The average American now owns four digital devices and spends 60 hours a week consuming content across devices, a Nielsen survey released Monday found. A majority of U.S. households now own high-definition televisions, Internet-connected computers and smartphones, Nielsen said. On those smartphones, social media app usage is up significantly from last year, the survey found, with almost half, 47 percent, of U.S. smartphone owners visiting social networks every day. And a growing percentage of young people told Nielsen they refuse to part with their favorite networks -- even when nature is calling. Forty percent of young adults ages 18 to 24 use social media in the bathroom, which is up from 32 percent in the previous year, Nielsen's Digital Consumer Report found. More than half of adults ages 25 to 34 in the Unites States said they use social media while at work. Nielsen said it conducted its online survey with a representative sample of 2,020 adult social media users in the United States.