By jm2209 - 8/28/2012
Hello,
I am after some advice regarding a timing discrepancy I have discovered within my research. I've been using Inquisit 3 to run a customised IAT, while also measuring physiological responses through a separate system. Although both methods were started and ended at the same time, the combined RT's and set instruction blocks (timeout 30000ms) do not equate to the total (actual) time elapsed. After doing a bit of digging I have noticed that I had left the post trial pause at 250ms, which explains some of the time difference, but not all of it.
Is there something else within the software that I may be missing or could it be a hardware issue etc?
Thanks in advance,
John
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By Dave - 8/28/2012
Your stimuli's /erase settings may introduce additional frames. One at the end of every trial if erase=true (which is the default). Generally see the "How to Control Trial Duration and Inter-Trial Intervals" and "How to Erase Stimuli" topics in the Inquisit documentation.
Also, stimulus display depends on your monitors refresh rate. Additional discrepancies may be introduced if your timings don't match the refresh cycle.
All of this has been discussed previously, e.g. at http://www.millisecond.com/forums/Topic4796.aspx.
Regards,
~Dave
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