The Real_Living report from the Internet Advertising Bureau UK (IAB) involved following the activities of nearly 1,050 people, measured by a mixture of surveys, passive filming, on-device tracking, daily diaries and biometric data.
This found that only 50% of UK online adults now regard the TV set as the focal point of their living room; 70% reported they ordinarily use a connected device whilst watching TV, a figure that rose to 87% of 16-34 year olds.
Around one third are checking emails (34%) or messages/texts (31%), while a quarter are shopping online.
And the biometric data revealed that about 60% of the time a person is most highly engaged during an evening TV session is in non-TV related activity, such as using a digital device or talking to someone.
Tim Elkington, chief strategy officer at the IAB, suggested that "all screens are now equal" and that entertainment formed only a small part of living room media activity.
"It's now a multifunctional space where people jump between individual and group activities, be it shopping, social media, emails, work or messaging," he said.
The study also debunked the notion that people cram non-TV related behaviour into the ad breaks.
The incidence of checking emails, for example, was found to be the same during TV programmes and ad breaks (both 34%), whilst texting/messaging was only 1% higher during the ad break than the programme.
In fact, the most common activity during an ad break was to go online via a connected device (35%), followed by talking to someone in the room (15%), leaving the room (13%) and changing the channel (8%).
"Connected devices and the realities of modern life mean behaviour in the living room is no longer determined by TV programmes and ad breaks," Elkington observed. "It is determined by the natural rhythm of device usage."
And one of the consequences of that is that advertisers will have to rethink how they can get attention in the living room, "because the opportunity to do so is far more limited, fragmented and competitive than ever before".
Data sourced from IAB UK; additional content by War staff