This article explains important matters in analyzing the behavior of the driver using simple DS and advanced DS of this laboratory, and full-scale DS as in Leeds University. At first, the measurement of the response time of the driver.
In the analysis of the driver behavior of DS, the most important thing is the response time. The time from the presentation of the stimulus to the response is defined as the response time, and the stimulus is called the trigger signal. As a task which examines the response time, there are simple response task which looks at the single response for the single stimulation and selection response task which chooses from multiple alternatives according to the content of the stimulation. As the number of stimuli and alternatives increases, the reponse time increases, and according to Hick's law, the response time is proportional to the logarithm of the number of alternatives + 1. This is the entropy of choice. The time from the trigger signal to the reponse is called Trial, and the time between trials is called trial interval time ITI (Inter Trial Interval). When ITI is fixed, the subject predicts the next stimulation, so it is important to change it at random.
The response time is different, when the preparation signal is given before the stimulus signal presentation. The response time becomes the shortest when the preceding time is 250 ms from the preparation signal to the stimulation, and the response time becomes long even if it is over or under. The response time is affected by the preparation state of the subject, and the response time is shortened, when the preparation state can be made by the subject. And, since response time is also stabilized in this state, an experimental scenario to make a preparation state is required.
And, the response time is different by stimulus content, type, intensity of the stimulation and size of the noise. The response time is also different by the sense type, and when it is compared in the representative sense types of visual sense, auditory sense and tactile sense, it becomes earlier in the order of tactile sense, auditory sense and visual sense. In the simple response task, the representative value of the auditory stimulation becomes 200 ms, and in the visual stimulation, it becomes from 200 to 250 ms. The stronger the stimulus, the shorter the reponsen time, and the longer the noise is added. In the response site, the arm is faster than the leg, and in the arm, the finger is faster than the arm. When a button is pressed and released, the release response is faster. The response of pedal operation is faster when the pedal is released than when it is depressed. The response time also depends on the suitability of the stimulus and response. For example, the response time is shorter when the right button is pressed with the right stimulus, and longer when the left button is pressed with the right stimulus. In the case of the selective response, the response time differs according to the appearance probability of the stimulation. The higher the frequency of appearance, the shorter the response time, and the lower the frequency, the longer the response time.
The response time has an ordering effect and is affected by previous trials. For example, when there are two alternatives, the same stimulus has a shorter response time and the opposite stimulus has a longer response time. However, the effect disappears, if the time between stimulation is lengthened. When the time between stimuli is short, the repetitive effect is generated, and the accelerating effect for the response is produced. Therefore, an experimental design to eliminate the ordering effect is required. The response time also changes with the elapsed time of the experiment. The response time is short just after the start of the experiment and becomes almost constant afterwards, and the response time becomes longer as the experiment time becomes longer. However, the response time becomes shorter at the end of the experiment. The phenomenon that the response time becomes short at the end of the experiment is called the termination effect. When the subjects know the end of the experiment, they concentrate on the task.
Response time is measured in milliseconds. Thus, stimuli that can be presented within 1 ms are used. The PC screen is often used for visual stimulation, and the display characteristics on PC should be understood. For example, a refresh rate of 60 Hz can cause a delay of 16 ms, which may be unsuitable for experimental purposes.
In the stimulation by the sound, the simple sound is not especially a problem. However, in the case of speech, the definition of the start time becomes difficult because the rise is slow. Similarly, the definition of response time is difficult when speech is a response. And for the finger or foot response, the selection response task requires a contrivance that equalizes the distance between each finger or foot and the selection button.
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