Readers above a certain age may well recall, several decades ago, regularly being told by parents and teachers that watching too much television rots the brain.
Now, research by two scientists at University College London in the UK suggests that, at least metaphorically, the oldies were right.
In a study covering a seven-year period, Daisy Fancourt and Andrew Steptoe tested the effect of television watching among people over 50 years old. Most research into the relationship between television and cognition, they point out, has focussed on children and adolescents – older people have been largely overlooked.
The researchers used data from a long-term project called the English Longitudinal Study of Ageing (ELSA), an ongoing population-based mission to collect information regarding health, wellbeing and economic outcomes for over-50s
To establish a baseline, they looked at television-watching data for 3662 adults recorded in 2008 and 2009. They then flipped forward six years and looked at levels of cognitive decline in the same cohort during the period 2014 and 2015.
They found that people who watched television for more than 3.5 hours each day experienced a decline in verbal memory – the ability to recall words and language patterns. The effect was most pronounced among those who had scored highly on verbal memory at baseline.
The finding was observational and thus cannot indicate whether telly-watching actually caused the language deficits, but Fancourt and Steptoe report that the association remained robust even after possible confounding factors such as mental and physical health, and socio-economic status, were taken into account.
Interestingly, the outcomes did not appear to be related to the amount of time spent sitting down. In many earlier studies looking at the effect of television on mental and physical health, the act of watching was assumed to be a proxy for sedentary behaviour. This research implies that being a couch potato and staring at the box operate independently.
Fancourt and Steptoe suggest the deleterious effect of long periods of time spent watching television may arise because of the nature of the medium.
“Television involves fast-paced changes in images, sounds and action and, unlike other screen-based activities such as internet use and gaming, television is the most passive way of receiving such stimuli,” they write.
The consequent state of “alert-passive interaction”, they conclude, might be the problem. They note that other screen-based activities, such as playing video games or searching the internet “can in fact have cognitive benefits”.
The research is published in the journal Scientific Reports. There is no truth to the rumour that it is set to be adapted into a television series.