The traditional living room has been transformed into a digital media hub where the household watches television while multi-tasking via tablets and smartphones, Ofcom said.
Households are increasingly reverting to just one television, and 91 percent of adults tune in to the main set in the living room at least once a week, according to Ofcom's annual "State of the Nation" report.
A quarter of viewers regularly partake in "media meshing" - using devices to communicate about the programme they are watching.
Of those surveyed, 49 percent said they engage in "media stacking" to carry out completely unrelated activities such as social networking or online shopping.
More top news
Helicopters are searching for survivors who may be marooned after a weekend of heavy rain.
Thousands of people attended a protest on Copacabana Beach to demand presidential elections as pressure mounts on Brazil's leader to resign.
Brexit on Theresa May's terms could see the UK lose access to a database of information on terrorists and criminals, the Lib Dems have said.