Giving feedback on answers

[marthaflinderslewis]

I would like to give feedback on participants' answers after they have completed the experiment. I am trying to do this by using the data that a participant has submitted as a set of timeline variables as below, but I get a type error that undefined is not an object. any ideas?

... trials where the experiment is run...
	var feedback = {
		type:jsPsychHtmlButtonResponse,
		stimulus: function() {
			var pt = jsPsych.timelineVariable('prob_type');
			var stim_string = 'Prob type: ' + pt; //placeholdr, just want to get it working
			return stim_string
		},
		choices: ['Continue']
	}

	var full_feedback = {
		timeline: [feedback],
		timeline_variables: jsPsych.data.get().last(4).values(),
		randomize_order: false,
		repetitions: 4,
	}
	timeline.push(full_feedback)

[jodeleeuw]

If you are using jsPsych version 8 then the timelineVariable call should be evaluateTimelineVariable. We made this more explicit when called inside a function instead of as a timeline level property.

[marthaflinderslewis]

Thank you for the quick response! I am using jsPsych 7.2.1 - is there a way to do it using this version?

[jodeleeuw]

Yes -- I think the issue is probably timeline_variables: jsPsych.data.get().last(4).values(). The problem here is that this code will run before the experiment starts (jsPsych.run() is later in the code). This is one of the most common jspsych mistakes. Unfortunately there's not currently a way to set timeline_variables after the experiment has started running, so you may need to approach this is a different way. Can you show more of the code from the trials that you want to give feedback on?

[marthaflinderslewis]

Sure: below is the code I am using for the actual experiment, this all works fine. I'd like to give feedback after all trials are completed

... 
variable all_problems imported from external file
setup  and instruction trials
...

        var all_prob_types = Object.keys(all_problems)
	var prob_order = Array.from({length: all_prob_types.length}, (x, i) => i)
	shuffle(prob_order)
	var chosen_prob_inds = prob_order.slice(0, 4)
	var attn1 = chosen_prob_inds[0]
	var attn2 = chosen_prob_inds[1]
	shuffle(chosen_prob_inds)
	var count = 0
	for (let j = 0; j < chosen_prob_inds.length; j++) {
		console.log(chosen_prob_inds[j])
		var current_prob = all_prob_types[chosen_prob_inds[j]]
		count++
		if ((chosen_prob_inds[j]==attn1) || (chosen_prob_inds[j]==attn2)) {
	                //attention check
			var gen = {
				type: jsPsychSurveyText,
				preamble:   '<p>Problem '+(count)+' of 12<\p>'+
							'<p>Try to guess the missing piece.<\p>',
				questions: [
					{
						prompt: "For this question, answer '@@@'", 
						columns: 42,
						name: 'attn_gen', 
						required: true
					}, 
				],
				on_finish: function(){
					var timestamp = (new Date).toISOString().replace(/z|t/gi,' ').trim();
					jsPsych.data.addDataToLastTrial({timestamp});
				}
			};
		}
		else {
			var gen = {
				type: jsPsychSurveyText,
				preamble:   '<p>Problem '+(count)+' of 12<\p>'+
							'<p>Try to guess the missing piece.<\p>',
				questions: [
					{
						prompt: jsPsych.timelineVariable('prompt'), 
						columns: 42,
						name: current_prob + '_gen', 
						required: true
					}, 
				],
				on_finish: function(){
					var timestamp = (new Date).toISOString().replace(/z|t/gi,' ').trim();
					jsPsych.data.addDataToLastTrial({timestamp});
				}
			};
		}

		var full_trial = {
			timeline: [gen],
			preamble: all_problems[current_prob],
			data: { 
					prob_type: current_prob,
					prob_ind: jsPsych.timelineVariable('prob_ind')},
			timeline_variables: all_problems[current_prob],
			sample: {
				type: 'without-replacement',
				size: 1
			}
		}
		timeline.push(full_trial)
	};