Collect responses after target disappeared...?

[Piercarlo Mauri]

Hello, 

I'm new to this group and also to e-prime software, so please excuse me if the question will sound simple to you...I tried to find a solution online without any results...

I'm creating my first experiment in e-prime and will be a continous performance test (CPT), a series of digits will be presented each one for 200ms with a variable ISI between 800-2000 ms. Subject will have to press a button on a SRbox only to one specific digit (target ) while they don't have to press buttons to other digits. The problem is that the responses are not collected by EP after the duration of 200ms of the stimulus (I would like to allow a time limit of 800ms after the appearence of the target), I tried to extend timeLimit for the SRbox input but the response will not be recorded.

The experiment is divided in TrialList (list of digits presented in a random order), TrialProc with: Inline (to randomize the duration of fixation) / Fixation / Stimuli (with 200 of duration and timeLimit to 800 but EP doesn't collect responses after the 200ms of the stimulus). Can you help me?

Thank you 

PM

[KatrinH Heimann]

Ciao PierCarlo,

Two possibilities come to my mind

a) why not just putting another slide of 800 ms length after your stimulus slide. Just a black textslide I mean. Just make this slide also collect responses, but terminate always after 800 ms. This has the disadvantage of course that the trial does not end with the response. But maybe this is not the problem

If it is a problem I would make a short movieclip instead of the textslide-stimulus. That would mean filming a digit for the 200 ms (or putting frames of a picture in a movieformat to fill 200 ms, and then add another 800 ms of black in the movie. This movie can act as the stimulus and you can make the slide end with the response of the subject. Was that of any help?

Katrin

2013/6/4 Piercarlo Mauri <piercar...@gmail.com>

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[Piercarlo Mauri]

Thanks for your reply,

I tried to use slide after the target with a duration of 800ms showing a fixation point and I reduced the first fixation to 0-1200, in this way the subject will have 200ms of the stimulus + 800ms of the other slide to respond and it seems to work, but do I have to set time limit in the stimulus slide to 1000ms in order to allow a response in the stimulus slide (200 ms) and also in the next slide (800ms)? Will the reaction time be recorded also if the subject press the button during the stimulus or during the next slide?

[KatrinH Heimann]

You should just allow responses on both slides, you don't have to do anything else. Then you will either get a Reaction time for the first or for the second slide. In case two you would have to add 200 ms to make up for that. Is that clear enough? Best

Katrin

2013/6/4 Piercarlo Mauri <piercar...@gmail.com>

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[Piercarlo Mauri]

Sorry Katrin,

you mean that in case of response during the second response slide (the fixation cross of 800ms) I would have to manually add 200ms to response time in the data? (in order to include the first 200ms slide on the total time of response). Is this the only possible method?

Thank you

PM

[KatrinH Heimann]

well, what do you mean with manually? you will of course not change every number by hand, but either program that later in the database, or you can even do that with a copydemand in excel, right? Should take you not more than a few seconds...

best

katrin

2013/6/11 Piercarlo Mauri <piercar...@gmail.com>

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