0.101 seconds is the current fastest reaction time recorded for human beings. The average reaction time of human beings is around .215 seconds. This is determined by the amount of time it takes for people to react when given the proper signal to click.
The amount of time it takes for human beings to react may sometimes be affected if people know that they should react. The gadget that is used for measurement also affects the recorded time. Mobile phones and tablets may take longer than a mouse click, but even using a laptop may cause a few milliseconds of delay.