This week Canadian researchers suggested that more screen time harmed toddlers’ development, in another skirmish in the long-running war over whether an iPad is a good child-pacifier. But where does the phrase “screen time” come from?

In the 20th century, film scholars opposed screen time (the running length of a movie) to “story time” (the duration of the events portrayed). Screen time was also the measure of total cinema showings in countries that imposed national quotas. It was first repurposed by Tom Engelhardt in 1991, in an article about children’s TV and video games (“Even a six-month-old spends an average hour and a half of screen time a day”). Now, iPhones come with an app named Screen Time designed to shame you into staring at them less often.

When you can do more or less anything via a screen, though, screen time looks like an unhelpful amalgamation. Is reading the essays of Arthur Schopenhauer on your phone really as bad as bullying people on Instagram? Perhaps we should be more concerned about “social media and noxious YouTube conspiracy video time”, although that is a bit of a mouthful. How about “cognitive garbage time”?