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Time of sketchpad and keyboard response

edited May 2016 in OpenSesame

Hello,
Yet me...
I would like to present a stimulus during 250 ms and subject respond to this stumulus with key pressed. But I don't know how maintain the same sketchpad after 250 ms.
If I add a new sketchpad with no stimulus I must press twice the key...
Thank you for your help.
Guillaume

Comments

  • edited 1:16PM

    Hi Guillaume,

    I don't understand your problem completely. Do you mean you want to present the sketchpad for 250ms, even if subjects respond quicker?

    Cheers

    Josh

  • edited May 2016

    Hi,
    Not exactly. The stimulus appear 250 ms and disappear.
    Subject could respond during 5000 ms (250 + 4750 ms).
    But if I add a sketchpad for complete the stimulus (4750) I must press twice the key.
    Sorry for the english...
    Guillaume

  • edited 1:16PM

    Hi Guillaume,

    Ok, the setup you need is one with the stimulus sketchpad at a duration of 0ms, followed by a keyboard item with a timeout of 250ms. After the keyboard item you place a copy of the stimulus sketchpad, with duration value 250 - [response_time]. This will make sure that the stimulus stays on for 250ms, regardless of whether a key is pressed in the meantime.

    After the 2nd stimulus sketchpad you place the second screen, again with a duration of 0 ms, and followed by a keyboard item with timeout of 4750. The only problem is that you don't want to run the 2nd keyboard item if participants already pressed a key. To do this, click on the sequence item and insert the following run-if statement for the 2nd keyboard item (and also for the stimulus-off screen): run-if [response] = 'none'. (Here, response is the key logged by the previous keyboard item).

    Hope this helps.

    Cheers

    Josh

  • edited 1:16PM

    Hi
    The sequence "cratch" with my sketchap mark with : 250 - [response_time]
    Argh!
    But in fact the first 250ms are not the main problem.
    How can I disappear my letter (cf previous post) but respond for these letters ?
    Cheers
    G

  • edited 1:16PM

    Finally, I just would like to present stimuli during 250ms and participant respond after without presence of stimuli. But the responses depend of these...

  • edited 1:16PM

    Actually, I use a SOA and a sketchpad with the same stimulus... but hidden (is black, like screen).

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