Nice to see someone looking into this. The speed of stimuli processing isn't dependent upon novel stimuli, though. Stimuli processing is dependent on metabolic activity. Broda Barnes, in his book
Hypothyroidism: The Unsuspected Illness, describes how the perception of time deepens when the metabolic activity is normalized. Life is more exciting for young people not because they are young, but because people suffer from low metabolic activity later in life, and the world around is has been artifically limited, so life quickly becomes tiring and repetitive. People with healthy thyroids living inside a healthy social community are able to maintain the experience of novel stimuli during a lifetime, due to the experiences they chose. In depression and old age time goes by extremely quickly.
The big question regarding time is whether there are currently things happening in our realm - maybe electromagnetic in nature - which objectively shorten the subjective speed of time for all humans on earth.
Time probably goes by faster when the aether field weakens, because the field directly affects the energy system of the human body.
The problem is that it's hard to discern this form of time speeding up from the known effect of aging described in the Quartz article.