Random Time Intervals

[GatorNeedsAid]

Hello-

I want to create a reaction time task with DrectRT and would like the stimulus to have a random interval of time between displays. I know you can set a fixed interval in styles (under options). Is there a way to make the interval a random amount of time between given boundaries limits?

Thanks-
Joe

[jarvis24]

Hi Joe,
Do you want them be be truly random or do you want oto ensure that there are an equal number of various values (e.g., 500, 1000, 1500)?
-Blair

[GatorNeedsAid]

Hello-

Really, it doesn't matter to me. I just don't want our subjects to be able to get into a pattern of hitting the response key after a fixed period of time. If you could explain how to do both options that would be great.

Thanks.

[jarvis24]

OK, check this out:

http://www.empirisoft.com/directrt/help/directrt_using_random_values.htm

e.g., you should be able to just enter something like rand(500,1000,1500) in your Time column.

Hope that helps,
Blair

[jarvis24]

[edited from related support email]

I am interested in setting different inter-trial intervals for a lexical decision task that I am programming. I believe that inter-trial interval is set in the Options window under the Style Editor, but I was only able to apply one inter-trial interval to all the trials in my experiment. I would optimally like to have Direct RT randomly select an inter-trial interval from a list of a few (e.g., 4) – do you know if this is possible?

As above.