Simulation mode: survey-multi-select does not allow empty responses

[nikbpetrov]

Problem statement

The way the simulation mode for the survey-multi-select is set up is not only having the RT hard-coded (see line 343) but also does not account for cases where data.response might be empty.

E.g. say I have simulations options defined like so:

data: function () {
    const valid_responses_prop = 0.50
    if (jsPsych.randomization.sampleBernoulli(valid_responses_prop)) {
        return {rt: 100}
    } else {
        return {rt: null, response: null}
    }
}

where the expected output is that in 50% of the cases I get random responses (as generated by the plugin) after 100ms and in the other 50% of cases I would expect the response to be null.

2 issues:

1. If data.response is null, the simulate_visual errors when defining answers, line 322
2. if rt is null, there is no way to end the trial as this one does not support trial_duration

Solution

Apart from the fact that I don't quite understand why there is no trial_duration for this one, the solution I've implemented for myself is by first defining the simulation options like this:

data: function () {
    const valid_responses_prop = 0.50
    if (jsPsych.randomization.sampleBernoulli(valid_responses_prop)) {
        return {rt: 100}
    } else {
        return {rt: 100, response: null}
    }
}

(notice how the rt is 100 for both now)

and then check if data.response is null in simulate_visual function -- if it is, then we end the trial after data.rt (in this case, 100ms) using setTimeout, inside of which we call jsPsych.finishTrial(new_data), wherein new_data is the same as data but the rt is changed to be null

in code (notice that in my setup I've also got rid of the hardcoded 1000):

simulate_visual(trial, simulation_options, load_callback) {
    const data = this.create_simulation_data(trial, simulation_options);
    const display_element = this.jsPsych.getDisplayElement();
    this.trial(display_element, trial);
    load_callback();
    if (data.response != null) {
      const answers = Object.entries(data.response);
      for (let i = 0; i < answers.length; i++) {
          for (const a of answers[i][1]) {
              this.jsPsych.pluginAPI.clickTarget(display_element.querySelector(`#jspsych-survey-multi-select-response-${i}-${trial.questions[i].options.indexOf(a)}`), ((data.rt - data.rt) / answers.length) * (i + 1));
          }
      }
      this.jsPsych.pluginAPI.clickTarget(display_element.querySelector("#jspsych-survey-multi-select-next"), data.rt);
    } else {
      this.jsPsych.pluginAPI.setTimeout(() => {
          let new_data = _.merge(_.cloneDeep(data), {rt: null})
          this.jsPsych.finishTrial(new_data)
      }, data.rt)
    }
}