Conditionally adding a value to an array based on previous trial data

[mcd710]

Hi there!

I've been working on a task for a few months now and I'm at the stage where I want to run it on Prolific, but I'm having trouble getting one last part to work. The task is a betting game, and I'm trying to award participants money based on their performance (and eventually display a screen at the end that says "you won x $"). There are four categories of images, and I'm trying to write a code that adds 0.05 to a pre-defined array of "money" based on whether they identified the image correctly. The names of the images are strings and I want to compare a subset of the strings (whether the string contains "ff", "fs", "ss", or "sf") to the response provided by the participant (either 0 or 1). I have three questions: (1) Since I have written and added countFunction() to my timeline, I keep getting the two errors "Trial level node is missing the "type" parameter" and "Uncaught TypeError: trial.type is not a constructor" – any ideas on how to fix this? (2) I tried to define my own function and put it in the timeline because I was not sure that there was a way within JsPsych to conditionally add data to an array based on the results of each trial. Is there a way I can use the JsPsych framework to accomplish this? (3) I'm not sure if I'm accessing the timeline data correctly when I, for example, write var image_data_ff_fs = jsPsych.data.getLastTimelineData().select('stimulus').subset(function(x){ return x = image_data.includes('ff' || 'fs')}). Does this look correct?

Any advice at all would be greatly appreciated.

Here is a relevant section of my code:

    /* initialize jsPsych */
    var jsPsych = initJsPsych({
      on_finish: function() {
        jsPsych.data.displayData();
      }
    });
    
    /* create timeline */
    var timeline = [];
    
    /* create empty array for payment to be added to */
    var money = [];

    /* function to add the bonuses */
    // CALL THIS FUNCTION IN "STIMULUS" AT THE VERY END //
    function moneyFunction() {
        let sum = 0;
        for (let i = 0; i < money.length; i++) {
            sum += money[i];
        }
        console.log(sum);
    }

// removed a lot of code here //

    /* define trial stimuli array for timeline variables */
    var test_stimuli = [
        {stimulus: 'images/easy-411-ss.png'},
        {stimulus: 'images/easy-538-sf.png'},
        {stimulus: 'images/easy-vcom=4-126-fs.png'},
        {stimulus: 'images/hard-570-sf.png'},
        {stimulus: 'images/hard-600-ss.png'},
        {stimulus: 'images/hard-vcom=1-50-ff.png'},
        {stimulus: 'images/hard-vcom=1-95-fs.png'},
// there are a lot more images, I deleted most of them
    ];


    /* define test trials */
    var test = {
        type: jsPsychImageButtonResponse,
        stimulus: jsPsych.timelineVariable('stimulus'),
        choices: ['fall ◄', 'stand ►'],
        randomize_order: true,
        trial_duration: 5000,
        post_trial_gap: 500
    };

// removed a lot of code here ... includes test, if_node//

    /* get data from last trial and add to bonuses */
    function countFunction() {
        var response_data_0 = jsPsych.data.getLastTimelineData().select('response').subset(function(x){ return x == 0; });
        var response_data_1 = jsPsych.data.getLastTimelineData().select('response').subset(function(x){ return x == 1; });
        // is it actually called stimulus?
        var image_data_ff_fs = jsPsych.data.getLastTimelineData().select('stimulus').subset(function(x){ return x = image_data.includes('ff' || 'fs')});
        var image_data_ff_fs = jsPsych.data.getLastTimelineData().select('stimulus').subset(function(x){ return x = image_data.includes('ss' || 'sf')});
        if (response_data_0 && image_data_ff_fs) {
            money.push(0.05)
        }
        else if (response_data_1 && image_data_ff_fs) {
            money.push(0)
        }
        else if (response_data_1 && image_data_ss_sf) {
            money.push(0.05)
        }
        else if (response_data_0 && image_data_ss_sf) {
            money.push(0)
        }
    }


    /* test procedure */
    var test_procedure = {
        timeline: [test, if_node, countFunction()],
        timeline_variables: test_stimuli,
        randomize_order: true
    };
    timeline.push(test_procedure);

[becky-gilbert]

Hi @mcd710, for (1), you're getting the error because you can't put a function on the timeline - everything in the timeline array should be an object. To run your countFunction at that point in the timeline, you can either call the function (a) from inside the conditional function in your if_node (after your existing code but before the return statements), or (b) using the call-function plugin. That should answer (2) as well.

For (3), I don't think what you have is quite right so I've suggested something else below. But I haven't tested this so it might not work. So to check, I've added statements to print out the values to the browser's JavaScript console.

var image_data_ff_fs = jsPsych.data.getLastTimelineData().select('stimulus').subset(function(x){ 
  console.log('stimulus: ', x);
  console.log('includes ff or fs: ', x.includes('ff') || x.includes('fs'));
  return x.includes('ff') || x.includes('fs');
});
console.log('image data ff fs: ', image_data_ff_fs);

I hope this helps! Can you let us know if these solutions work for you?

[mcd710]

Thanks so much for your response! It makes a lot of sense. I included your edits and I tried using the call-function plugin, but I keep getting the error Uncaught ReferenceError: jsPsychCallFunction is not defined.

Is there something wrong with the way I'm implementing it? Could it be to do with the fact that my function has arguments? Sorry if there's an obvious error I'm missing!

    /* get data from last trial and add to bonuses */
    var countFunction = function() {
        var response_data_0 = jsPsych.data.getLastTimelineData().select('response').subset(function(x){ return x == 0; });
        var response_data_1 = jsPsych.data.getLastTimelineData().select('response').subset(function(x){ return x == 1; });
        // images that contain either ff or fs
        var image_data_ff_fs = jsPsych.data.getLastTimelineData().select('stimulus').subset(function(x){ 
            console.log('stimulus: ', x);
            console.log('includes ff or fs: ', x.includes('ff') || x.includes('fs'));
            return x.includes('ff') || x.includes('fs');
            console.log('image data ff fs: ', image_data_ff_fs);
            });
        // images that contain either ss or sf
        var image_data_ss_sf = jsPsych.data.getLastTimelineData().select('stimulus').subset(function(x){ 
            console.log('stimulus: ', x);
            console.log('includes ss or sf: ', x.includes('ss') || x.includes('sf'));
            return x.includes('ss') || x.includes('sf');
            console.log('image data ss sf: ', image_data_ss_sf);
            });
        if (response_data_0 && image_data_ff_fs) {
            money.push(0.05)
        }
        else if (response_data_1 && image_data_ff_fs) {
            money.push(0)
        }
        else if (response_data_1 && image_data_ss_sf) {
            money.push(0.05)
        }
        else if (response_data_0 && image_data_ss_sf) {
            money.push(0)
        }
    }

    var countingTrial = {
        type: jsPsychCallFunction,
        func: countFunction
    }


    /* test procedure */
    var test_procedure = {
        timeline: [test, if_node, countingTrial],
        timeline_variables: test_stimuli,
        randomize_order: true
    };
    timeline.push(test_procedure);

    console.log(money)

[becky-gilbert]

Hi @mcd710, that error suggests that the plugin file isn't loaded. Did you remember to add the call-function plugin to the scripts that you load in the head section of your HTML file? Or maybe there's a typo in that line?

[mcd710]

Oh my gosh, of course! Silly mistake. Thank you so much, everything works now!! :)