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Why time appears to speed up with age (everything2.com)
250 points by rlander on Aug 19, 2012 | hide | past | web | favorite | 100 comments

  This makes sense; for instance when you are 10 years of age, a year 
  represents 10% of your life, and seems like a very long time. However, 
  when you are 50 years old, one year has reduced to only 2% of your 
  life, and hence seems only one-fifth as long.
Interesting hypothesis, and he makes it look very scientific with the formulae and all, but it's still a wild crazy guess that delivers no actual falsifiable prediction. I think for claims of such magnitude, there should be a modicum of neurological or information-theoretical basis involved - instead we get to read repeated statements about how groundbreaking the idea is.

The article makes claims that at 30 life is essentially 3/4ths over which to me, while holding no subjective truth as far as I can tell, at least exhibit some self reference in the way that after three lines of statements the article's content seemed 75% over yet the actual text went on for much longer.

Subjectively time seems to go by faster the older we get, but that doesn't mean these bold claims are necessarily anywhere close to the truth. Personally, my relationship with time has certainly changed over the years, including the perception of a speed-up, but I also notice that some activities or states seem to last just as long (if not longer) subjectively as they did when I was 16.

My pet hypothesis is there are multiple factors involved in "the speedup", and that a large factor of it would actually be that our brains don't store repetitive events very well. This would mean as we get more experienced, an increasingly bigger amount of the average day consists of things we already did many times before so we don't store those moments in memory. That would result in increasingly large memory holes over time, which our brains then glance over as they piece together our past - thus resulting in an apparent speed up. This would also explain why days with unusual content seem to last much much longer than others (at least that's my experience).

"A large factor of it would actually be that our brains don't store repetitive events very well."

My theory, which is logically consistent with yours, is that as we get older we spend more of our cognitive cycles thinking in terms of abstractions rather than using our senses to process direct experience. This is partly because as we get older we tend to immediately place things we experience into categories and then move onto processing these abstractions rather than continuously observing reality directly and unfiltered. So the other part of the theory would be that when we think in terms of abstractions, time goes by much faster than when we focus on direct sensory experience. It's likely that novelty also plays a role here as a mediating variable, in that we tend to pay more sustained attention to novel phenomena rather than immediately placing them into conceptual buckets and moving onto the next thing.

I also like this theory because it's consistent with how drugs that alter our sensory perceptions and make us focus more on our perceptions also tend to subjectively slow down time. Anyway I have no idea whether this is correct, but IMHO it's a much better theory than the original, which isn't especially logical and doesn't even really make sense.

> we get older we spend more of our cognitive cycles thinking in terms of abstractions rather than using our senses to process direct experience.

This would explain why vacation makes time slow down, yet go fast at the same time. The slow down for the new experiences, environment. The fast - for the lookahead-cache driven feeling of sometimes anxiety/dread of going back to the daily routine.

I've often thought the same thing. It has me thinking cautiously about the sociological implication rapidly expending 'senior' demographic, growing life expectancy, and the rapid pace of world changing technologies. Is there a point where senior citizens can't keep up cognitively, despite the medical advances that may keep their bodies younger? And further, is there a point where their dominance as a percentage of society means we need to slow our adoption rate of consumer technologies to account for neurological barrier?

I also think about the people who want their brains crygenetically frozen after they die. Assuming they die old, with this cognitive scaffolding adapted to life today, I can only imagine the impact of 'waking up' into a world 100-300 years in the future, with such a drastically different world. That sounds psychologically crippling to me.

And finally, are there techniques I can take advantage of now, when I'm [comparatively] young, to keep my brain receptitve to new ideas, mental models, and raw sensory input? Meditation? Arts? Travel? Literature? All of the above, and if so, where do I find time for it all, while advancing my career?

> All of the above, and if so, where do I find time for it all, while advancing my career?

As the cliche goes, if you don't find time for it now, you'll pay for it later.

Walking with bare feet and/or walking on uneven ground +1


Art +1

"For Healthy Aging, a Late Act in the Footlights"


You just described my theory exactly. Humans have to learn how to exist in the "zone" of mental abstraction... this is necessary for advanced cognition, but while we're doing it we don't really notice the passage of time.

I can't help but wonder if the hours I spent waiting for the last few minutes of boring class periods to end during my schooling might have actually been great training for "zoning" where the sped up passage of time is actually the goal.

> as we get older we tend to immediately place things we experience into categories and then move onto processing these abstractions rather than continuously observing reality directly and unfiltered.

