed a new diagnostic tool, a designed program, designated as Reactor. Subsequent to its implementation in Visual Basic for application and MS Access, Reactor was initially estimated in a group of students. Preliminary evaluation of the Reactor has revealed that it is an innovative and useful diagnostic tool in compliance with the physiological model of reaction time in humans.

The Visibility Map, a Constraint for an Active Visual Search by a Humanoid Robot

This paper presents a framework for a visual search behavior of a 3D object in a 3D environment performed by a HRP-2 humanoid robot. The object search falls in the field of sensor planning and is formulated as an optimization problem. The goal is to maximize the target detection probability while minimizing the energy/distance and time to achieve the task. This paper propose some natural constraints based on specificities of the humanoid robot and on the characteristics of the recognition system to reduce the dimension of the problem. It also guides the optimization by restricting the sensor configuration space to meet heavy time constraints on the behavior in order to have a reactive and near human like reaction time.

The serial reaction time task in the rat: Effects of D1 and D2 dopamine-receptor antagonists

Sequential behaviour, probably reflecting procedural learning, has intensively been investigated in humans and monkeys using so-called serial reaction time tasks (SRTT), where serial stimuli are either presented in a random or sequential fashion. Learning of sequences is typically inferred from faster reaction times to such sequences as compared to random blocks of stimuli. Work with such tasks has shown that sequential behaviour seems to be mediated by specific brain systems, including the basal ganglia and the neurotransmitter dopamine. We have recently developed a rat version of the human serial reaction time task, in which rats have to respond to visual stimuli in one of four spatial locations by nose-poking in order to obtain food reward under a fixed ratio schedule (FR13). Here, we used a test version where random and sequential condition phases (10 min each) were alternated within-sessions. In support of our previous work, we found that well-trained (i.e. skilled) rats display superior performance under sequential than random conditions, namely, faster reaction times and higher response accuracies. Furthermore, we investigated the effects of selective dopamine-receptor blockade, by systemically administering SKF 83566, a D1 antagonist (.05–.15 mg/kg), or raclopride, a D2 antagonist (.05–.20 mg/kg), in two separate experiments. Both antagonists impaired responding to the conditioned visual stimuli in a dose-related way, i.e. they decreased, or even blocked, nose-poke rates. In those rats, which kept responding, the speeding of reaction times during sequential conditions was no longer observed with the D1 antagonist, whereas the enhancements in accuracy were preserved, or even enhanced as compared to vehicle. The D2 antagonist also impaired instrumental behaviour, but did not alter sequence effects on accuracy or reaction times. In contrast to responses to the conditioned stimuli, reaction times to the unconditioned stimuli (food pellets) were not substantially affected by either drug. These results are discussed with respect to methodological factors, and the possible role of dopamine for instrumental behaviour, in general, and sequential behaviour, in specific.

Word frequency effects in high-dimensional co-occurrence models: A new approach

The HAL (hyperspace analog to language) model of lexical semantics uses'global word co-occurrence from a large corpus of text to calculate the distance between words in co-occurrence space. We have implemented a system called HiDEx (High Dimensional Explorer) that extends HAL in two ways: It removes unwanted influence of orthographic frequency from the measures of distance, and it finds the number of words within a certain distance of the word of interest (NCount, the number of neighbors). These two changes to the HAL model produce measures of word neighborhood density that are reliably predictive of human lexical decision reaction times.

Approaches to extrapolating animal toxicity data on organic solvents to public health

Synthesizing information about the acute neurotoxicity of organic solvents into predictive relationships between exposure and effect in humans is difficult because (1) data are usually derived from experimental animals whose sensitivity to the chemical relative to humans is unknown; (2) the specific endpoints measured in laboratory animals seldom translate into effects of concern in humans; and (3) the mode of action of the chemical is rarely understood. We sought to develop approaches to estimate the hazard and cost of exposure to organic solvents, focusing on the acute behavioral effects of toluene in rats and humans. Available published data include studies of shock avoidance behavior in rats and choice reaction time in humans. A meta-analysis of these data suggested that a 10% change in rat avoidance behavior occurs at a blood concentration of toluene 25 times higher than the concentration at which a 10% change in human choice reaction time occurs. In contrast, our in vitro studies of nicotinic acetylcholine receptors indicated that human and rat receptors do not differ in sensitivity to toluene. Analysis of other dose-response relationships for visual and cognitive functions in rats suggests that the apparent difference between rats and humans may be driven by the specific endpoints measured in the two species rather than by inherent differences in sensitivity to toluene. We also explored the hypothesis that dose-equivalence relationships may be used to compare the societal costs of two chemicals. For example, ethanol-induced changes in choice reaction time, for which societal costs are estimatable, may be used as a benchmark effect for estimating the monetary benefits of controlling exposure to organic solvents. This dose-equivalence method is applicable for solvents because this set of data fulfills three important assumptions about equivalence relationships based on a single effect: (1) a common dose metric (concentration of the chemical in the brain); (2) a common effect to provide a linking variable (choice reaction time); and (3) a common mode of action (interference with neuronal ion channel function).

