​
Step 1. Setup Tracker

The Alias tracker integrates with JsPsych survey-text trials to identify potential fraudelent, inattentive, or bot-like responses to open-ended questions. You can use this as a naturalistic captcha to identify participants to exclude from your analyses. The API also does digital fingerprinting for additional security and duplicate detection.

The extension generates arrays of all the change events to open-ended questions (the “question histories”) as well as a fingerprint id, both of which you pass to our API. To use it:

  1. Add a link to it in index.html
  2. Include it in the initJsPsych call
  3. Pass it as an extension to any jsPsychSurveyText questions you want to track (you must include at least one survey-text question with our extension) The Alias tracker takes an optional initialization argument max_n_characters, when specifies the max number of characters the JSON string of each question_history can be (by default, this is 50,000; we highly recommend setting it to at least 20,000). The extension also requires a page_id parameter on every trial where the extension is used. This allows you to easily compare responses across participants even if there are conditional timelines or repeated questions.

We include a full example of using our extension in a JsPsych experiment in the public/ directory of our GitHub repository. Here’s a simplified example:

const jsPsych = initJsPsych({
  extensions: [
    { type: jsPsychAliasTracker, params: { max_n_characters:55000 } }
  ],
});

...

const openEndsTrial = {
  type: jsPsychSurveyText,
  questions: [
    { prompt: 'What do you think was the purpose of this experiment?', required: true, rows: 6 },
  ],
  extensions: [
    { type: jsPsychAliasTracker, params: { page_id:'page1' } }
  ]
}

...

​
Step 2. Call the API

Our tracker adds all data the Alias API needs to trial data with the jsPsychAliasTracker extension, stored as alias_questions, alias_responses, alias_question_histories, and alias_fingerprint_id. This data can be passed to our API without any further modifications. See an example in call-api.py.

​
Step 3. Deploy on Heroku

Deploy an Alias JsPsych experiment to Heroku, a cloud platform service.

git clone https://github.com/roundtableAI/alias-tracker.git  # Clones the repository
cd alias-tracker/                                            # Navigates into the directory
npm install                                                  # Installs all dependencies
heroku create your-app-name                                  # Creates a new Heroku app
git push heroku master                                       # Deploys the app to Heroku
heroku open                                                  # Opens the app in a web browser
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