Accuracy rate and verbal decision task

Comments

• eduard

  November 2017

  Accuracy in opensesame is determined based on the variables var.correct_response and var.response. If they are the same, the variable var.correct will evaluate to 1, otherwise to 0. var.acc is the accumulated score of var.correct divided by the total number of trials (per block, or since the last time the feedback was reset).

  So, if your logfile has undefined accuracy scores, you probably haven't defined the correct response. Given your design, the location to do that is the loop table just add a column with the label correct_response and specify what is the correct response for a certain condition.

  Good luck,
  Eduard

  
• Siilvz

  November 2017

  Thank you very mutch for your response !

  Now i would like that the open sesame only consider the reponse linked to the target reponse ?

  In fact, the verbal decision is an ongoing task, the only things taht interesting me, is if the subject repond "space" to the target words

  Practicaly, i would like that the accuracy rates increase and decrease with the "space" responses but remains unchanged with the others keyboard responses.

  Is it possible?
• eduard

  November 2017

  That is a little trickier. In this case, I think you have to define your own accuracy and can't use Opensesame's default one. Probably best to use an inline_scripts. Once in the beginning of either your experiment or a block (depending on whether you want your feedback to be reset), you have to initialize a three variables, let's say:

  var.myAcc = None
  var.totalCorrect = 0
  var.totalNoTrials = 0
  

  Later, you have to make use of another script, which you put it in your trial loop, after the keyboard response, but before the logger. And the code needs to be in the runphase

  if var.correct_response == 'space': 
      var.totalNoTrials += 1 # increase the number of trials that go into the calculation of the accuracy
      if var.response == var.correct_response:
          var.totalCorrect += 1 # if correct response given increase that counter
     var.myAcc = float(var.totalCorrect)/var.totalNoTrials # compute new accuracy
  

  These variables should then be present in your logfile.

  Hope it helps.

  Eduard