Wow, this makes so much sense, and accounts for why (in general) people get less receptive to new ideas as they get older: no categories to place the abstractions in.

While we're on pet hypotheses, what about the fact that the brain simply gets bigger? If neural signals–maxing out at ~100 m/s–took longer to traverse the average distance through the brain, one's perception of time would seem to slow down.

Anecdotally, when I was 8 or so I once sat there for an hour or so memorizing the rate of the clock (so I could later mentally estimate intervals of time without a stopwatch). At the age of 23, I noticed and then calculated that a second in my "internal" clock was about 1.3 seconds. Since then I have used VLC to re-watch movies I saw as a child at ~80% speed. The musical rhythms seemed closer to what I remember.

Obviously this is insufficient support by itself, but I's love to see this phenomenon studied more rigorously.

I think there might be some experimental data in support of the fact that (at least some types of) neurons get slower as we age, though I believe it was for metabolical reasons not due to connection length. I still think you might have a good point there not only due to that cellular slow-down, but also because I would certainly expect an increase in connection density, thus leading to longer computations.

I seem to recall an article from Joel on Software about the same phenomenon from a procedural point of view, where he compares increasingly complex institutional reaction times to the increasing amount of ritual that is being performed before we leave the house (with old people taking the longest time, because based on past experience of all things that went wrong in the past, their checklists before leaving the house become absurdly long over time).

Just an interesting side observation about the VLC speed thing: my personal sense of rhythm has always been so bad that I couldn't tell the difference between 100% speed then and 80% speed now. But an observation I recently made was that I can now comfortably listen to videos at 110% or even 120% their speed without losing content - something I certainly couldn't do at a younger age (in fact, I remember I often had to pause recordings in order to think about stuff that just happened or even just to empty my "language recognition buffer" before I could move on). So while it may well be true that 1 second doesn't last as long for me as it used to, I certainly seem to have become more efficient at processing some types of data.

Wow! This sounds like you could design an experiment for this. It might take at least something like 5 years to see any results. But thats a timeframe many scientists should be willing to pursue.

If you don't want to do those experiments yourself maybe you should eMail some Professors who are interested in this topic.

I think this comment is a slight bit too critical for an OP that's obviously in the genre of playing with ideas. (Most of everything2 seems in this genre.)

> a large factor of it would actually be that our brains don't store repetitive events very well

Depends on what you mean by "very well". Aggressive data compression is usually considered a good way of storing things.

My criticism of the article is so harsh exactly because it does not represent itself as merely an idea, it instead attempts to convey the impression of being a groundbreaking scientific discovery.

> Depends on what you mean by "very well". Aggressive data compression is usually considered a good way of storing things.

We're fundamentally in agreement on this. It is, however, not lossless compression, and that's in part where I would assume the speedup comes from.

> My criticism of the article is so harsh exactly because it does not represent itself as merely an idea....

It's literally titled "Why time appears to speed up with age (idea)".

>>This would also explain why days with unusual content seem to last much much longer than others (at least that's my experience).

I've heard this explained in part because of how our neocortex works. New events tend to require the involvement of more layers of the neocortex than ones that are redundant and routine. This is part of the explanation for the time dilation we experience when surprised by something like a car crash or a thrill seeking adventure. Your mind is fully engaged much the way it was when you were younger and everything was a new experience. As your mind adapts the neocortex handles the events more efficiently; more reflexively. Your mind subconsciously ignores the sensory inputs that don't surprise you.

For this reason, it's often advised that if you want to slow down the apparent passage of time just change your routine. Granted...your neocortex would probably even adapt to this.

Cortical layers tend to be more of a way of dividing a specific low-level task up into sub-functions of information processing. For example, they do different networking/interconnect jobs in different layers and as one would expect different areas of the neocortex have varying layer counts (ranging from 1 to 6).

A more comprehensive computational unit of the cortex is actually the neocortical column which is a "horizontal" patch of neocortex. This is a functional unit that is probably very close to a microprocessor in analogy in that it contains a set of variables, some processing rules, input and output wires, and the capability of executing functions. A whole patch of cortical columns forms a sort of processing center, and interestingly enough, those tend to be specialized for certain kinds of information processing tasks. That's why in an fMRI scan whole areas of the cortex tend to light up together, and it's often the same areas geographically even if you scan a lot of people.

So if we're talking about a theory of localized neocortical involvement, my first impulse would be to check out those specialized areas for (non-)activity - something that led to pretty good empirical results before in related studies - as opposed to using the layers for that hypothesis.

