Apple's Latest Machine Learning Journal Entry Focuses on 'Hey Siri' Trigger Phrase

Apple's latest entry in its online Machine Learning Journal focuses on the personalization process that users partake in when activating "Hey Siri" features on iOS devices. Across all Apple products, "Hey Siri" invokes the company's AI assistant, and can be followed up by questions like "How is the weather?" or "Message Dad I'm on my way."

"Hey Siri" was introduced in iOS 8 on the iPhone 6, and at that time it could only be used while the iPhone was charging. Afterwards, the trigger phrase could be used at all times thanks to a low-power and always-on processor that fueled the iPhone and iPad's ability to continuously listen for "Hey Siri."

hey siri iphone x
In the new Machine Learning Journal entry, Apple's Siri team breaks down its technical approach to the development of a "speaker recognition system." The team created deep neural networks and "set the stage for improvements" in future iterations of Siri, all motivated by the goal of creating "on-device personalization" for users.

Apple's team says that "Hey Siri" as a phrase was chosen because of its "natural" phrasing, and described three scenarios where unintended activations prove troubling for "Hey Siri" functionality. These include "when the primary users says a similar phrase," "when other users say "Hey Siri"," and "when other users say a similar phrase." According to the team, the last scenario is "the most annoying false activation of all."

To lessen these accidental activations of Siri, Apple leverages techniques from the field of speaker recognition. Importantly, the Siri team says that it is focused on "who is speaking" and less on "what was spoken."

The overall goal of speaker recognition (SR) is to ascertain the identity of a person using his or her voice. We are interested in “who is speaking,” as opposed to the problem of speech recognition, which aims to ascertain “what was spoken.” SR performed using a phrase known a priori, such as “Hey Siri,” is often referred to as text-dependent SR; otherwise, the problem is known as text-independent SR.

The journal entry then goes into how users enroll in a personalized "Hey Siri" process using explicit and implicit enrollment. Explicit begins the minute that users speak the trigger phrase a few times, but implicit is "created over a period of time" and made during "real-world situations."

The Siri team says that the remaining challenges faced by speaker recognition is figuring out how to get quality performance in reverberant (large room) and noisy (car) environments. You can check out the full Machine Learning Journal entry on "Hey Siri" right here.

Since it began last summer, Apple has shared numerous entries in its Machine Learning Journal about complex topics, which have already included "Hey Siri", face detection, and more. All past entries can be seen on Apple.com.

Top Rated Comments

ThatGuyInLa Avatar
48 months ago
Apple can post all the journals and blog entries they want. Siri sucks. (When compared to others)

As I’ve said before, they need to fire the entire team and hire new. Poach if needed. They need to JOBS THIS SOB.
Score: 8 Votes (Like | Disagree)
barkomatic Avatar
48 months ago
Blah blah blah, neural networks, blah blah blah, set the stage for improvements, blah. They need to actually *make* those improvements and quickly. Either that or allow us to use Google assistant or Alexa natively on the iPhone. I'm tired of Siri telling me about web searches. It's hard to believe how Apple dropped the ball that they brought to the game.
Score: 6 Votes (Like | Disagree)
WWPD Avatar
48 months ago
I thought they did say 'Computer' often before issuing commands in Star Trek? Maybe my memory is fuzzy though.
Computer was always the trigger word in Star Trek.
Score: 3 Votes (Like | Disagree)
sundog925 Avatar
48 months ago
They're whole siri system needs an overhaul.
Its lagging so far behind others, dictation is awful, through bluetooth is worse. its just all around poor.

