The riders I talked to average hourly wages in the midteens with tips, though I met a couple of Jedi Masters who cleared over $20. My rookie earnings added up to just under $10 an hour — $5 below the city’s minimum wage. (I’m donating them to The New York Times Neediest Cases Fund, which supports social-service nonprofits in the city.)

Postmates says its couriers in New York City average $18.50 an hour. But it counts only the time when a courier is out on an order as part of that hour. The long stretches I spent staring at my silent phone like a jilted boyfriend, waiting for it to ping? Not part of my workday, according to Postmates.

The apps roll out ever-changing and often confusing menus of bonuses and incentives borrowed from the video-game and slot-machine industries, engineered to convince riders that they may yet win as long as they keep playing. But with so many riders chasing the same prizes, they often fall short.

Also, the apps keep ratcheting down base pay so that even when a rider earns a bonus, “You’re basically paying the bonus out of your own pocket,” Professor van Doorn said.

In May, Postmates got rid of its guaranteed minimum of $4 per order. A company official said that the change was intended to discourage riders from rejecting longer trips, and that it had not affected workers’ earnings. But on a Facebook group for Postmates couriers in New York, the move was greeted with outrage. One courier wrote that she made $5.05 for doing two deliveries from 96th Street to 145th Street in Manhattan. “I’m done with PM,” she wrote.

Professor van Doorn interviewed dozens of riders and found that about three-quarters were riding for multiple apps, often simultaneously, to boost their earnings.