There is no good answer just yet, but it is either an information theory phenomenon (brain as a prediction machine theory), or this could be linked to activity

There is no good answer just yet, but it is either an information theory phenomenon (brain as a prediction machine theory), or this could be linked to activity of dopaminergic, cholinergic systems, or even changes to base neuron firing rates. There is a myriad of possible root causes. Personally I think the dopaminergic hypothesis is not entirely incorrect [1], and there are treatments for this aspect of ageing. 1. https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2022.927160/full https://www.frontiersin.org/journals/neurology/articles/10.3...