Would you like fries with that? McDonald’s already knows the answer

McDonald’s has a new plan to sell more Big Macs: act like Big Tech.

For seven months, McDonald’s has spent hundreds of millions of dollars to acquire technology companies that specialize in artificial intelligence and machine learning. And the fast-food chain has even established a tech hub in the heart of Silicon Valley — the McD Tech Labs — where a team of engineers and data scientists is working on voice-recognition software.

The goal? To turn McDonald’s, a chain better known for supersized portions than for supercomputers, into a saltier, greasier version of Amazon.

In recent years, fast-food sales have slowed across the United States, as Americans turn to healthier alternatives. While it has performed better than many of its rivals, McDonald’s has lost customers, closed restaurants and seen its quarterly sales dip below analysts’ expectations.

The chain’s new emphasis on technology is a bid to reverse that trend. So far, the technological advances can be experienced mostly at the company’s thousands of drive-thrus, where for years menu boards have displayed a familiar array of McDonald’s favorites: Big Macs, Quarter Pounders, Chicken McNuggets.

Now, the chain has digital boards programmed to market that food more strategically, taking into account such factors as the time of day, the weather, the popularity of certain menu items and the length of the wait. On a hot afternoon, for example, the board might promote soda rather than coffee. At the conclusion of every transaction, screens now display a list of recommendations, nudging customers to order more.

At some drive-thrus, McDonald’s has tested technology that can recognize license-plate numbers, allowing the company to tailor a list of suggested purchases to a customer’s previous orders, as long as the person agrees to sign away the...