Time of sketchpad and keyboard response

Comments

• Josh

  May 2016 edited 8:18PM

  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
• guipru

  May 2016 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
• Josh

  May 2016 edited 8:18PM

  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
• guipru

  May 2016 edited 8:18PM

  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
• guipru

  May 2016 edited 8:18PM

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

  May 2016 edited 8:18PM

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