In 2009, Laura Astolfi and fellow researchers at the University of Rome noted marked changes in cortical activity in the brain when subjects watched television. In a study, they measured the cortical activity with electroencephalograms and magnetoencephalograms while subjects watched television. They were interested in brain activity changes between programs and commercials and found an increase in activity during commercials. Their findings appear to bolster the theories of Edward Bernays, the author of "The Engineering of Consent," a treatise on how to use mass media to manipulate the public by using subtle appeals to irrational or subconscious areas of the human psyche.
Bernays used both print and audiovisual media in advertisements to powerful clients, though with print media he relied heavily on powerful images with simple, memorable words and phrases crafted for psychological resonance. With the introduction of television, even more powerful, moving images accompanied by resonant phrases could be delivered into living rooms during breaks between popular programs. A study conducted by Stanford's Elise Temple and published in "Proceedings of the National Academy of Sciences" in 2003 showed reading increased brain activity from activity at rest, while studies published in "Scientific American" showed generally decreased brain activity while subjects watched television, the variations in the Astolfi study notwithstanding.
Two factors that differ between television watching and reading are focus and engagement. Television transitions, which include cuts, pans and scene changes, disorient the watcher frequently from the kind of focus necessitated by reading, where recognition and interpretation of words and sentences force the reader to engage more intimately with the material. The frequent disorientation of television watchers is believed to force a degree of disengagement that results in passivity, which may be responsible for the reduced overall brain activity.
Studies have generally been conducted with isolated individuals, so there is little research, for example, on the focus and engagement of a group of people critically watching a film or a sporting event together. Reading also can be a collective endeavor. In situations where the television viewer and reader are alone, however, the evidence suggest that excessive television watching can dull brain activity and habituate people to passivity, while reading tends to increase brain activity even when subjects are not reading.