By Diane - 4/12/2015
Hi,
I want to present trials to which participants can respond, but the response should not end the trial. That is, I want the trial to last exactly 3500 ms no matter how fast the participant responds. I've tried various settings of trialduration, timeout, response = timeout, but none of them works.
Thanks.
Diane
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By Dave - 4/12/2015
Depending on the exact behavior you want, you need to specify the desired /trialduration, /beginresponsetime and/or /responseinterrupt mode for the <trial>.
Example:
<trial mytrial>
/ stimulustimes = [0=a; 1000=b; 3000=c; 4000=d; 5000=e]
/ trialduration = 6000
/ responseinterrupt = frames
/ beginresponsetime = 0
/ validresponse = (57)
</trial>
<text a>
/ items = ("A")
</text>
<text b>
/ items = ("B")
</text>
<text c>
/ items = ("C")
</text>
<text d>
/ items = ("D")
</text>
<text e>
/ items = ("E")
</text>
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By Diane - 4/12/2015
Thanks!
What is the difference between responseinterrupt = frames and responseinterrupt =trial?
Diane
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By Dave - 4/12/2015
That's covered in the language reference topic for the /responseinterrupt attribute (reproduced below):
immediate:
Any remaining stimulus presentation frames are aborted when the subject responds, and the stimuli are immediately erased.
frames:
Any remaining frames in the trial are presented before the stimuli are erased.
trial:
Any remaining frames in the trial are presented before the stimuli are erased. Any media stimuli (sound or video) are played to completion before Inquisit advances to the next trial.
Remarks
If beginresponseframe is not set to a value to that allows a response during the stimulus presentation sequence, then immediate and frames are functionally equivalent. The default setting is immediate.
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By Diane - 4/12/2015
Sorry, yes, I read that, but didn't understand it. I should have formulated my question differently: What is meant by "remaining frames"? The trial in your example consists of several text elements that are timed in milliseconds, not frames, so what does "frame" refer to here?
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By Dave - 4/12/2015
Everything ultimately comes down to display *frames*, that's what your monitor works with. For the purpose of your question, "frames" just means anything that's specified in the <trial> element's /stimulusframes or /stimulustimes attribute.
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By Diane - 4/12/2015
So in your example setting responseinterrupt to trial or frames has the same effect?
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By Dave - 4/12/2015
Yes.
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By Diane - 4/12/2015
Actually, it doesn't seem to work the way I want. Here's my trial:
<trial massedstudy1>
/ stimulustimes = [1=massed1]
/posttrialpause = 500
/trialduration = 3500
/responseinterrupt = frames
/ validresponse = (44,53)
/ correctresponse = (44)
</trial>
I wanted the stimulus (massed1) to remain on the screen for 3000 ms no matter when the response occurs, but setting responseinterrupt to either frames or trial does not do that. Can you suggest another solution?
Thanks
Diane
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By Dave - 4/12/2015
There is only one frame
/ stimulustimes = [1=massed1]
hence /responseinterrupt = frames will have no effect (there are no further frames to display) and the stimulus will be erased. That's the expected behavior. Note that the trial *will* nevertheless last 3500ms in total.
What you need to do is set massed1's /erase attribute to false.
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By Diane - 4/12/2015
I tried that, but now the stimulus remains on the screen during the posttrial pause. I wanted it to remain on the screen for 3000 ms, followed by a 500 ms blank screen.
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By Dave - 4/12/2015
Then you ought to do something like
<trial massedstudy1>
/ stimulustimes = [0=massed1; 3000=massed1]
/posttrialpause = 500
/trialduration = 3500
/beginresponsetime=0
/responseinterrupt = frames
/ validresponse = (44,53)
/ correctresponse = (44)
</trial>
with the stimulus' /erase attribute set to true.
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By Diane - 4/12/2015
Thanks, that works. I'm not sure I understand why, is it because now there is another frame (3000=massed1)? And it doesn't actually show this one?
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By Dave - 4/12/2015
Yes, there are additional frames and they *are* shown. You don't notice because the stimulus is, of course, identical.
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By Diane - 4/12/2015
Okay, thanks. I think I got it, but it is counterintuitive to set the text to erase when you actually want it to remain for a specific time. Anyway, thanks for your help!
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