Change_attr

[kittymimo]

Hi,

I'm having trouble with the "change_attr" property. I would like to provide feedback, such that a check mark is shown when the answer is correct and an X mark is shown when the answer is incorrect. I also want to provide the correct sound and picture at the same time. Everything is working except that when I get a correct answer, I see an X mark instead of a check mark. I think this line is incorrect but I don't know how to correct it: stim.file = jsPsych.timelineVariable('crochet'). Bellow is the full script for this variable.

Thanks for your help!

Catherine

    var retroaction = {
        timeline: [
            {
                type: 'psychophysics',
                stimuli: [
                    {
                        obj_type: 'sound',
                        file: jsPsych.timelineVariable('phrase')
                    },
                    {
                        obj_type: 'image',
                        file: jsPsych.timelineVariable('bonne_reponse'),
                        startX: 625
                    },
                    {
                        obj_type: 'image',
                        file: jsPsych.timelineVariable('x'),
                        startX: 200,
                        change_attr: function(stim) {
                            if (jsPsych.data.getLastTrialData().values()[0].accuracy == true) {
                                stim.file = jsPsych.timelineVariable('crochet')
                            }
                        }
                    },
                ],
                background_color: "FFFFFF",
                choices: jsPsych.NO_KEYS,
                trial_duration: 4000

            }
        ]
    }

[kurokida]

Thank you for using my plugin. I noticed from your question that the change_attr function doesn't allow you to change all the attributes. I would like to apologize for this.

So, I propose to divide the trial into two parts, that is, one is for presenting the stimulus and the other is for providing the feed back.

Here is the sample code:

    const images = [ // All the images used in this demo
        './img/scissors.png',
        './img/pen.png',
        './img/battery.png'
    ];

    const present_stim =  {
        type: 'psychophysics',
        stimuli: [
            {
                obj_type: 'cross', // fixation
                line_length: 20, // pixels
                line_width: 4
            },
            {
                obj_type: 'image',
                file: jsPsych.timelineVariable('fileName'),
                show_start_time: 500 // ms after the start of the trial
            }
        ],
        response_type: 'key',
        choices: ['f', 'j'],
        canvas_height: 500,
        prompt: 'Press the F or J key.',
        data: {'file_name': jsPsych.timelineVariable('fileName')} // for identification
    }

    const feed_back = {
        type: 'image-keyboard-response',
        stimulus: './img/correct.png',
        choices: jsPsych.NO_KEYS,
        trial_duration: 1000,
        on_start(trial){
            console.log(trial)
            const resp = jsPsych.data.getLastTrialData().values()[0].key_press;
            if (jsPsych.pluginAPI.compareKeys(resp, 'j')) {
                console.log('Incorrect!')
                trial.stimulus = './img/incorrect.png'
            }
        }
    }

    var trial = {
        timeline: [present_stim, feed_back],
        timeline_variables: [
            {fileName: images[0]},
            {fileName: images[1]},
            {fileName: images[2]}
        ],
        randomize_order: true
    }

    jsPsych.init({
        timeline: [trial],
        preload_images: images, // The image data should be preloaded.
        on_finish: function(){jsPsych.data.displayData();}
    });

[kurokida]

A similar method is also available as follows.

    const correct_feed_back = {
        obj_type: 'image',
        file: './img/correct.png'
    }

    const feed_back = {
        type: 'psychophysics',
        stimuli: [correct_feed_back],
        choices: jsPsych.NO_KEYS,
        prompt: 'Feed back.',
        canvas_height: 500,
        trial_duration: 1000,
        on_start(trial){
            const resp = jsPsych.data.getLastTrialData().values()[0].key_press;
            if (jsPsych.pluginAPI.compareKeys(resp, 'j')) {
                console.log('Incorrect!')
                trial.stimuli[0].file = './img/incorrect.png';
            }
        }
    }

[kittymimo]

Thank you for your plugin and your answers; there's no need to apologize :)

Using "on_start" solved my problem, thank you!