Too much time spent on the internet could make some people reclusive and less likely to interact with people face to face, according to a recent report.
About one third of the 4113 adults in 2689 US households surveyed by the Stanford Institute for the Quantitative Study of Society (SIQSS), said they were online five or more hours per week.
And 13 per cent of those said they spend less time with family and friends, 26 per cent talked less to family and friends on the phone, and eight per cent attended fewer social events.
Professor Norman Nie, director of SIQSS said, "This is an early trend that, as a society, we really need to monitor carefully."
Some 60 per cent of regular web surfers said the internet has reduced their TV viewing, while one third said they spend less time reading newspapers.
"As of today, heavy internet users are still a small fraction of the total population," Nie said, "but that fraction is steadily growing."
Nie added that although most internet users send and receive email, "you can't share a coffee or a beer with somebody on email or give them a hug."
But he pointed out that the internet is an individual activity. "The internet could be the ultimate isolating technology that further reduces our participation in communities even more than television did before it."
One of the surprises, said Nie, was the degree to which people reported they work from home using the internet. Some 16 per cent of regular internet users said they work additional hours for their employers at home, since they gained internet access, without cutting back hours at the office. Only four per cent said they had cut back their hours at work since gaining internet access.
Nie said people need to do a more conscious job of examining the unintended and potentially negative consequences of constructing new electronic systems for information. "The human meaning of these changes remains unclear at present."
Electronics and computer chain the latest high street retailer to fall into difficulties
Incisive Media and Investec Asset Management supported fundraiser crosses Atlantic in 40 days
Alphabet's health sciences division Verily have been messing with AI algorithms
North Korea's cyber attack capabilities are expanding fast - and turning their fire on a wider range of targets