Even spotify's new voice control is lightyears more accurate than siri :rolleyes:
Score: 3 Votes (Like | Disagree)
TheBruno Avatar
48 months ago
I had to disable this trigger. I can't say 'serious' anywhere in the vicinity of my iPad Pro.
Score: 2 Votes (Like | Disagree)
iamgalt Avatar
48 months ago
I can't say I've experienced too many unintended activations, but I do still wish apple would allow us to change the triggering phrase to whatever we wanted. That may help with unintended activations for each person.
Score: 2 Votes (Like | Disagree)

Popular Stories

macbook pro 13 inch banner

Apple Planning Five New Macs for 2022, Including Entry-Level MacBook Pro Refresh

Sunday December 5, 2021 7:55 am PST by
Apple is working on five new Macs for launch in 2022, including a new version of the entry-level MacBook Pro, according to Bloomberg's Mark Gurman. In the latest edition of his "Power On" newsletter, Gurman said that he expects Apple to launch five new Macs in 2022, including: A high-end iMac with Apple silicon to sit above the 24-inch iMac in the lineup A significant MacBook Air...
apple watch series 7 aluminum colors

2022 Apple Watch Lineup Rumored to Include New Apple Watch SE and 'Rugged' Model for Sports

Sunday December 5, 2021 8:22 am PST by
Apple is planning an entire revamp of its Apple Watch lineup for 2022, including an update to the Apple Watch SE and a new Apple Watch with a rugged design aimed at sports athletes, according to respected Bloomberg journalist Mark Gurman. Writing in the latest installment of his Power On newsletter, Gurman said that for 2022, alongside the Apple Watch Series 8, Apple is planning an update to ...
airtag in hand

Apple AirTag Linked to Increasing Number of Car Thefts, Canadian Police Report

Friday December 3, 2021 7:10 am PST by
Apple's AirTags are being used in an increasing number of targeted car thefts in Canada, according to local police. Outlined in a news release from York Regional Police, investigators have identified a new method being used by thieves to track down and steal high-end vehicles that takes advantage of the AirTag's location tracking capabilities. While the method of stealing the cars is largely ...
1x 1

Apple CEO Tim Cook 'Secretly' Signed $275 Billion Deal With China in 2016

Tuesday December 7, 2021 6:49 am PST by
Apple CEO Tim Cook "secretly" signed an agreement worth more than $275 billion with Chinese officials, promising that Apple would help to develop China's economy and technological capabilities, The Information reports. In an extensive paywalled report based on interviews and purported internal Apple documents, The Information revealed that Tim Cook personally forged a five-year agreement...
ipad air arrive feature

iPad Pro With Wireless Charging, iPad Air 5, and iPad 10 Reported to Debut in 2022

Sunday December 5, 2021 8:54 am PST by
Apple is preparing to update three of its iPad models in 2022, including the entry-level iPad, iPad Air, and iPad Pro, according to Bloomberg's Mark Gurman. In his latest "Power On" newsletter, Gurman reiterated Apple's plans to release a new iPad Pro in 2022, featuring a new design and wireless charging, and clarified the company's intention to release new versions of the entry-level iPad...
2021 MBP SD Card Error Feature

Some SD Cards Not Working Properly With 2021 14 and 16-Inch MacBook Pros

Monday December 6, 2021 2:02 pm PST by
The SD card reader slot on the new 14 and 16-inch MacBook Pro models is not functioning as expected with some SD cards, according to multiple reports on the MacRumors forums. In a long complaint thread, MacRumors readers have detailed the issues that they're having with some SD cards, and there seems to be little consistency between reports and affected SD cards. Some SD cards crash and...
airpods pro blue holiday 3

Deals: AirPods Pro With MagSafe Available for $169.99 and Christmas Delivery on Amazon ($79 Off) [Update: Expired]

Monday December 6, 2021 6:03 am PST by
Amazon today has Apple's AirPods Pro with MagSafe Charging Case for $169.99 and delivery before Christmas Day, down from an original price of $249.00. This is $10 off from the rock bottom $159.99 price tag we tracked on Black Friday and Cyber Monday, and still a great deal for anyone shopping this holiday season. Note: MacRumors is an affiliate partner with Amazon. When you click a link and...
life360 app

Tile Buyer Life360 Selling Precise Location Data on Millions of Users

Monday December 6, 2021 1:05 pm PST by
Location tracking service Life360 has been selling the precise location data of tens of millions of its users, according to a new report shared by The Markup. Life360 bills itself as a "family safety platform" app that is meant to allow family members to keep tabs on one another with tracking software that's installed on smartphones, and there are both Android and iPhone apps. The...