Skip to main content
Version: 3.9.x

PsychoPy and JATOS

How to turn a PsychoPy experiment into a JATOS study - Either watch the video or follow the instructions.

Create a Study in JATOS​

  1. Open JATOS in your browser. (Need to install JATOS locally? Find out how here).
  2. Create a new study: Click on Studies to open the sidebar, then select +, and finally New Study.
  3. JATOS will create a new study and display its study page. Make a note of the study assets folder name; you'll need it later. You can find it at the top of your study page. By default, it will look similar to 0413af8c-8512-4105-b89b-08a7f557cb57.
  4. Add a new component: Click the New Component button. In the window that appears, enter a title (this is up to you) and type index.html into the 'HTML file path' field. Then, press Add.

Adapt Your PsychoPy Experiment to JATOS​

Now, let's configure PsychoPy/PsychoJS to save your experiment's result data directly to JATOS.

  1. Obtain your PsychoPy experiment (for example, you can download it from https://pavlovia.org/explore).

  2. Copy the contents of your PsychoPy experiment folder into the study assets folder you created in JATOS. By default, this folder is located in your JATOS installation directory under study_assets_root.

  3. Open the copied experiment (the one now within the JATOS study asset folder) in the PsychoPy Builder.

  4. Select the last routine of your experiment and add a custom code component (found under Components -> Custom -> Code).

  5. In the new code properties window, change the 'Code type' to 'JS' since we'll be adding JavaScript.

  6. Open 'Before experiment' and add the following line:

    jQuery.getScript("jatos.js");

    This line loads the jatos.js library.

  7. Open 'Begin experiment' and add the following line:

    psychoJS._saveResults = 0;

    This instructs PsychoJS not to save the result data locally.

  8. Open 'Begin Routine' and add the following lines:

    const data = psychoJS._experiment._trialsData;

    jatos.submitResultData(data);

    This sends the result data in JSON format to JATOS at the end of the experiment.

    If you prefer CSV format:

    const data = psychoJS._experiment._trialsData;

    const dataCsv = data.map(it => Object.values(it).join(',')).join('\n')
    jatos.submitResultData(dataCsv);

  9. Open 'End experiment' and add the following line:

    jatos.startNextComponent();

    This ends the current component in JATOS and either starts the next one (if you have multiple components) or finishes the study.

  10. Close the code properties window by clicking OK.

  11. Save your experiment in the PsychoPy Builder.

  12. Switch to the PsychoPy Runner.

  13. Generate the browser version of your experiment by selecting Run then Run JS for local debug from the top menu. This action will add your experiment's JavaScript file and a new 'lib' folder (containing PsychoJS JavaScript and CSS files) to your experiment folder. It will also open a browser tab, which you can close as you'll be running the experiment within JATOS.

  14. Navigate to your study page in JATOS (the one you created earlier) and click Run.

  15. If everything is set up correctly, your experiment should now be displayed.

  16. Check that, after your study has finished, the result data are available in JATOS: go to your study page, then click Results, and finally expand the first result by clicking ▼ in the first column.

  17. At this point, you can export or import your study to another JATOS instance.

Note: In some PsychoPy experiments, you need to add a keyboard response component with the 'Force end of routine' checkbox activated at the end of the last routine of the experiment to ensure that JATOS properly finishes the study.