Older adults who watch more than three and a half hours of television a day experienced greater memory decline than those who watched less, according to an analysis published online in Scientific Reports.
To learn more about the effects of watching TV, a pair of researchers from the United Kingdom analyzed data from 3,662 participants in the English Longitudinal Study of Ageing, a long-term study of UK residents aged 50 and older (average age 67) that collects information on health and lifestyle habits.
Between 2008 and 2009, participants reported their viewing habits through a series of questions.
Based on those answers, the researchers split the participants into five groups: those who watched less than two-and-a-half hours of television a day; those who watched between two and a half and three and a half hours a day; those who watched between three and a half and four and a half hours; those who watched four and a half to seven hours a day; and those who watched more than seven hours.
Participants completed tests of verbal memory and fluency. In the verbal memory test, they were asked to recall 10 common words recited to them immediately and after a brief delay. For the fluency tests, participants had to list as many examples of a category, such as animals, as they could in less than a minute. Six years later, the participants reported their TV viewing habits and completed the cognitive tests again.
Those who watched TV for three and a half hours or more per day had an average decline of 8 to 10 percent in word- and language-related memory, compared with a 4 to 5 percent average decline for those who watched less than three and a half hours. No links were found between TV viewing time and differences in fluency.
Researchers also found that as television viewing went up, scores went down, a link that persisted even after researchers adjusted for income and sedentary behavior other than watching TV.
The authors suggested that watching TV may impact verbal memory through "cognitive stress,” which refers to programs with graphic, violent, or suspenseful content.
Another theory is that if people spend more time watching TV, they are less likely to engage in "cognitively beneficial activities," such as reading, playing board games, and cultural pursuits.
The researchers stressed their findings do not mean that TV viewing in older age is harmful. They point to evidence that adults who watch dramas compared to those who watch documentaries do better in tests, suggesting they may be better able to understand others.
Lastly, some studies have revealed that educational programs can be effective for learning when “designed appropriately.”
