[open] Looping a visual discrimination task while waiting for a key press to terminate trial?

Comments

• lvanderlinden

  December 2013 edited 1:50AM

  Hi,

  Sorry for the delay! In order to simultaneously wait for participants' keyboard responses on the primary task, as well as for a response from the experimenter to break out of the block loop, you could do something like the following:

  Firstly, build your experiment like normally, but add a 'break-if' statement in the block loop. In the example below, OpenSesame will break out of the block loop when someone (in your case the experimenter) presses 'q'.

  

  Secondly, add an inline_script item and a logger item (the same one as you use within the trial sequence!!) to the end of your block sequence (see screenshot above). The purpose of these items is to log the total time of the primary task. To achieve this, put something like the following Python code in the Run phase tab of the inline_script:

  primary_task_rt = self.time() - self.get('time_sketchpad_onset')
  exp.set('primary_task_rt', primary_task_rt)
  

  where the sketchpad_onset item is just a dummy item to start the timing for the primary task duration (see screenshot above).

  Finally, to avoid that last trial of a given trial block loop from occurring twice in your output file (since it is logged once in the trial_sequence, and once after the experimenter made the experiment break out of the loop), set the Run-if statement of the logger item in the trial sequence to:

  [response] != q
  

  such that it only logs the keypress (i.e. foot-pedal press) if the keypress is not 'q' (in which case the trial will be logged by the logger in the block sequence).

  

  I uploaded an example experiment here (download, change the extension to .opensesame, and open as normally):

  • http://pastebin.com/FFSCMQ5c

  I hope this helped!

  Cheers,

  Lotje

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• cjp87

  December 2013 edited December 2013

  Thanks for the response, very helpful, especially the example. I'm having an issue though. In my program, I keep getting the error:

  "Variable "response" is not set in item (loop's name). You are trying to use a variable that does not exist. Make sure that you have spelled and capitalized the variable name correctly."

  I assume this is referring to the "break if" statement. I used the variable inspector, and "response" is listed as an available variable. I was also running into a similar issue earlier when I defined an ISI variable (using one of your answers to someone else's question here: http://forum.cogsci.nl/index.php?p=/discussion/240/solved-variable-interstimulus-interval-isi/p1), it would say that my ISI variable didn't exist as well (despite showing up in the inspector). I'm using the latest version of OpenSesame on Windows, is there something that I'm missing causing these issues? Your program seems to work just fine, for what it's worth.
• lvanderlinden

  December 2013 edited 1:50AM

  Hi,

  In my program, I keep getting the error: "Variable "response" is not set in item (loop's name). You are trying to use a variable that does not exist. Make sure that you have spelled and capitalized the variable name correctly."

  I see what you mean! As you may have guessed, this error message means that you're trying to use the variable 'response' before it has been set (i.e., exists and has a starting value).
  In the example I uploaded, this was not the case because a first keyboard response was already collected with the 'instruction' sketchpad (see overview above). As a consequence, the variable 'response' already existed when we were using it in the block loop.

  In your program, this is probably not the case (i.e. you don't collect any responses before the block loop item). Therefore, I think you could simply set the variable 'response', and give it a dummy value, in an inline_script at the very start of your experiment. (This value will never appear in your output file, because it will immediately be overwritten by your first trial.)

  

  New example:

  • http://pastebin.com/t1m7SS8U

  I was also running into a similar issue earlier when I defined an ISI variable.

  Could it be that in this case you defined the variable ISI in the Run phase tab rather than the Prepare phase tab, of your inline_script item?

  To familiarise yourself with OpenSesame's prepare-run strategy, perhaps you could read the following:

  • http://osdoc.cogsci.nl/usage/prepare-run/

  Please let us know if you have more questions!

  Cheers,

  Lotje

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• cjp87

  December 2013 edited 1:50AM

  I think I've got it working. Looks like I'm getting accuracy data, monitoring task RT data, and primary task times (took me awhile to see that you had another sketchpad in there to serve as the onset, and once I got that it fixed my last problem), and the "break if" statement works now as well. I just did a mini-version of the experiment, and everything I want seems to be coming out in the report.

  Thanks a ton for the help. Now all I have to do is make all the conditions/variables for the full experiment.

  As a comment, I'd like to applaud both the developers for OpenSesame and the members of this help forum. Each time I've made an experiment with this program, it's been because I got frustrated with my previous experimental design software. And each time I've asked for help here, I've gotten quick replies that helped me work through to fix the problem. Further, using OpenSesame feels more like a puzzle to be figured out than a chore to be overcome, and I think that should be applauded as well.
• lvanderlinden

  December 2013 edited December 2013

  Thank you very much. That's really nice to hear!
  Good luck with your experiments!!

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