Yes, that's a closer description than what I recall. My understanding is based on a book I read several years ago: http://www.amazon.com/On-Intelligence-Jeff-Hawkins/dp/080507...

I'm also partial to the "perceived time == amount of new experiences" theory. Some years seem much longer than the years that came before them because i had lots of new experiences those years.

Your pet hypothesis and mine are quite similar. Hey there pet hypothesis buddy.

Once you get a good routine down, you figure out the best grocery stores for everything, find the best routes to and from work/school, punch a clock for half your weekday waking hours, days start blending together. The time spent doing things like washing dishes, doing laundry, prepping meals, shopping for consumables, your brain is on autopilot for most of that time once you have done those things 100+ times.

Variety being the spice of life and all, doing new things forces you to actually engage your surroundings and have memorable experiences.

As someone who's in his fifties, I can say that while this is an entertaining concept, it doesn't really map correctly. At least not for me.

The passing of time has always seemed to me to be more of a function of memory.

When I was younger, my memory was _much_ better. And much more vivid. It was in HD. I noticed by the time I was in high school that not only was my memory worse, but that it was of much lower quality. Interestingly enough, though, I noticed that early memories, while less vivid than I remembered them, were often still more vivid than more recent memories. By the time I was in my 30s, things were much worse. My doctor assured me that this was normal, and by the way, expect it to get worse still.

My father, who is now 96, can remember things vividly from 80 years ago and more, but can't remember what town he is living in at the moment. He can remember chemistry and physics he learned long ago, but now he has trouble working the new flat panel TV we bought him. (This is only partly the fault of age, the UI experience on the TV is worse than abominable. Steve Jobs would puke.) This is interesting, because he _built_ the first radio that he ever owned, back in the 1920s.

The most heart breaking thing recently, is that my mother passed away a few months ago. She'd been with him constantly for the last 65 years or so. And he keeps looking around for her, and then after a moment remembers she's gone. He often doesn't remember the event, but it is still fresh as a state of being, even after several months.

So for my father time's passage seems instantaneous and never changing.

Duration is yet another issue.

Current time, you know, right now, passes for me at more or less the same rate. It's much more effected by things like boredom and engagement than anything else. If I'm waiting on something, things can take forever. If I'm doing something, it can go by in a flash.

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).

"I wonder if the memory effect is related to emotional state - strong emotions result in stronger memory formation"

Emotion is definitely highly linked to memory. E.g. you may be familiar with state-dependent memory:


This is where certain memories are best recalled (or can only be recalled) when one is in the same emotional state as when the memories were created. And I don't think there's any question that events that occur when emotions are stored the most strongly; that's basically half of what emotions are for.

It's difficult to say exactly how the density of memory is linked with perception of time. I would posit though that experiencing a variety of strong emotions on a regular basis is important for maintaining both good mental health and a well-functioning brain.

In your first point, you're thinking of what Psychologists refer to as "Flashbulb Memories" [1]. In general, research has found that people despite being very vivid memories with a very strong confidence from the memory-owner, there is no evidence that they are more accurate than any other memory.

However, with regards to the discussion, it is clear that the perception of stronger memory formation is definitely linked to emotion or emotional arousal. And really an individual's perception is an adequate flag for me. I might reframe the passing of time being tied to a root cause of emotion/emotional arousal.

[1] http://en.wikipedia.org/wiki/Flashbulb_memories

I believe the reason is whenever you remember something specific, the neurological pathway to that piece of information gets stronger. For example I was taught parts of the Quran between the ages of 8-14. I still know the verses because I use them daily (22-16 years later). The pathways are strong.

It may also simply be that your brain learned to simply retain what seems important at one stage and disregard everything that looks alike. Example: in your eighties you can easily remember the time you had your first kiss if you only kissed 3 guys/gals in your lifetime, but if you kissed every last person at the party every Saturday night, then you probably will forget.

Yes, I agree - it's related to memory. NPR had a good podcast on it a couple of years ago:



Time seems to go slower when we have tons of things to remember, when we are adding many memories in short periods.

Probably not the article I needed to see after coming home from moving my oldest into his dorm. Guess I might as well go get a rocking chair on the lawn.

Actually, I think this article is wrong in one important way. It doesn't take into account the effect of laying down new memories. The more, new experiences you have, the slower time appears to have passed [past tense, how it's remembered], while, paradoxically, making it pass [present tense, while experiencing] go faster.