The sensitivity of human event-related potentials and reaction time to mobile phone emitted electromagnetic fields

There is some evidence to suggest that exposure to mobile phones (MPs) can affect neural activity, particularly in response to auditory stimuli. The current investigation (n = 120) aimed to test recent findings in this area, namely that N100 amplitude and latency would decrease, and that P300 latency and reaction time (RT) would increase under active relative to sham exposure during an auditory task. Visual measures were also explored. A double blind, counterbalanced, crossover design was employed where subjects attended two sessions 1 week apart. In both sessions participants (1) performed auditory and visual oddball tasks while electroencephalogram (EEG) was recorded with a MP set to sham exposure mounted over the temporal region, and (2) performed the same tasks while the handset was set to active/sham. When active, the MP transmitted for 30 min at 895 MHz (average power 250 mW, pulse modulated at 217 Hz, average SAR 0.11 W/kg). Paired t-tests compared difference scores from the sham/sham session to those from the sham/active condition. The study was designed to detect differences of 1\4 of a standard deviation with a power of 0.80. There was no significant difference between exposure conditions for any auditory or visual event related potential (ERP) component or RT. As previous positive findings were not replicated, it was concluded that there is currently no evidence that acute MP exposure affects these indices of brain activity.

Optimal Decisions: From Neural Spikes, through Stochastic Differential Equations, to Behavior

There is increasing evidence from in vivo recordings in monkeys trained to respond to stimuli by making left- or rightward eye movements, that firing rates in certain groups of neurons in oculo-motor areas mimic drift-diffusion processes, rising to a (fixed) threshold prior to movement initiation. This supplements earlier observations of psychologists, that human reaction-time and error-rate data can be fitted by random walk and diffusion models, and has renewed interest in optimal decision-making ideas from information theory and statistical decision theory as a clue to neural mechanisms. We review results from decision theory and stochastic ordinary differential equations, and show how they may be extended and applied to derive explicit parameter dependencies in optimal performance that may be tested on human and animal subjects. We then briefly describe a biophysically-based model of a pool of neurons in locus coeruleus, a brainstem nucleus implicated in widespread norepinephrine release. This neurotransmitter can effect transient gain changes in cortical circuits of the type that the abstract drift-diffusion analysis requires. We also describe how optimal gain schedules can be computed in the presence of time-varying noisy signals. We argue that a rational account of how neural spikes give rise to simple behaviors is beginning to emerge.

Visual Information Processing in the Lion-Tailed Macaque (Macaca silenus): Mental Rotation or Rotational Invariance?

Mental rotation is a widely accepted concept indicating an image-like mental representation of visual information and an analogue mode of information processing in certain visuospatial tasks. In the task of discriminating between image and mirror-image of rotated figures, human reaction times increase with the angular disparity between the figures. In animals, tests of this kind yield inconsistent results. Pigeons were found to use a time-independent rotational invariance, possibly indicating a non-analogue information processing system that evolved in response to the horizontal plane of reference birds perceive during flight. Despite similar ecological demands concerning the visual reference plane, a sea lion was found to use mental rotation in similar tasks, but its processing speed while rotating three-dimensional stimuli seemed to depend on the axis of rotation in a different way than found for humans in similar tasks. If ecological demands influence the way information processing systems evolve, hominids might have secondarily lost the ability of rotational invariance while retreating from arboreal living and evolving an upright gait in which the vertical reference plane is more important. We therefore conducted mental rotation experiments with an arboreal living primate species, the lion-tailed macaque. Performing a two-alternative matching-to-sample procedure, the animal had to decide between rotated figures representing image and mirror-image of a previously shown upright sample. Although non-rotated stimuli were recognized faster than rotated ones, the animal’s mean reaction times did not clearly increase with the angle of rotation. These results are inconsistent with the mental rotation concept but also cannot be explained assuming a mere rotational invariance. Our study thus seems to support the idea of information processing systems evolving gradually in response to specific ecological demands.