NORTH READING, Mass. — Every day is graduation day at Amazon Robotics.

Here’s where the more than 100,000 orange robots that glide along the floors of various Amazon warehouses are made and taught their first steps.

Here they practice their first pirouettes. And heavy lifting too, as they twirl while hauling fabric shelves filled with cinder blocks.

And finally — once they’ve been given the green light by their makers — about 38 robots assemble in a tight four-row formation and in orderly fashion wheel themselves up onto pallets that will be shipped to one of the 25 Amazon warehouses that employ automatons.

Amazon staffers call it the “graduation ceremony,” and it takes place several times a day. “It’s a proud-mama moment,” an Amazon spokeswoman said, during the first visit to the facility by a reporter since the e-commerce giant bought the former Kiva Systems in 2012. So far this year the company has graduated more than 55,000 robots.

These robots, and the thousands of Amazonians who build, program and use them, are laying out the next episode in a very old story — the evolving relationship between humans and their tools.

From the sharp stones wielded by our early ancestors to the internet, every step along the way has awakened new possibilities, and new fears too.

Now, it’s the turn of robotics, a discipline that after decades of experimentation and recent big leaps in artificial intelligence has finally reached a maturity that allows mass deployment.

“We’re at an inflection point — the ability of robots to be useful at a low-cost point,” said Beth Marcus, a robotics expert and startup founder who recently joined Amazon Robotics as a senior principal technologist.

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This latest wave of automation has spurred anxiety among scholars and policymakers. They warn it might contribute to a growing economic divide, in which workers with more education or the right skills reap the benefits of automation, while those with inadequate training are replaced by robots and increasingly left out of lucrative jobs. It’s not a novel concern: Spinning jennies, which revolutionized the weaving industry, sparked similar resistance in 19th century England. And in the 1960s, the U.S. government created a task force to study the impact of technology on livelihoods. “If we understand it, if we plan for it, if we apply it well, automation will not be a job destroyer or a family displaced,” President Lyndon Johnson said at the time.

History has shown that, over time, job losses in rapidly advancing sectors are offset by gains in other activities spurred by a growing economy.

That perspective doesn’t quell contemporary concerns. Microsoft co-founder Bill Gates has proposed taxing robots to pay for other jobs, such as teachers. Some scholars also seem to be losing faith in the old playbook.

“There’s never been a worse time to be a worker with only ‘ordinary’ skills and abilities to offer, because computers, robots and other digital technologies are acquiring these skills and abilities at an extraordinary rate,” Massachusetts Institute of Technology professors Erik Brynjolfsson and Andrew McAfee wrote in their 2014 book, “The Second Machine Age.”

In a recent report, the Organization for Economic Cooperation and Development said that technology is contributing to the disappearance of middle-skill jobs, both in manufacturing and in clerical work, even though it helps create both highly skilled and low skilled positions.

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Amazon is the modern poster child for automation, and not only because of the orange warehouse robots. Its machine-learning software lets the company predict customer behavior. New retail concepts, such as the Amazon Go convenience store in downtown Seattle, heavily rely on sensor technology in an effort to do away with the need for cashiers.

Amazon is also working hard to have drones deliver items to people’s homes, a move that may replace a lot of delivery drivers.

But automation certainly hasn’t slowed down Amazon’s colossal appetite for people. The company’s payroll expansion has long exceeded revenue growth: In the quarter that ended last June, its workforce grew by 42 percent to 382,400 jobs, versus sales growth of 25 percent.

It’s hard to say, in the case of Amazon, how many potential human jobs have gone to the robots, or inversely, how many new positions have been created to handle this new feature of working life.

But Amazon says that warehouses equipped with robotics typically see “greater job creation with more full-time employees,” due to the increased volume of orders these centers can handle. Amazon also says automation has meant the creation of desirable, high-skilled jobs designing robots and teaching them how to do things, as well as middle-skilled jobs such as repairing the robots, or simply focusing on more sophisticated warehouse tasks while letting machines do the boring stuff.

Marcus says that there are plenty of tasks humans will monopolize for a long time.

“There are many things humans do really well that we don’t even understand yet,” Marcus said.

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Amazon Robotics’ facility, in suburban Boston, was first established by Kiva Systems, a company founded on the concept of flipping warehouse logistics around. Instead of having workers walk to products, it sought to bring items to the workers. The solution: flat, wheeled robots called “drive units” that navigate a warehouse by reading stickers on the floor, all while carrying merchandise on their back.

Amazon bought Kiva in 2012 for $775 million in cash and started introducing the robots into its warehouses in 2014.

Since then, the robotics facility stopped selling to other customers, while its orange robots, now in their fourth generation, have come to play an important part in Amazon’s operations. In fact, robotics seem to be more important to Amazon’s bottom line than to other tech giants also making big bets in the field, such as Google, experts say.

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A few steps into the Amazon Robotics building, a small sign warns visitors — in jest — to please not feed the robots.

Some 500 employees work in the facility, mostly engineers and scientists, as well as technicians who assemble the robots. The hardware side is led by Parris Wellman. As a kid he wanted to build cars and went on to earn a mechanical-engineering degree at the University of Pennsylvania. There, studying under prominent roboticist Vijay Kumar, Wellman discovered robots. After a Ph.D. from Harvard and a few years in biotech and in medical devices, he joined Amazon Robotics, returning to what he calls his “first love.”

What he likes about the opportunity is that he can build something and deploy it en masse pretty quickly.

Another interesting aspect of the work, he said, is that the roboticists get plenty of feedback from the warehouse associates who will be dealing directly with the robots. For example, associates helped designers pick out the color of the new lightweight fabric shelves that the robots carry: yellow, because that makes it easier to see the items they carry.

And it was a maintenance worker at a warehouse who designed, and patented with Amazon’s help, a metal rod that staffers use to push inactive robots around the factory floor (it’s easier than picking up the 750-pound robots).

“Innovation is not restricted to a particular set of people,” Wellman said.

In addition to hardware engineers, the facility employs software developers who animate the drive units throughout the Amazon empire. “People don’t realize Amazon Robotics has a huge software stack,” says Jill Sestini, a developer who was Kiva System’s 30th employee when she joined in 2006.

Brady, the Amazon Robotics’ chief technologist, says the roboticists’ efforts have brought a more than 50 percent increase in storage efficiency at the Amazon warehouses that employ robots. That means they can contain more items in a smaller space. These warehouses are also where Amazon figures out how people and machines can work together as in a “beautiful symphony,” according to Brady.