So, spend all your time on the couch, watch time pass slow but evaporate. Go do something new and different, watch it fly by while having had more there.

Memories play weirdly with verb tenses...

Good observation on the memories.

During intense periods of memory-forming activity, you feel like time passes quickly, because more things are packed into less time and you move on from one thing to the next (think camps in your childhood when everything was exciting, there was a competition to prepare for, etc.). Once it's actually over, you felt like it just zoomed by so quick, but was packed full of stuff.

It's the same with the grade/primary-school years: each year feels so full of experiences, but before you know it you're in primary/grade 6 and at the start of a new phase, wondering how you got there so quickly. I used to be almost scared by how quickly I moved through the school years, thinking I'd be an adult in no time.

I think young people just tend to have much more packed into their time, which makes it feel longer. You literally live more when you have more different experiences in the same time. That's why I regret it when I think back and realise I haven't been doing anything much different over the past week. I'm going to have to schedule better and make some time for salsa/whatever classes.

So yes, I strongly agree with your conclusion:

> Go do something new and different, watch it fly by while having had more there.

Wring life out of every day.

I also agree. When we get older, we establish a routine: get up, go to work, do errands, etc. When we're young, yes, we might have some routines but we're constantly meeting new people, learning new things, and facing fresh, new situations. For me, ever since I graduated, the past 6 years have been one HUGE blur...

Try On the Experience of Time by Robert Ornstein. Has some fascinating experimental results.

Your comment reminded me of this wonderful video: Moments


For me, this was well worth watching. I bet the age of the viewer (amongst many other things of course) has a large affect on the individual impact.

I had come across this concept about a year and a half ago. Read some article about how our brain works to store new experiences and therefore time slows down. That's around the time that I left my full time job to travel full time! I even wrote an article on our travel blog about it:


This guy has definitely done a very quantitative analysis of my qualitative hunch. Subjecting myself to new experiences, new places and new environments everyday has definitely made time slow down.

My last birthday actually feels like it was a LOOONG while ago. That's because I threw in a bunch of interesting and new experiences over the last year.

I think the real way to feel like your 'real age' is to subject yourselves to new experiences as much as possible. Take a new route home, go to restaurants or parts of your city that you've never been to, learn a foreign language or salsa, learn a new sport, or if possible, travel! :)

> This guy has definitely done a very quantitative analysis of my qualitative hunch. Subjecting myself to new experiences, new places and new environments everyday has definitely made time slow down.

That's interesting, because most people would say that time seems to go faster when subjected to intense learning/experiences.

For example, from another article on HN's front page right now: http://techcrunch.com/2012/08/18/how-instacart-hacked-yc/

> The next day, I arrived at the meeting location. I faced four YC partners and a barrage of questions about how my business worked and why it would succeed. We talked for almost an hour, but it felt like just a few minutes. I answered questions non-stop.

Perhaps when looking back, time seems to have stretched out during those learning-intensive experiences? But at the moment of the experience, time sped by?

I suppose it depends on the experience. Time does fly by when you're having fun but I suppose it has to do with the richness of experience as well.

If you're subjecting all your senses to new experiences (say.. eating a new dish in a strange place - sensory overload for smell, taste, sight and sound), maybe your perception of time is slower.

It's hard to put a number on how we perceive real time I guess, but boring tasks do tend to stretch out into infinity.

I think the article is however discussing the way you remember time. It all has to do with our brain processing and storing memories. That ability can only be jogged by having new ones I suppose.

These topics could make for an interesting study, not much is yet understood about our perception of time.

Interesting, this reminds me of a quote from Josh Foer's book about memory: "Monotony collapses time; novelty unfolds it. You can exercise daily and eat healthily and live a long life, while experiencing a short one. If you spend your life sitting in a cubicle and passing papers, one day is bound to blend unmemorably into the next-and disappear. That's why it's important to change routines regularly, and take vacations to exotic locales, and have as many new experiences as possible that can serve to anchor our memories. Creating new memories stretches out psychological time, and lengthens our perception of our lives."

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.

Is anyone here but me old enough to know what J. Irr. Res. is? [1]

This comment thread makes me wonder.

According to the chart in the article, I have precious little time left. Please try not to suck all the joy out of my remaining few minutes.


[1] Or maybe I'm the last one on Earth who still reads the footnotes?

[2] This is the famous recursive footnote. [2] Please enjoy your trip through the stack.

