Zonotech Audio Visual Reaction Timer

Product Details :

• Simple Reaction Time

Problem

• To determine simple reaction time of the subject for visual stimuli.

Introduction

In 1786 Maskelyne, Royal Astronomer at the Greenwich Observatory, dismissed his assistant, Kinnebrooke,who observed the times of star movements almost a second later than he did. Such an error was considered unpardonable because the calibration of clocks to determine the standard time depended on the correct observation of the place and time when the stars were seen. It was not until 1819 that a personal difference was discovered by the German astronomer, Bessel,who found an average difference of 1.041 seconds between him and another observer. Kinnebrooke's error was of the order of 0.8 second. This difference came to be called the personal equation, and was found to very with different individuals between 0.770 and 1.021 seconds. In order to minimize errors due to this personal equation, the chronograph and chronoscope were invented. By 1892,the Hipp Chronoscope was brought into use . This timing device measures time intervals in thousandths of a second, or milliseconds. Eventually , it was realized that at the human level, there is a measurable time lag between the appearance of a signal and the response to it . Research in experimental psychology has , since that time, made great strides forward in the exact measurement of what today goes by name of Reaction Time or response time.

One of the classical experiments of the psychological laboratory concerns the speed with which a stimulus elicits a response. The reaction time experiment has had a long history and still is a standard procedure in experimental psychology. It has remained a sensitive measure of the readiness of the organism or preparedness varies both with the stimulus situation as well as the sets and attitudes of the organism. "Time ", as woodworth says," as a dimension of every mental or behavioural process, lends itself to measurement, and can be used as an indicator of the complexity of performance or of the subject's readiness to perform…

Faulty procedures have been tried and found Unworkable, problems hopefully attacked have been found insoluble by the use of reaction time , and the reasons for these failures , as well as the sucesse's are really quite important contributions to the science of psychology". In the simple reaction time situation, the observer is instructed to respond to a single stimulus by withdrawing his finger from a key as soon as possible . The sense modality stimulated is an important parameter of every reaction time experiment. Speed of response varies with different sense modalities, as will be evident in Table

Typical Ranges of Simple Reaction Time

Sense Modality                              Range in ms

Touch (pressure stimuli)                 110 - 150

Hearing (sound stimuli)                  120 - 160

Vision ( Lights )                              150 - 200

Within any given sense modality, reaction time varies considerably with the specific characteristics of the stimulus. An intense stimulus produces a response of greater magnitude in the sense of organ a weak stimulus. In the case of visual stimuli, effective stimulation depends not only on the intensity of the stimulus but also on the duration, size, and location of the area stimulated. Increases in the duration of visual stimuli and the area of visual stimulation also shorten reaction time. The correlation between speed of reaction and effectiveness of stimulation appears also when the observer responds to a change in the level of stimulation. The greater the change introduced in the experiment, the faster will be the reaction time. Reaction time to change is faster at a medium level of intensity than at a low level but slower at a high level than at a medium level.

This system is used in various Psychological institutes to detect the reaction time of the persons. Somewhere it can be used as IQ testing instrument also. There are two sides in the instrument-Experimentor side & the Trainer side.A sheet separates the two sides. There are two modes of function- Light & sound. Any of these two functions can be selected by a mode switch. There are four switches as well as four no.of L.E.D's on both sides. The switches in the Experimenter side are to glow the lights, while,the switches in the Trainer side are to OFF the lights. First select the light mode & glow any light among the four &a