Excessive TV in Seniors Tied to Poorer Memory

A new study suggests that older people may want to restrict their TV watching in order to retain their memory and cognitive abilities. The study indicates that, among those 50 and older, watching three and a half hours of television daily directly relates to a decline in verbal memory.

Television and Cognition

There has been concern over the effect that television has on mental faculties since the medium was invented. However, most studies that examine the effect of television viewing on cognition focus on children. This study was unique in that it focused on seniors. It had long been theorized that there may be a link between excessive television watching and dementia in the elderly. This study lends some weight to that theory.

The English Longitudinal Study of Ageing followed 3,662 adults older than 50 years of age. The initial baseline testing had participants answer questions in 2008-2009 regarding their television viewing habits and other behaviors. There was a follow-up study six years later in 2014-2015. At each evaluation, subjects were also given tests on their verbal fluency and ability to remember language.

Impact of Television Viewing on Verbal Memory

An analysis of the study found that the study participants who viewed television for more than three and a half hours per day had a decrease in their verbal memory, averaging 8-10 percent over the course of the study. Those who averaged less TV watching only showed a 4-5 percent decline. Subjects were tested on their verbal memory by being shown lists of words to memorize and recall later. The decline was most striking among those with above-average cognitive abilities at the beginning of the study.

Interestingly, the study showed no link between television viewing time and declining semantic fluency. The semantic fluency test required participants to recall as many examples of a given category as they possibly could. Types of animals as a category, for example, would require the subject to then list as many animals as they could think of. Subjects performed as well on this regardless of how much time they spent watching television.

Passive vs Active Viewing Time

Researchers had long theorized that it was the sedentary nature of television viewing that was responsible for any cognitive decline, rather than the act of watching television itself. So in this study, special care was taken to eliminate sedentary activity as a variable. In order to eliminate this possibility, they compared television watching with other sedentary activities that involve interacting with a screen.

Television viewing is a completely passive activity, it requires little to no interaction from the viewer. The most input a viewer may have into the process is selecting the TV program to watch. Other sedentary activities, like playing online games or browsing the internet require active mental participation while remaining sedentary activities. Contrasted with television viewing, there is much more active interaction with the screen. This has been thought to enhance cognitive abilities like decision making and problem-solving.

Why Would Watching TV Decrease Verbal Memory?

The authors of the study found that there was a strong correlation between hours spent watching TV and cognitive decline, even when adjusting for sedentary activity. Why would this be? One possible explanation is the alert-passive state. In brain imaging studies, it was found that watching television resulted in brain activity that was more alert but less focused. Since it lacks the interactive elements of gaming or browsing, it seems the alert-passive nature of television viewing could be the reason for a decrease in verbal memory.

Another way the researchers theorized television impacts cognition is through the tense emotional states it creates. The experience of viewing drama, action, and violence vividly recreated on TV results in a state of heightened stress. This causes the brain to be bathed in stress hormones like cortisol which change the brain in profound ways. The prefrontal cortex, the part of the brain that controls learning and memory, has been shown to shrink under the effect of chronic stress. Stress-related changes to the brain may be partly responsible for any cognitive decline.

A third possible mechanism for the effect viewing television has on cognition is the displacement of other brain-stimulating activities. Time spent in front of the television is time that is not available for reading, playing cards or assembling puzzles. Those are activities that actually improve cognition. With less time for those stimulating pastimes, verbal memory weakens.

Television Has Some Benefits

The researchers have noted that there are potential benefits associated with watching television. Television dramas in particular have been shown to increase empathy and understanding. They are a window to the lives of others, whose background and life experiences may differ from that of the viewer’s.

Educational programming can deliver life long learning opportunities to those with limited access to the classroom. This requires that the programming is created effectively. Escape and distraction from life’s losses and difficulties is yet another advantage television provides. Indeed, people frequently cite TV viewing as a form of relaxation, but this needs to be weighed against the stress-inducing nature of certain types of programming.

More Areas for Study

Because this study was able to isolate television viewing itself as problematic for verbal memory, a new field of inquiry opens for researchers. The authors of this study ask if the nature of television content can be adapted for the cognitive needs of seniors, which may have applications for other age groups as well. More study on how the different types of TV programs impact cognition the elderly would be welcome. Since residents of care homes spend a great deal of time watching TV, perhaps the programs they watch could be tailored to be cognitively stimulating. They could also be provided with programming that is less violent, less stressful, and ultimately less damaging to memory. This would result in television that provides more of the benefits and fewer of the risks inherent in the medium.

This study focused on cognitive decline, which differs from dementia, but more studies on television as a risk factor for dementia, as well as its effect on patients with existing dementia, are necessary. There is evidence that as dementia advances, the desire to watch television decreases. This indicates that the reward of viewing television decrease somehow as cognition declines. This could also be a fruitful area for a type of programming tailored to those with specific cognitive needs, turning potential harm into a defined benefit.

Sources:

https://www.nature.com/articles/s41598-019-39354-4#Sec6
https://www.tuw.edu/health/how-stress-affects-the-brain/