But while the two estimates may differ, they point to the same overall historical pattern: People are watching a lot more TV than they were decades ago. Liana Sayer, a sociologist at the University of Maryland who studies time use, cited two main theories as to why.

The first, she says, has to do with the thesis Robert Putnam put forward in his 2000 book, Bowling Alone—that Americans have, collectively, withdrawn from communal activities and civic life. The popularity of TV, Sayer told me, reflects “people’s desire to wind down and relax in a setting that they’ve got total control over.” Many people may feel that socializing with neighbors is taxing, while, Sayer notes, “TV is there, in your house, and it’s always available.”

Sayer attributes the second theory to sociologists such as Harriet Presser, one of the early researchers to note the rise of nonstandard working hours and inconsistent shift work. “She makes the argument that if individuals are working either very long hours or they’re working hours that aren’t in sync with other members of their family, or with their friends,” Sayer says, “their ability to engage in leisure activities that require the presence of somebody else, or require institutions to be open, is going to be far more constrained.”