Abstract
A PC's clock, which has a precision in error of ±1 μs, was developed. However, the level of precision in a psychological experiment depends on the keyboard characteristic, if we use it. The author measured reaction time (RT) and interresponse time (IRT) using the PC's clock and, in parallel, measured true time with an external universal counter. Next, the time difference between the PC's time count and the true time value was analyzed. When using a keyboard as a reaction panel, both a constant time delay and an error variance were found in measuring the RT. The frequency distribution of this difference in time value had a uniform distribution with the width of 6ms. In the IRT time measurement, no time delay was found, and the frequency distribution of the difference in time value was triangular. The range of the triangle distribution was twice as large as that of the uniform distribution. We can estimate the standard deviations of both distributions through the relation of “σ/R=k” if we get a range of uniform distribution.
