Why does time accelerate the faster we grow into adulthood?

Question

Accepted Answer

The Proportional Theory
The primary scientific explanation centers on the Proportional Theory. When a person is five years old, one year represents twenty percent of their entire existence, making it feel vast. By age fifty, one year is merely two percent of life, causing it to feel significantly faster.

The Role of Novelty
Our brains encode information based on novelty. During youth, the world is filled with new experiences and neural pathways, forcing the brain to capture more sensory data. As habits form in adulthood:
 Routine takes over: The brain stops recording repetitive events with high detail.
 Memory compression: When the brain recalls a span of time without distinct new memories, it perceives that interval as much shorter.

Neuropsychological Perception
Essentially, the perceived speed of time is a byproduct of information processing. Younger brains are busy learning; older brains are busy streamlining. By actively seeking out new hobbies, travel, and challenges, one can effectively 'stretch' the subjective experience of time throughout the entire human lifespan.