[3] This tail-recursive footnote should really be optimized into a loop. [3]

You needn't be old to know what J. Irr. Res. is; you only need to be paying attention.

Journal of Irresponsible Research?

My theory is different. Our brains work like film cameras, the faster the camera is rolling the slower time in the film seems to be going during playback. Because less time has passed since the last frame was captured. The slower the camera is rolling the faster the film seems to get when you play it back. Our perception of time is based on comparing what we last remember while we were conscious with where we are in time currently. This is why daydreaming while driving makes your trip seem a lot shorter.

I call this "Brain Idling". When we're young our brains have a lot of grey matter and we're addicted to information accumulation, talking, chatting, and being mentally stimulated. As we age we stop learning (no school, no collage, nothing new going on in life), have less grey matter and start going on auto-pilot. When we drive to the store, when we shop for groceries, at work, at home. We've memorized our lives so well we no longer think about what we do, we just naturally do it on auto-pilot and our minds start to "idle" a lot more that usual. The film in our camera-like brains is snapping images at a much slower pace. A lot of time is passing between mental snap-shots. So when we look back (playback) the events of the day (all the things we remembered) it feels like time has flown by at light speed.

I freaked out over how fast time has flown by after I hit 21 and tried out an experiment. I installed "talking clock" for windows on my pc and made it announce the time every 5 minutes. Yes. For the whole day. Every day. After the 2nd day of using this technique time slowed down by massive amounts. A day felt like a week. A week felt like a month. It was insane. I felt like I was young again and the world was moving at a glacial pace. There are downsides of course, it's unsustainable. You have to take breaks every other day or so otherwise you get used to hearing the time and ignore it. It can also get exhausting when your brain can't take a break and daydream or idle and think about nothing. But it does work. I wanted to write a nice big article on it but I'm so swamped by work on projects and new clients needing UI/UX consulting that I just keep putting it off. On the plus side I've discovered a way to slow down time (at least for me).

"When we drive to the store, when we shop for groceries, at work, at home. We've memorized our lives so well we no longer think about what we do, we just naturally do it on auto-pilot and our minds start to "idle" a lot more that usual."

I like this because it reinforces my belief that time moves subjectively slower in the immediate period following significant environmental changes. The first few days of a vacation, for example, pass very slowly in my mind but the longer you remain on vacation the faster the days go by. Same goes for the first few days of college classes, or the days following a relocation to a new area.

I disagree with the original article because the rate of the passage of time seems to correspond more with the amount of new stimuli we experience, which (in most cases) just so happens to become less with age.

The 'film camera' metaphor is how I have always imagined it works as well. It makes sense from an evolutionary standpoint. It's critical that you are able to retain knowledge in your 'formative' years. But after a certain point it less important to record new information. I have always wondered if the amount of info we store drops off proportionally or exponentially.

Consequently, when someone has a bunch of adrenaline dumped into their body, they often say that time 'slowed down.' I believe this is further evidence that our brain boosts the bit rate on our memories at critical moments.

Neat idea. OS X's clock can be configured via System Preferences to announce the time on the hour, half-hour, or quarter hour, but not every 5 minutes. For that, save the program below in $HOME/bin/saytime:

    use POSIX;    
    system "say", "It is now " . POSIX::strftime("%I:%M %p", localtime);
Then add the following line to your crontab:

    */5 * *  * * $HOME/bin/saytime

I'm trying this... Here's the C# code to SpeechSynthesis the time every 5min http://pastebin.com/MxTh3zHH Add reference System.Speech

Could you please email me? I was unable to find contact info on your web site. Thanks! :)

Well that's no good. I'm a ux/ui person. I must have failed. It's the mail icon (next to the twitter, skype, and kickstarter icons) in the sidebar on my website.


This is interesting, I hope you write the article some day, I hope you can find the time.

Subjectively a good way is to remember how long summers felt when you were a kid. A summer felt like forever in the first couple of grades. Now think how long summers feel now, they just sort of fly by. It is kind of scary.

Remember my grandma sometimes got confused what day or week it was and as a kid I could never understand that. How can you miss such a long period of time like a week and not notice, but now I start to sort of understand.

I wonder this exact thing. Sometimes I wonder if the lack of boredom plays a role. As a kid you feel bored a lot more.

To be fair summer vacation is shorter in most areas than it used to be due to an extended school year. The standard used to be 180 instructional days for kids, per year but it keeps creeping up there every year teachers renegotiate their contract for a raise.

