RE: Negative Stimulus Onset Times

Back

Negative Stimulus Onset Times

Author	Message
asali	asali posted 5 Years Ago Topic Details Share Topic
Group: Forum Members Posts: 3, Visits: 52	Hello, I'm new to using Inquisit and have been going through the tutorials while writing my own code. I've been puzzled that in both my code and in the tutorials, I am getting negative numbers in the data file under stimulusonset. I've attached a data file from the CovertAttention tutorial. I'd like to verify the accuracy of the timing of my system. Does the negative mean that the stimulus is appearing prior to when the trial was expected to start? Thanks for your help in advance! Best, Anthony Attachments CovertAttention.dat (374 views, 35.00 KB)
	Reply Like 26
Dave	Dave posted 5 Years Ago ANSWER Post Details Share Post
Group: Administrators Posts: 13K, Visits: 104K	+x asali - 8/7/2019 Hello, I'm new to using Inquisit and have been going through the tutorials while writing my own code. I've been puzzled that in both my code and in the tutorials, I am getting negative numbers in the data file under stimulusonset. I've attached a data file from the CovertAttention tutorial. I'd like to verify the accuracy of the timing of my system. Does the negative mean that the stimulus is appearing prior to when the trial was expected to start? Thanks for your help in advance! Best, Anthony A negative onset would usually indicate some issue with respect to syncing to the system's graphics card / display refresh rate. The timings in the file appear internally consistent, but there may be some off-by-one frame issue. Try updating your graphics card driver and make sure there is no other application running in the background that might interfere with the display system while Inquisit is running.
	Reply Like 18