Shuffle choices pulled from timeline_variables #3358

kschuler · 2024-07-25T16:14:13Z

kschuler
Jul 25, 2024

I need to pull the choices parameter from the timeline_variables and shuffle them, but they are always displaying as [object Object] or causing errors. I think it has something to do with this similar issue: #2619

Here's a demo. Note that I used all the same choices for the demo (so I can detect shuffling), but in my study there is a different set of choices for each trial.

<!DOCTYPE html>
<html>
  <head>
    <title>My experiment</title>
    <script src="https://unpkg.com/[email protected]"></script>
    <script src="https://unpkg.com/@jspsych/[email protected]"></script>
    <script src="https://unpkg.com/@jspsych/[email protected]"></script>
    <script src="https://unpkg.com/@jspsych/[email protected]"></script>
    <link href="https://unpkg.com/[email protected]/css/jspsych.css" rel="stylesheet" type="text/css" />
  </head>
  <body>


  </body>
  <script>
    const jsPsych = initJsPsych({});

    // host for stims
    const s3bucket = 'https://nyc3.digitaloceanspaces.com/stims.childlanglab/shared-variation/'
    const sample_trials = [
        {object: `${s3bucket}obj-flower.png`, choices: ['po', 'null']},
        {object: `${s3bucket}obj-butterfly.png`, choices: ['po', 'null']},
        {object: `${s3bucket}obj-camilla.png`, choices: ['po', 'null']}
    ]

    // works, but i want to shuffle the choices 
    const unshuffled_choices = {
      timeline : [{
        type: jsPsychImageButtonResponse,
        stimulus: jsPsych.timelineVariable('object'),
        choices: jsPsych.timelineVariable('choices'),
        prompt: "Uses `timelineVariable` but doesn't shuffle",
        stimulus_height: 300,
        stimulus_width: 300
      }],
      timeline_variables: sample_trials
    }
    // shuffles the choices but does not generate from timeline_variables
    const shuffled_choices_text = {
        timeline : [{
        type: jsPsychImageButtonResponse,
        stimulus: jsPsych.timelineVariable('object'),
        choices: function() {
            let my_choices = ['po', 'null']
            return jsPsych.randomization.shuffle(my_choices)
        },
        prompt: "shuffles, but but does not use `timelineVariable`",
        stimulus_height: 300,
        stimulus_width: 300
      }],
      timeline_variables: sample_trials
    };

    // fails when i try to do what i want 
    const shuffled_choices = {
        timeline : [{
        type: jsPsychImageButtonResponse,
        stimulus: jsPsych.timelineVariable('object'),
        choices: function() {
            let my_choices = jsPsych.timelineVariable('choices')
            // also tried let my_choices = jsPsych.timelineVariable("choices", true)
            // and also tried to return jsPsych.randomization.repeat(my_choices, 1)
            return jsPsych.randomization.shuffle(my_choices)
        },
        prompt: "This one returns [object Object] or fails from jsPsych.timelineVariable()",
        stimulus_height: 300,
        stimulus_width: 300
      }],
      timeline_variables: sample_trials
    };


    jsPsych.run([
        unshuffled_choices, 
        shuffled_choices_text, 
        shuffled_choices
    ]);
  </script>
</html>

kschuler · 2024-07-25T16:21:59Z

kschuler
Jul 25, 2024
Author

Oh, I see the answer in the 8.0.0 changelog 🫣. There is a new function jsPsych.evaluateTimelineVariable() that retrieves the value. :)

Timeline Variables

The functionality of jsPsych.timelineVariable() has been explicitly split into two functions, jsPsych.timelineVariable() and jsPsych.evaluateTimelineVariable(). Use jsPsych.timelineVariable() to create a timeline variable placeholder and jsPsych.evaluateTimelineVariable() to retrieve a given timeline variable's current value.
jsPsych.evaluateTimelineVariable() now throws an error if a variable is not found.
jsPsych.getAllTimelineVariables() has been replaced by a trial-level save_timeline_variables parameter that can be used to include all or some timeline variables in a trial's result data.

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Shuffle choices pulled from timeline_variables #3358

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Shuffle choices pulled from timeline_variables #3358

kschuler Jul 25, 2024

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kschuler Jul 25, 2024 Author

kschuler
Jul 25, 2024

kschuler
Jul 25, 2024
Author