Conditional loop not working

[Altr37]

Hi,

I am trying to create a condition where only some trials will be presented and used a conditional loop as you offered before, but it did not seem to work for me.
My stimuli are defined and saved under a separate file, in the format:

{
  sentence: "The bla bla. ",
  question: "Was the bla bla?",
  correct_response: "j",
  condition: "v1",
  task_part: "sentences",
}

For some trials, I do not want to present a question, and instead, under question I have null.

Unfortunately, the condition does not work as I wanted, and instead of presenting no question, it preset the word null as a question.

The code:

                 var sentence = {
                     type: 'html-keyboard-response',
                     stimulus: function() {
                         return '<span style="font-size:25px;">' + jsPsych.timelineVariable('sentence', true) + '</span>';
                     },
                     choices: ['space'],
                     post_trial_gap: 500,
                     prompt: '<br><br> Press the space bar to continue',

                 };

                 var cursor_off = {
                     type: 'call-function',
                     func: function() {
                         document.body.style.cursor= "none";
                     }
                 };

                 timeline.push(cursor_off);

                 var question = {
                     type: 'html-keyboard-response',
                     stimulus: function() {
                         return '<span style="font-size:25px;">' + jsPsych.timelineVariable('question', true) + '</span>';
                     },
                     choices: ['f','j'],
                     post_trial_gap: 1000,
                     prompt: '<br><br> NO - <strong>F</strong>  YES - <strong>J</strong>',
                     data: {
                         sentence: jsPsych.timelineVariable('sentence'),
                         question: jsPsych.timelineVariable('question'),
                         condition: jsPsych.timelineVariable('condition'),
                         correct_response: jsPsych.timelineVariable('correct_response'),
                         task_part: jsPsych.timelineVariable('task_part'),
                         trial_part: 'question',
                      },
                     on_finish: function(data) {
                         var acc = false;
                         if (data.correct_response == jsPsych.pluginAPI.convertKeyCodeToKeyCharacter(data.key_press)) {
                             acc = true;
                         }
                         data.accuracy = acc;
                     }
                 };

                   var question_conditional = {
                   timeline: [question],
                   conditional_function: function() {
                     // check whether or not the question trial should be presented
                     if (jsPsych.timelineVariable('question') == null) {
                       return false;
                     } else {
                       return true;
                     }
                   }
                 }



                 var sentence_procedure = {
                     timeline: [sentence, question_conditional],
                     timeline_variables: main_sent_info,
                     randomize_order: true
                 };
                 timeline.push(sentence_procedure);

I have tried first to print to console the question, and could not find a way that presented the question itself. Maybe it's because I'm not saving the data as I go along just at the end?
I've tried:

var trial_sent=jsPsych.timelineVariable(main_sent_info); //presents the entire stimuli list
console.log(trial_sent);

and:

var trial_sent=jsPsych.timelineVariable(main_sent_info); //presents general stimulus info, at the beginning, without changing every trial 
console.log(trial_sent.question);

and:

var trial_sent = jsPsych.data.getLastTrialData(); // same as before, general info, at the beginning of the exp, not changing
console.log(trial_sent);

I'm not sure how to refer to the actual question I need for the condition to be compared properly.
I will appreciate and help!

[becky-gilbert]

Hi @Altr37, I can't remember what version of jsPsych you're using, but if it's not the most recent version then you may need to add the second true argument to `jsPsych.timelineVariable('question') inside your conditional function, like this:

var question_conditional = {
  timeline: [question],
  conditional_function: function() {
    // check whether or not the question trial should be presented
    if (jsPsych.timelineVariable('question', true) == null) {      // <--- added true argument here
      return false;
    } else {
      return true;
    }
  }
}

Also, just to check: in the cases where you don't want a question, is the question value just the word null (with no quotes around it), like this?

{
  sentence: "The bla bla. ",
  question: null,
  //...
}

Finally, when trying to debug this problem, it wasn't clear to me where you were putting the console logs in the last part of your question. What I would do is try to see what the value of question is on each trial by printing it out in the conditional function, before the if statement, like this:

var question_conditional = {
  timeline: [question],
  conditional_function: function() {
    // check the value of 'question' on this trial
    var question = jsPsych.timelineVariable('question', true);
    console.log('question: ', question);                     // <---- added console.log here
    // check whether or not the question trial should be presented
    if (jsPsych.timelineVariable('question', true) == null) { 
      return false;
    } else {
      return true;
    }
  }
}

Does this help at all?

[Altr37]

It worked, thank you so much! I just added the 'true'.
Thank you for your help!