Why time appears to speed up with age

I wonder if the memory effect is related to emotional state - strong emotions result in stronger memory formation (I think I read this as a research finding as well). Strong emotions, in turn, are caused by new, challenging, and meaningful experiences. As we get older, our emotions tend to level out as we sort of "find ourselves" and settle into a routine. Break the routine, and memory formation snaps back to what it was in childhood.

Personally, I haven't noticed the same effect as you. I'm in my early 30s. I remember watching Perseids last Tuesday with a date much more vividly than watching them last Saturday with my friends. I remember my spring semester junior year of college (spent abroad in New Zealand) much more vividly than fall semester (spent in the same dorm that I lived for sophomore year). I remember 2009 (moved out to California, started working for Google) much more vividly than 2006 (lived at home and worked for the same company as in 2005). I remember Oct-Nov 2009 (spent on leave at home as my dad was dying in the hospital) much more vividly than Jul-Sept 2009 (settling in, nothing in particular happened).

Ditto. I've had this exact conversation with multiple groups of friends over the past several years. Interesting to see this form of the conversation's analytical deconstruction, though.

What about simple time lapse? With images and video the larger the time lapse the faster things appear to be moving especially with blur. What if something similar held for memory?

The key memories that are remembered will typically have longer lapses for the older than for the younger. Cognitive expectations might then correct this gap by fudging a perception or sense of elapsed time, creating a quickened time lapse like effect for experiences, which strengthens as you get older.

It would be interesting to ask people with autobiographical memories how they perceive time - according to my analogy it wouldn't change since they maintain most 'frames'.

From an experience:

Difficult time passes more difficultly, i.e feels longer. Example on a day if you are fasting, time always seems earlier than what you expect. For example on days I may think 'Gosh its still 12 PM, still 7 hours to go before the fast breaking time!'

Only yesterday, the fast breaking time was 6:54 PM. And my wife called at me from down stairs to come down for it at 6:53 or so (I work from my SOHO on the upper level), I thought gosh 1 more minute, how can I wait!

So it could mean that the perceived time (that has passed) is also a function of how frequently we sample it. Or if differently said, how much we 'live in the moment'.

Edit: minor rephrase for clarity.

This reminds of of a similar calculation I did in college when thinking about big computing problems.. I called it "hurry up and wait".

Assuming Moore's law continues (computing power/$ doubles every 18 months), and you have a big computation to do, should you start now or should you wait?

If you have $1000 to spend on a computer and a problem that's going to take 3 years for it to compute, you can actually wait 1.5 years before you start. The computer you buy then will be twice as fast, and you'll finish at the same time.

On any problem that takes more than 1.5 years, the fastest thing to do is just wait until you can afford a computer that can complete it in 1.5 years.