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The Fusion mobile app supports running jsPsych experiments directly on participants’ phones and tablets. Experiments render in a WebView with automatic orientation handling and local-first data storage.

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How It Works

  1. Participant opens the quest in the Fusion mobile app
  2. Taps on an experiment card to start
  3. The experiment loads in a full-screen WebView
  4. Screen locks to landscape orientation for the duration of the experiment
  5. When the experiment calls jatos.endStudy(data), the data is captured
  6. Screen returns to portrait orientation
  7. A completion alert shows the number of trials recorded

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Data Flow

Data is saved locally first, so experiment data is not lost if the participant loses connectivity during or after the experiment. It syncs to the server automatically when a connection is available.

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Differences from Web

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Export on Mobile

Participants can export their experiment data directly from the mobile app:
  1. Navigate to the completed experiment
  2. Use the export option
  3. Data is saved as a JSON file and shared via the device’s share sheet (AirDrop, email, Files, etc.)
This uses expo-file-system and expo-sharing under the hood.

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When to Use Mobile vs. Web

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Tips

Design your experiment layout to work well in landscape orientation on phone-sized screens. Test on actual devices before launching.
  • Experiments run on both iOS and Android through the Fusion app
  • The same experiment code works on both web and mobile — no separate version needed
  • Mobile data is tagged with source mobile so you can distinguish it from web data in your analysis
  • If your experiment uses touch input instead of keyboard, it will work naturally on mobile
  • Benign CORS “Script error.” messages are automatically filtered on mobile