How to show results to participants?

[ler93]

Hi all. I would like to show to participants the percentage of correct answers at the end of their performance in a raven test. Is there any way to do it? Any reference link?

Thanks!!

[becky-gilbert]

Hi @ler93, have you seen the example of this in the "data aggregation" step of the jsPsych simple RT task tutorial? The trick is to use a dynamic parameter to present the percentage correct text to the participant (since this is information that you don't know in advance and need to generate during the experiment) and to use the jsPsych data manipulation functions inside your dynamic parameter function to get the trials you want to summarize and calculate the performance measures.

I hope that helps. Let us know if you get stuck on this and need any further guidance.

[ler93]

Hi, @becky-gilbert! I don't know why it doesn't return a numerical data at the end of the experiment (says "You answered correctly in NaN% of responses..."). I copy part of the code below:

var timeline = [];

     var raven35 = {
       type: 'image-button-response',
       choices: 'Raven35_complete.png',
       options: ['1', '2', '3', '4', '5', '6', '7', '8'],
       task: 'raven',
       correct_response: '1'
     };
     timeline.push (raven35);
     
     var show_results = {
       type: 'html-keyboard-response',
       stimulus: function () {
         var trials = jsPsych.data.get(). filter ({task: 'raven'});
         var correct_trials = trial.filter ({correct: true});
         var accuracy = Math.round (correct_trials.count() / trial.count() * 100);
         
         return `<p> You answered correctly in $ {accuracy}% of the trials. </p>
         <p> Press any key to end the experiment. Thanks! </p> `;
       }
     };
     timeline.push (show_results);
     
 jsPsych.init ({
 timeline: timeline,
 });

Maybe there is an error in the code but I can't figure out what it is.

[becky-gilbert]

Ah, it looks like you're missing a few steps here. Specifically, the way that you've added task: raven and correct_response: '1' to the raven35 trial won't work, because those things need to go inside the trial's data parameter. Also, you'll need to score each raven response as correct or incorrect when the trial is finished, which you can do in the trial's on_finish function. Have a look at part 11 and part 12 of the simple RT task tutorial to see how to do these things.

Your raven trials will end up looking something like this:

var raven35 = {
  type: 'image-button-response',
  stimulus: 'Raven35_complete.png',
  choices: ['1', '2', '3', '4', '5', '6', '7', '8'],
  data: {
    task: 'raven',
    correct_response: '1'
  },
  on_finish: function(data) {
    // the value of "response" in the data will be the index of the button that was clicked, starting with 0
    // so we need to compare that number to the index of the correct response in the choices array ('1' = index 0, '2' = index 1, etc.)
    // if the two indices are the same, then "correct" will be true, otherwise it'll be false
    data.correct = data.response == ['1', '2', '3', '4', '5', '6', '7', '8'].indexOf(data.correct_response);
  }
};

(BTW I noticed some incorrect parameter names in the code you posted, so I've changed those above).

Your show_results trial looks good. The only thing there is that your set of raven trials is called trials, but then you switch to calling it trial.

Also, if you want to check the values of your variables like trials, correct_trials, etc. you can put some console.logs inside the stimulus function, which will print the values to the browser's JavaScript console. This is useful for debugging problems. I've added some examples below.

var show_results = {
  type: 'html-keyboard-response',
  stimulus: function () {
    var trials = jsPsych.data.get().filter({task: 'raven'});
    console.log('trials: ',trials); // this should print the data from all raven trials
    console.log('trial count: ', trials.count());  // this should print the total number of trials
    var correct_trials = trials.filter({correct: true});
    console.log('correct trial count: ', correct_trials.count());  // this should print the number of correct trials
    var accuracy = Math.round((correct_trials.count() / trials.count()) * 100);
    return `<p>You answered correctly in ${accuracy}% of the trials.</p>
         <p>Press any key to end the experiment. Thanks!</p> `;
  }
};

I hope this helps! Let us know if you get it working or run into any other problems.

[ler93]

Becky! It worked perfectly! Thank you so much for your help!! :)