WASHINGTON (AFP) - Adult Americans spend an average of more than eight hours a day in front of screens -- televisions, computer monitors, cellphones or other devices, according to a new study.

The study also found that live television in the home continues to attract the greatest amount of viewing time with the average American spending slightly more than five hours a day in front of the tube.

The figure drops to 210 minutes a day of average TV viewing time among 18-24 year olds but rises to 420 minutes a day among those aged 65 and older.

The "Video Consumer Mapping" study was conducted by Ball State University's Center for Media Design (CMD) and Sequent Partners for the Nielsen-funded Council for Research Excellence (CRE).

For the year-long study, observers recorded the exposure of 350 subjects to four categories of screens: traditional television, computers, mobile devices and other screens such as store displays, movie screens and even GPS navigation units.

The study found the average amount of screen time for all age groups was "strikingly similar" at more than eight-and-a-half hours although the type of devices and duration used by the respective groups throughout the day varied.

It found that people aged 45 to 54 averaged the most daily screen time at just over nine-and-a-half hours.

The study did not include anyone under the age of 18.

Among other finds:

-- computer video consumption tends to be quite small with an average time of just over two minutes a day.

-- Adults spend an average of 6.5 minutes a day with videogame consoles with the number rising to 26 minutes a day among those aged 18-24

-- Adults spend an average 142 minutes a day in front of computer screens

-- Adults spend an average 20 minutes a day engaged with mobile devices with the highest usage -- 43 minutes a day -- among the 18-24 age group

"What differentiates this study from all other attempts to measure video exposure at the consumer level is its scale, the range of media covered and the fact that it is focused on consumers first and the media second," said Mike Bloxham, director of insight and research for Ball State's CMD.

"It's not a study about TV or the Web or any other medium -- it's about how, where, how often and for how long consumers are exposed to all media."