[solved] RT measurement with stimulus->mask sketchpads

Comments

• rhettclayton

  February 2016 edited 5:44AM

  Edit: I may have worked out a workaround. The fixation cross goes up for two seconds. The stimuli for 300ms, and the response screen, being the final screen, goes up for 1 ms. Then the keyboard logger, I presume, runs from the last object, so if I want to measure from stimulus presentation to the time a participant kits a key, it would be 300ms + 1ms + [whatever ms response time OpenSesame logs].
• Josh

  February 2016 edited 5:44AM

  Hi,

  Indeed, the response time indicates the time from the moment your keyboard item started. If you want participants to be able to respond during the stimulus presentation time, however, this is problematic, (participants can only respond after the 300ms stimulus time).

  If you want to change this, you can set the stimulus sketchpad to 0 ms, and set a new keyboard response item right after that with a timeout of 300 ms. Now you only want the response screen and subsequent (2nd) keyboard item to be used if participants didn't respond during those first 300 ms. To do this, click on your sequence item to reveal a list of run-if statements. For the response sketchpad and second keyboard item, you can enter the run-if statement keyboard_response = None

  Now, you just need to add 300 ms to your response time if the second keyboard item is run. You can add an inline_script after the keyboard item, with the same run-if statement, and in the run phase of this inline script add the following line of code:

    exp.keyboard_response += 300
  

  Cheers,

  Josh
• rhettclayton

  February 2016 edited 5:44AM

  Hey Josh,

  To get your recommendation working, I had to set the run-if of response_time to 295, and the inline script to response_time += 300, however as it runs after the secondary keyboard logger, the script will only run if the participants' RT is exactly 295. How can I get around this? I tried to run the entire secondary process within a sequence, but that also error-ed out?

  Also when trying to run the script to add 300 to the response_time variable just on it's own, to test it, 300ms is never added to the score. I am using exp.response_time += 300

  Thanks a lot for your help,

  Rhett
• rhettclayton

  March 2016 edited 5:44AM

  Hey Josh (or others)

  Please mark this as problem solved

  Thanks a lot!

  Rhett