Constrain NoGo trials in a Go-NoGo task

Comments

• eduard

  December 2018

  Hi James,
  can you share your experiment? I'd like to have a look.

  Eduard
• James Bartlett

  January 2

  Hi Eduard,

  I've attached here, and the constrain code is within the script of the block_loop component.

  I've been thinking, and I think I know the reason it's crashing. Each block has 25 trials, 20 go trials and 5 nogo trials. If I am constraining trial_type to a max repetition of 1, then it would not know what to do when there are several go trials in succession. If you have any advice on how I could just constrain the nogo trials, I would be very grateful.

  Best wishes,
  James
• eduard

  January 12 edited January 12

  Hi James,

  I don't really use use the loop functionalities a lot, so maybe there is an option to do that with those functions that I don't know about, but usually I solve these kind of problems programmatically. So just use an inline_script and create a possible trial sequence in the beginning of a block. Like this you have more control over the sequence, i.e. you can specify all kinds of constrains (if you manage to think about how to implement them). Here an example:

  import random
  
  def checkDuplicates(list, test_item):
      """
      Takes a list and checks whether there are duplicates of the test_items. Returns true, if there are duplicates
      """
      # loop over list items, starting at the second. If you encounter a nogo trial, check whether the previous trial is also a nogo trial. If so return true. If nothing like this was encountered, return False
      for idx,item in enumerate(list[1:]):
          if item == test_item:
               if list[idx-1]==test_item:
                    return True
      return False
  
  
  
  # make a list with all trials
  trials = ['go']*20 + ['nogo']*5
  
  # shuffle until no duplicates
  random.shuffle(trials)
  while checkDuplicates(trials,'nogo'):
       random.shuffle(trials)
  
  

  Hope this helps!

  Eduard
• James Bartlett

  January 14

  Hi Eduard,
  This looks like it would do the trick. Thank you very much.
  Best wishes,
  James