Conditional trial after set number of errors

[gezelle-d]

Hi, I have a task that presents a series of colour words in different colours (much like the stroop test). In my task, participants respond with 'a' if the word and the colour are not the same (i.e., lure = 0) and respond with a number (1, 2, 3, or 4) if the word and the colour are the same (i.e., lure = 1). When participants make two consecutive lure errors (i.e., they press 'a' on two lure trials in a row), I would like to present them with a conditional trial immediately following the second error. Below is a snippet of my code (with just a subset of the trial stimuli). I have created a variable called feedback and would like to create a conditional function for this but am not sure how to go about it. Essentially I need to keep track of the participant's response on the previous lure trial. If the previous lure and the current lure are both incorrect then a feedback trial is presented. Once the feedback trial is presented, this 'error count' should be set back to zero and will begin again the next time they make a lure error. Thanks in advance!

    var  test_stimuli =  [
      {
        "stimulus": "<p id = 'stroop_stim' style = 'color: red; font-size: 60pt;'>red<\/p>",
        "data": {
          "word": "red",
          "color": "red",
          "lure": 1
        }
      },
      {
        "stimulus": "<p id = 'stroop_stim' style = 'color: green; font-size: 60pt;'>red<\/p>",
        "data": {
          "word": "red",
          "color": "green",
          "lure": 0
        }
      },
      {
        "stimulus": "<p id = 'stroop_stim' style = 'color: blue; font-size: 60pt;'>red<\/p>",
        "data": {
          "word": "red",
          "color": "blue",
          "lure": 0
        }
      },
      {
        "stimulus": "<p id = 'stroop_stim' style = 'color: yellow; font-size: 60pt;'>red<\/p>",
        "data": {
          "word": "red",
          "color": "yellow",
          "lure": 0
        }
      },
      {
        "stimulus": "<p id = 'stroop_stim' style = 'color: red; font-size: 60pt;'>green<\/p>",
        "data": {
          "word": "green",
          "color": "red",
          "lure": 0
        }
      },
      {
        "stimulus": "<p id = 'stroop_stim' style = 'color: green; font-size: 60pt;'>green<\/p>",
        "data": {
          "word": "green",
          "color": "green",
          "lure": 1
        }
      },
      {
        "stimulus": "<p id = 'stroop_stim' style = 'color: blue; font-size: 60pt;'>green<\/p>",
        "data": {
          "word": "green",
          "color": "blue",
          "lure": 0
        }
      }
    ]

    var test = {
      type: "html-keyboard-response",
      response_ends_trial: false,
      stimulus: jsPsych.timelineVariable('stimulus'),
      data: jsPsych.timelineVariable('data'),
      on_finish: function(data){
          var correct = false;
          if(data.lure == 0 &&  data.key_press == 'a'){
              correct = true;
          } else if(data.lure == 1 &&  data.key_press != 'a'){
              correct = true;
          }
      data.correct = correct;
  },
      choices: ['a', '1', '2', '3', '4'],
      trial_duration: 500,
      post_trial_gap: 600
    }

    var feedback = {
        type: 'html-keyboard-response',
        stimulus: '<span style = "font-size: 60px;">?</span>',
        choices: jsPsych.NO_KEYS,
        trial_duration: 1500,
        post_trial_gap: 600,
        conditional_function: function() {
        }
      }

    var test_procedure = {
      timeline: [test, feedback],
      timeline_variables: test_stimuli,
      randomize_order: false,
      repetitions: 0
    }

[trig11]

Hi,

a while back I had a similar problem. The solution posted here (#748) might help you.

[gezelle-d]

Thanks for your reply. Unfortunately I still can't get it to work. It just displays the feedback trial after every trial.

    var feedback = {
        type: 'html-keyboard-response',
        stimulus: '<span style = "font-size: 60px;">?</span>',
        choices: jsPsych.NO_KEYS,
        trial_duration: 1500,
        post_trial_gap: 600,
        conditional_function: function() {
            var nTrials = jsPsych.data.get().filter({lure: 1}).count(); 
            if (nTrials >= 2) { 
                var counter = jsPsych.data.get().filter({lure: 1}).last(2).filter({correct: false}).count(); 
                if (counter == 2){
                    return true;
                } else {
                    return false;
                }
            }
            else {
                return false;
            }
        }
      }

[trig11]

I think the issue is that you need to separate elements: One is the feedback screen itself (your html-keyboard-response) and the second one is the conditional timeline.

So you will need to define your feedback screen (without any conditional function defined). Then create another variable which is the conditional timeline.

var conditional_time = {
     timeline: [feedback],
     conditional_function: function() {
    // your function here which returns true for the cases you want to display the feedback screen
    }

}

Then only push the conditional_time element to your timeline and not the feedback screen itself.

[gezelle-d]

Thanks again. It's still not working though. I'm not getting any feedback trials at all. I assume the issue is now in the conditional function itself, unless I have messed up the timelines again (I'm new to all of this!). Thank you so much for your help so far.

    var feedback = {
        type: 'html-keyboard-response',
        stimulus: '<span style = "font-size: 60px;">?</span>',
        choices: jsPsych.NO_KEYS,
        trial_duration: 1500,
        post_trial_gap: 600,
      }

    var conditional_time = {
        timeline: [feedback],
        conditional_function: function() {
            var nTrials = jsPsych.data.get().filter({lure: 1}).count(); 
            if (nTrials >= 2) { 
                var counter = jsPsych.data.get().filter({lure: 1}).last(2).filter({correct: false}).count(); 
                if (counter == 2){
                    return true;
                } else {
                    return false;
                }
            }
            else {
                return false;
            }
        }
    }

    var test_procedure = {
      timeline: [test, conditional_time],
      timeline_variables: test_stimuli,
      randomize_order: false,
      repetitions: 0
    }

timeline.push(test_procedure)

[trig11]

The general logic looks fine to me. It seems like the conditional function never returns true then. I guess that there might be some minor issue with defining the nTrials and counter variables.

I would suggest to use console.log to debug this (i.e., make sure the nTrials and counter variables work as they should). To do so, you can include the following statements in your code:

console.log(nTrials); // after the line where nTrials is defined
console.log(counter); // after the line where the var counter is defined

Then, after each trial you should be able to see these variables pushed to your browser's console (F12 to open it in Chrome and Firefox), so that you can check what is used in your conditional function.

[gezelle-d]

Thank you so much for your help. I got it to work. The code is below for anyone who attempts a similar thing.

    var conditional_time = {
        timeline: [feedback],
        conditional_function: function() {
            var nTrials = jsPsych.data.get().filter({stim_type: 1, correct: false}); 
            if (nTrials.count() >= 2 && jsPsych.data.getLastTrialData().values()[0].stim_type == 1) {
                var counter = nTrials;
                if (counter.count() % 2 === 0){
                    return true;
                } else {
                    return false;
                }
            }
            else {
                return false;
            }
        }
    }