Machine teaching: How people’s expertise makes Ai even more powerful

REDMOND, WA Most people wouldn’t think to teach five-year-olds how to hit a baseball by handing them a bat and ball, telling them to toss the objects into the air in a zillion different combinations and hoping they figure out how the two things connect.

And yet, this is in some ways how we approach machine learning today — by showing machines a lot of data and expecting them to learn associations or find patterns on their own.

For many of the most common applications of AI technologies today, such as simple text or image recognition, this works extremely well.

But as the desire to use AI for more scenarios has grown, Microsoft scientists and product developers have pioneered a complementary approach called machine teaching. This relies on people’s expertise to break a problem into easier tasks and give machine learning models important clues about how to find a solution faster. It’s like teaching a child to hit a home run by first putting the ball on the tee, then tossing an underhand pitch and eventually moving on to fastballs.

“This feels very natural and intuitive when we talk about this in human terms but when we switch to machine learning, everybody’s mindset, whether they realize it or not, is ‘let’s just throw fastballs at the system,’” said Mark Hammond, Microsoft general manager for Business AI. “Machine teaching is a set of tools that helps you stop doing that.”

Machine teaching seeks to gain knowledge from people rather than extracting knowledge from data alone. A person who understands the task at hand — whether how to decide which department in a company should receive an incoming email or how to automatically position wind turbines to generate more energy — would first decompose that problem into smaller parts. Then they would provide a limited number of examples, or the equivalent of lesson plans, to help the machine learning algorithms solve it.

In supervised learning scenarios, machine teaching is particularly useful when little or no labeled training data exists for the machine learning algorithms because an industry or company’s needs are so specific.

Microsoft at Bowie State University

Microsoft’s team visited Bowie State University’s Computer Science students on April 16, 2019. (L-R) Jamal Blackwell, Imani McLaurin, and Christoper Stone. — BDPA-DC photo by Evan Carter ©2019 bdpatoday

In difficult and ambiguous reinforcement learning scenarios — where algorithms have trouble figuring out which of millions of possible actions it should take to master tasks in the physical world — machine teaching can dramatically shortcut the time it takes an intelligent agent to find the solution.

It’s also part of larger goal to enable a broader swath of people to use AI in more sophisticated ways. Machine teaching allows developers or subject matter experts with little AI expertise, such as lawyers, accountants, engineers, nurses or forklift operators, to impart important abstract concepts to an intelligent system, which then performs the machine learning mechanics in the background.

Microsoft researchers began exploring machine teaching principles nearly a decade ago, and those concepts are now working their way into products that help companies build everything from intelligent customer service bots to autonomous systems.

“Even the smartest AI will struggle by itself to learn how to do some of the deeply complex tasks that are common in the real world. So you need an approach like this, with people guiding AI systems to learn the things that we already know,” said Gurdeep Pall, Microsoft corporate vice president for Business AI. “Taking this turnkey AI and having non-experts use it to do much more complex tasks is really the sweet spot for machine teaching.”

Today, if we are trying to teach a machine learning algorithm to learn what a table is, we could easily find a dataset with pictures of tables, chairs and lamps that have been meticulously labeled. After exposing the algorithm to countless labeled examples, it learns to recognize a table’s characteristics.

But if you had to teach a person how to recognize a table, you’d probably start by explaining that it has four legs and a flat top. If you saw the person also putting chairs in that category, you’d further explain that a chair has a back and a table doesn’t. These abstractions and feedback loops are key to how people learn, and they can also augment traditional approaches to machine learning.

“If you can teach something to another person, you should be able to teach it to a machine using language that is very close to how humans learn,” said Patrice Simard, Microsoft distinguished engineer who pioneered the company’s machine teaching work for Microsoft Research. This month, his team moves to the Experiences and Devices group to continue this work and further integrate machine teaching with conversational AI offerings.

by Jennifer Langston | Cover photo: Microsoft




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