Their not alone in their thoughts. Dr Soma Sengupta, a neurologist at Tufts Medical Centre, suggested that unlike reading, learning a new skill, or working, watching TV “often requires little active mental engagement”.
Article source: https://www.huffingtonpost.co.uk/entry/watching-tv-very-often-dementia-risk_uk_6a6b2ba0e4b0fddbd71333c4