The intra-individual variability of reaction time

The intra-individual variability of reaction time Introduction 

It is known, that the reaction time depends on various factors like smoking, menstrual period, sleep etc. The question is whether the individual cycle time depends on the same factors or whether it shows some stability. 

The direct visualized cycle time was obtained by an automatic recognition program which defined a peak if the sum of rise and decline was greater than two in the distribution of reaction times for one finger. The time axis has been divided into 10 ms intervals. The recognition program measured the differences between the peaks, summed them up and computed the mean value. This mean difference between the peaks of the distribution is the direct visualized cycle time of this task. Because it is possible that one cycle does not occur in a distribution, distances between peaks similar to two cycle times obtained by method 1 are not used to compute the mean value. This would give a false mean value if two cycle times are considered as one. 

The recognition program computed the slope of the regression line by the same method as SPSS (and was validated by SPSS). 

In the repetition, the number of trials within the tasks vl 1 to vlOlO was reduced to 50 trials for each task. The number of trials in the remaining tasks was not reduced. 

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