It is more than that. Summer felt as long as a year feels now, it is not just a couple of days of difference.

Note that this is a joke paper written for the Journal of Irreproducible Results: http://www.jir.com/

I can't find any evidence for this on either site.

You did not look very well.

The article by T.L. Freeman exists. It is in: http://www.amazon.com/The-Best-Journal-Irreproducible-Result...

You're not looking very well either. The author / pen-name / anything sounding anything like the article isn't in any of the information on the Amazon page, nor is it anywhere in JIR's list of 'selected pseudonyms'. Google searches of www.jir.com find nothing, nor does going through a large portion of the site that I could find.

To be clear, I admit it's possible, maybe even likely. But nobody has shown any evidence that it's true, just a claim and a link to a page that does nothing to support it.

It is not on the internet, so it doesn't exist?

I happen to have that bundle somewhere in my basement but won't bother to dig it up. I remember that joke-publication quite well.

Even if it's not to be found on the web, it's at least referenced by others. That's an easy find.


Note that that one was published in '91, so before the article by Professor Pi.

Not at all. But if it's not on either site pointed to as evidence, it's not evidence. It's like saying "unicorns exist, see here: http://en.wikipedia.org/wiki/Wombat ". Or "unicorns exist, I have a photo in my basement". Why would I expect anyone to take that as proof?

No, you pose this as an argumentum ex silentio instead of a simply asking for a link to the reference or even a copy of the article. So why should I be bothered to dig this thing out of my library?

Well, at least I gave you a reference to the article. Finding that reference should have taken you no more than two minutes.

The answer to "Why time appears to speed up with age" is to be found in the messy details of neurology, genetics and evolution, not in an aesthetically pleasing mathematical formula.

I'll just pick this one: it's almost as if this article was partly whimsical, and the idea was to inspire, not prove anything. And the aesthetics of both the formula and the argument are actually the point here. It's a kind of entertainment, not really science, and that's how it's supposed to be.

Also, this is Everything2, the article is from 2001, when there still was 3 people who knew what Everything2 is.

Groundbreaking? Maybe in that someone actually worked out the math for it (which seems trivial enough) and submitted it somewhere. A very large number of people I've chatted with from 10 years old an on have come up with this same theory, relatively independently, they just never worked out the full numbers because they realize that it's a gross oversimplification.

More specifically, this seems to ignore a small thing called 'nostalgia'. How long were the blissful summers of our youth without this rose tint?

Yeah, I remember hearing the "Time moves faster when you're older because it's a smaller fraction of your lifetime" theory from my 3rd grade teacher, and then in college I made the "And then if you integrate that rate over time, you get a logarithmic progression, which matches with experimentally observed fetal & childhood development, and OH MY GOD I'M BRILLIANT!" connection. Then my friends thought I was weird.

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.

Time seems to speed up as we get older because life gets less memorable and less surprising. When you're growing up, life is filled with novel and surprising experiences that are used to anchor our memory because of those aforementioned qualities. Psychological time is directly related to the formation of new memories. As we grow up, everything gets into a routine that we barely notice at all. Just think of how much you remember of your daily 9 to 5 for example.

This phenomenon has been studied several times. In 1890, William James wrote the following in his 'Principle of Psychology': "In youth, we may have an absolutely new experience, subjective or objective, every hour of the day. Apprehension is vivid, retentiveness strong, and our recollections of that time, like those of a time spent in rapid and interesting travel, are of something intricate, multitudinous and long-drawn out…But each passage year converts some of this experience into automatic routine which we hardly note at all, the days and the weeks smooth themselves out in recollection to contentless units, and the years grow hollow and collapse."

My father always says life is like a roll of toilet paper. The further you get on the roll the faster it spins and the less of it you have left the more you cherish it.

Time is clearly a solid and measurable component of our physical world but our perception of it is warped by our own personal experience.

My wife can sit next to me for 8 hours and futz around the house etc while I sit with my headphones on and code 'in the zone'. I come out of the zone feeling as if I had just experienced only maybe an hour of zone time and she will laugh and point out the window at the dark night. :-)

I have six children, a daughter-in-law, a grandson and two cats. My life is clearly not moving any faster then my children but I do keep reminding them that as they get older they keep making me older!

I would argue that actually life goes slower the older you get. You have more context against the rest of your life and the OP might be using that as the reason we perceive life going quicker. But to me it's more like the "weight" of my life to date allows me a lot more perspective, I often measure an event against the birth of a child, a marriage, a house I used to live in etc. Less about the MM/DD/YYYY and more about the "Around this event this happened".

