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How can I measure reaction time in milliseconds?


Hi everyone!

I want to compare visual and auditory reaction times. First we will ask participants to press space when they see a specific picture between several pictures. Every picture will be shown for 2 seconds and the time will be calculated when that specific picture is shown till the participant press space in milliseconds. Please tell me that can I do it with a normal PC?(I don’t want the exact time, I just want to compare them.) and what function I should use to measure reaction time in milliseconds?
PsychoPy v1.8

Thanks in advance


Yes you can do that with a normal PC, in fact you can do it with just about any PC.

Check out the tools for handling time recording and time computations in numpy.


Hi Sam,

I understand that PsychoPy gives your response data in seconds.

In the Builder, to obtain your data in milliseconds, just add a Code component at the begining of your Routine, and in the End Routine window insert the following line:

thisExp.addData('StimuliResp.RT in ms', StimuliResp.rt * 1000)

where “StimuliResp” is the name for your object to respond to the stimuli (e.g., keyboard; the “in ms” note is useful to distinguish this variable in your data sheet).

Good luck with your experiment!



Hi Fer
I appreciate your help. It worked.


Great, Sam!

For this and your following requests, it really helps to click the option solved on the post.

This results useful for others users, to put attention on other posts and not in those already solved.

Good luck with your experiment!