Your voice & audio data stays private while Google Assistant improves

Federated learning is a privacy-enhancing technique that helps us improve machine learning models without a need to send your raw data to Google servers. We use this technique to improve on-device models like “Hey Google” in Google Assistant.

When you ask, "Hey Google, what’s the weather tomorrow?" an on-device model detects that you said “Hey Google.” Then it sends your query to Google Assistant. This model might:

  • On rare occasions, misactivate, or trigger when you didn’t say “Hey Google.”
  • In other cases, miss, or not trigger, when you did say “Hey Google.”

We now use federated learning to refine this model and try to reduce misactivations and misses.

About your voice recordings

When Google Assistant activates or nearly activates, federated learning temporarily stores short bits of your voice recordings on your device. With federated learning, we use these recordings to learn how to adjust Google Assistant's triggering logic.

When Google Assistant activates

  • It sends your voice recording to Google so your Assistant can complete your request, like give you the weather forecast.
  • If you have Web & App Activity turned on and include audio recordings, Google stores your recordings on its servers.

When Google Assistant nearly activates

Near activations happen when the “Hey Google” model detects audio or something you say that almost activates Google Assistant.

Google servers don’t save your voice recordings from near activations, but your device does if federated learning is on. Your device may not indicate anything when it stores these recordings and may store up to 20 recordings per day, which includes:

  • Data about how and when you interact with your phone
  • How successful an interaction is
  • Information about your phone configuration

How long on-device recordings are kept

Federated learning keeps all on-device recordings it uses to improve the “Hey Google” model for no more than 63 days, unless you delete them before then. Learn how to delete your on-device recordings.
Learn how to turn federated learning on or off.

How Google Assistant improves with federated learning

Federated learning uses the voice recordings stored on users’ devices to refine models like “Hey Google.” It learns how to adjust the model from the voice data, and sends a summary of the model changes to Google servers. To provide a better model for everyone, these summaries are aggregated across users.

Federated learning performs computations on your device only when the device is idle, plugged in, and connected to Wi-Fi.

How federated learning protects your data

Federated learning doesn’t send or store your voice recordings on Google servers but instead:

  • Learns on your device.
  • Encrypts and stores your voice recordings on your device.
  • Deletes the recordings when it no longer needs them to improve the models.

Learn more from Google AI’s online comic.

Tip: To control whether Google servers store your voice recordings, go to Activity controls.

Manage federated learning & your data

By default, federated learning with the “Hey Google” model is turned off.

Turn on federated learning
  1. On your Android phone or tablet, say "Hey Google, open Assistant settings".
  2. Under “All settings,” tap Help improve Assistant. If you don't find the setting, first tap You.
  3. Turn on Improve Assistant.
Turn off federated learning & delete your on-device voice recordings
  1. On your Android phone or tablet, say "Hey Google, open Assistant settings".
  2. Under “All settings,” tap Help improve Assistant. If you don't find the setting, first tap You.
  3. Turn off Improve Assistant.

When you turn off federated learning

Delete your voice recordings from Google servers

In My Activity, you’ll find a list of your past activity on Google Assistant. If an activity includes a recording, it has an audio icon Speak.

  1. Go to your Google Assistant Activity in My Activity.
  2. Choose the activity you want to delete:
    • To delete a specific activity and recording: Next to the one you want to delete, select More More and then Delete.
    • To delete all Google Assistant activity, not just activity with a recording: At the top right, select More More and then Delete activity by and then All time.

Learn more about how to manage your audio recordings.

Don’t store your voice recordings on Google servers
  1. Go to your Activity controls.
  2. If Web & App Activity is turned on, uncheck the box next to "Include audio recordings."
    • When Web & App Activity is turned off or “Include audio recording” isn’t checked, Google doesn’t actively store your voice recordings

Learn more about Web & App Activity.

Turn off “Hey Google”
  1. On your Android phone or tablet, say "Hey Google, open Assistant settings" or go to Assistant settings.
  2. Under “All settings,” tap General.
  3. Turn off Google Assistant.
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