When time seems to have moved quickly is when you're talking to your mom and dad about your grandson and the day your baby girl was born and how they're going through all the same things you did when you were having children. It's the reference points that stun you. That somehow 25 years just vanished in a flash of light. But the reality is this is the same as this group talking about TRS-80 Model I's with 4k of memory. A lot has happened since then even though it was sort of like yesterday for those of us who lived through 300 baud modems and 16k memory upgrades.

I would argue that the effective age of people vary with their behaviors and environment.

For example, I've seen 60 year old in australian outback on horses doing heavy work, as if they're 40. And I've seen 60 year olds in australian capitals barely doing anything of their day.

Which do you think will go extinct first?

I'm going to argue that simply "we are what we repeatedly do". Some people act old at 50, some people act young at 70.

For example, my uncle in Europe has acres of property, works in it every day, goes dancing with the local "brotherhood" and would drink you under the table any day of the week. And he's close to 75.

Trying to explain people with mathematics is similar to trying to explain women with science. It may work, barely. (no pun intended, just a cheeky joke)

The key to slowing down life is variety. As a child every year was distinctly different: even today I can remember each school year because I had a different teacher, a different homeroom, etc. As an adult each of my jobs has been on average 4-6 years. Each job is a bit of a blur; the years at the same job are difficult to distinguish from each other. To slow down time, make sure you do different things each year: trips, projects, roles at work, etc. The more your mind can distinguish the years, the slower time seems to move. Try it - it works!

I've always held the opinion that time is the number of events, realizations, ideas, and new experiences.

When you're kid, everything is new from what happens on the sandbox to school to friends to foods to afternoons alone to crossing over your old boundaries in general, in both physical and emotional sense. So much happens in a month that it equals five years for an adult.

When you're an adult, much of everything is something you know. The fraction of new things in your life depends on your own activity. Even if you wanted to be on the bleeding edge of life, you generally still have a job and a lot of routines in life—routines that might not be set by you but will still affect you. And routines and repetition doesn't count.

The key to adult time is to realize that the mundane things aren't the same, ever, even though they seem like it. You never know what will happen: there is newness every day, in everything you do, if only you can unlearn to dismiss it.

The other path—the path that isn't sustainable—is to start reaching for experiences intentionally: after you've climbed all the mountains and dived to the deepest caverns of the waters, done the craziest roller coasters and raced the fastest races, you're still not much more ahead of where you started. Those things can be done for fun but what I'm referring to is the trend of experience-hunting which is a reaction to the pace of finding new things in life that has slowed down since childhood.

This article and concept reminds me of thhe beautiful "game" by Jason Rohrer, "Passage"


The fluff in Freeman's article (Journal of Irreproducible Results, I think) is the same cheerful fluff students were subjected to in the non-honors physics class at my high school in the 1980s, where the point of using physics predictively went out the window (leaving only untestable descriptive math, which isn't a waste of time, but could be applied to something testable), and with the same fundamental failure of simply not caring whether there might be an underlying mechanism related to the impression of remembered time versus the subjective speed of time currently.

A change in behavior can also have a huge impact on how fast current time is flowing. A simple hypothesis that the subjective rate of time passing is related to the intervals between encounters with the unfamiliar easily leads to a more fruitful set of thought experiments than Freeman's weak exercise. And potentially one that could be rephrased in biological terms.

I've noticed that when I take trips to elsewhere in the world, the more different the place, the more time dilates, both while I'm there and in memory afterwards. Doing only the familiar is the recipe to time slipping by, unmarked and unnoticed, like driving to work and realizing upon arrival that one has no memory of the trip.

So the question is: What should you do to extend your subjective time?

The premise is completely wrong. If you are young, you don't know what percentage of your life one year is.

More likely explanation is the compression of memories: if you experience things that are similar to things you have experienced before, they won't use up as much memory. Think about your daily commute to work: can you remember every single day you commuted? Or did all the commutes blur into one?

The brain changes with age and perceives the passage of time differently. Just like your face changes with age and perceives touch differently.

The pop science is here:



Not as lazy as the article's speculation. There is an experiment!

The experiment is people of various ages are asked to estimate a minute with their mind. Older people overestimate, children underestimate.

Your brain has a clock, a set of neurons that fire at a relatively consistent interval and help synchronize the rest of the brain. As you age this brain clock's interval gets longer.

