Your voice & audio data stays private while Google Assistant improves

Federated learning is a privacy-enhancing technology that we use to improve models on device without sending users’ raw data to Google servers. Google Assistant uses federated learning to improve “Hey Google.”

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

On rare occasions, this model might activate unintentionally, or trigger when you didn’t say “Hey Google.” In other cases, it might not trigger when you did say “Hey Google.”

We now use federated learning to refine the “Hey Google” model and try to reduce misactivations and misses.

Learn more about federated learning from Google AI’s online comic.

About your voice recordings

When “Improve Assistant's speech technologies” is on and Google Assistant activates or nearly activates, it 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

When Google Assistant activates, it may send your voice recording to Google so your Assistant can complete your request, like returning the weather forecast to your phone. These recordings are stored on Google servers if you have Web & App Activity turned on and include audio recordings.

When Google Assistant nearly activates

“Near activations” are cases when the “Hey Google” model detects audio, or something you said, that almost activated Google Assistant.

Your voice recordings from near activations aren’t sent to Google servers, but may be saved on your device if “Improve Assistant's speech technologies” is on. Your device may not indicate anything when it stores these recordings and may store up to 20 recordings per day, along with:

  • Data about how and when you interact with your phone
  • How successful an interaction was
  • Phone configuration information

How long on-device recordings are kept

On-device recordings from “Hey Google" activations and near-activations are kept on your device 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

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

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

How federated learning protects your data

When Google Assistant nearly activates, the voice recording isn't sent to Google servers. Instead, it may be stored on your device.

When Google Assistant activates, it may send your voice recording to Google servers so your Assistant can complete your request. In addition, it may be stored on your device.

When your voice recording is stored on your device, it's encrypted, used only to make improvements to the “Hey Google” model, and deleted when no longer needed, which is no more than 63 days.
 

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

Manage settings & your data

By default, the use of federated learning to improve the “Hey Google” model is turned off.

Turn on federated learning for the “Hey Google” model
  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 for the “Hey Google” model & 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 for the “Hey Google” model

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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