counting backward with conditionals

[LeslieHeld]

Hello!

I have a question concerning the jsPsych.data.get().last(x).values()[0].xy command. Namely, I'm running an experiment with a timeline including conditional statements.

In the main block the timeline is [loop_node,target,correct_conditional,points_conditional] (with loop_node looping over [fixation, activation conditional] until participants activate the fixation screen with the correct button). In the baseline block the timeline is [loop_node,target,correct_conditional] (hence the same without points_conditional).

If correct_conditional or points_conditional evaluate true, participants will receive feedback on their correctness or points respectively.

At each fixation in the loop_node, I want to count back to the last fixation (or target) in order to receive a choice parameter. The problem is that depending on the conditionals evaluating false or true and the phase of the experiment (main block/baseline), I have to count back 2, 3 or 4 times.

I also tried to use jsPsych.data.getLastTrialData().values()[0].choice instead but that does not seem to work in the on_finish() part of my timeline variable.

Do you have an idea on how I can fix this?

Thanks a lot in advance!

[jodeleeuw]

Hi @LeslieHeld,

I recommend using the data parameter to tag the choice trial with some kind of unique identifier and then use the .filter() method when you want to grab the data.

var choice = {
	data: {phase: 'choice'}
}

var loop_node = {
	loop_function: function(){
		jsPsych.data.get().filter({phase: 'choice'}).values()[0].choice
	}
}

I'm not quite sure which on_finish you are referring to in the second part of your question.

[Nega100]

Hi! @jodeleeuw @LeslieHeld and all JsPsych Contributors!,
I think I have the same problem. I created n-back and implemented conditional timeline. I intended to measure the proportion in corect answer and after a few trials decided the conditional to end experiment/other feedback. However the conditional timeline seems not run properly. I dont understand what I missed. The correct answer is below 0.6 but the message not showing up, instead showing in the end of trials. Thanks for the answer!!

    var cons_end_2 = {
      type: 'html-keyboard-response',
      stimulus: '<p>Too many error!</p>',
      choices: jsPsych.NO_KEYS,
      trial_duration: 5000
    };
    var conditional_2 = {
        timeline: [cons_end_2],
        conditional_function: function() {
            var two_back_cond = jsPsych.data.get().filter({even:'2-back'}).last(nback_length-2);
            var two_back_correct = two_back_cond.filter({correct: true}).count();
            var prop_tab_correct = two_back_correct/(nback_length-2)
            if (prop_tab_correct < 0.6) {
                return true;
            } else {
                return false;
            }
        }
    };
    timeline.push(conditional_2)

[jodeleeuw]

Hi @Nega100,

This code looks OK to me at first glance. Any error messages? Have you tried using the debugging tools to see what the value of the variables are in the conditional_function?

[Nega100]

Thanks Josh!. I will try look more detailed what really happening in my code. There are no error messages and in console.log() the result came out as I expected. If you have other debugging tools I'd very appreciated. Thanks a lot for the fast reply!

[jodeleeuw]

Hi @Nega100 ,

Web browsers have a great set of debugging tools built into them. Here's an overview of how to debug in Chrome, and the process is very similar in other browsers.