Forming fewer new memories because of lifestyle changes is speculation. Without widespread changes in the brain making new memories more difficult to form, you'd still form a lot of new memories, even with your boring adult lifestyle.

What is this SEO spam garbage? Every single link including the reference goes to junk pages and the article itself is cut & pasted all over the internet.


everything2 is most definitely not SEO garbage. I'm pretty sure it predates the concept of SEO. It has a very genuine community, and its content is pretty close to 100% voluntarily user-generated.

It's kind of like a proto-wikipedia, without the requirement for maintaining a neutral point of view, supplemented by freeform creative content. Maybe more like the collective journal of a certain type of young geek from the first half of the last decade. Lots of essays and painfully earnest poetry. It was initially associated with Slashdot.

As for the content being spammed all over the internet, I would guess that E2 is a reliable and extensive source of high-quality, human-generated text, with a dense network of contextually valid links included. Why not just scrape wikipedia? I'm not sure.



Brian Skinner, physicist and basketball analytics extraordinaire, wrote a really nice blog post about this 3.5 years ago [1]. Mining the comments from that post shows it's been banged around numerous times before that [2][3].

[1] https://gravityandlevity.wordpress.com/2009/04/02/parenting-...

[2] http://www.nytimes.com/2009/04/21/science/21qna.html?_r=1

[3] http://web.archive.org/web/20071116094344/http://ourworld.co...

Here is my take. When you experience something new, your brain works overtime to learn new things. Thats why in a familiar setting time flies by. I guess thats why some people are adventure seeker and travelers. At old age most of the things become routine. Here it is argued that the whole life of a person is counted. I simply think, life is divided in various threads. You do something new and a new thread is created. Its along a single thread that you may measure your perception of longevity. If you do something routine then it seems to be fast to you as it becomes routine.

Also I remember a link on HN that explained how time virtually stopped for Near Death Experiences.

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.

About 15 years ago (that long already? ;)) I saw a documentary state that scientists had done studies showing that time perception could be manipulated by changing their temperature. The warmer it was, the more slowly time seemed to pass. The colder it was, the faster it seemed to pass. They hypothesized that since people's core body temperature dropped as they age, that it could be a factor in why time seemed to pass faster as we age. For some reason I've always favored this solution.

For anyone interested in how humans conceptualize time and what effects this has on language, I highly recommend "Metaphors We Live By" by George Lakoff and Mark Johnson. Truly one of the most interesting books I've ever read.

For a brief overview of the approach they take to the problem, the Wikipedia entry for conceptual metaphor is a good start: http://en.wikipedia.org/wiki/Conceptual_metaphor

With it being published in the Journal of irreproducible results i assume this is a joke, right? Still, I think the hypothesis is not correct. Time seems to run faster when you are occupied. People get more busy after their 20s so i guess that's why time seems to fly. If i can judge from myself, time seemed to run pretty fast on a 9-6 job (i was there 20-26). Working independently (26- ) has definitely made my days longer, much longer, sometimes irritably so.

Marcel Proust wrote a profound series of books that investigates memory, personal change, and the subjective feeling of time called, "In Search of Lost Time." He had an exceptional memory and recalls his own perceptive and idiosyncratic feelings starting from early childhood. Some of his observations are universal though, and you'll be delighted when he helps you remember them for yourself.

Another thing this would neatly explain is why it seems harder to make new friends when you get older.

With someone I meet at 15, when I'm 20 i'll have known them for 5 effective years. If I meet someone new at 30, on the other hand, I won't have known them for 5 effective years until I'm 40.

This is math describing the effect not the cause, so the title is inaccurate and misleading.

off topic:

why is equation rendering still broken on the web?

http://everything2.com uses pre tags, wikipedia uses rendered png images.

is this just another ie work around or have we really not implemented a standard yet.

googled it myself http://en.wikipedia.org/wiki/MathML

edit: thanks mbell! mathjax looks great

project to get mathjax working on wikipedia ~> http://en.wikipedia.org/wiki/User:Nageh/mathJax

breakdown of mathml support ~> http://caniuse.com/mathml (only firefox and safari)

Also see http://www.mathjax.org/docs/2.0/tex.html

Used on the most math heavy site I frequent: http://electronics.stackexchange.com/

Mathjax does not work great. It is slow, bothersome, and easily broken.

LaTeX and the web are in essence incommensurable.

Don't worry. Its probably going to get get excruciatingly long at the end.

Seriously, its the thinking too much about the past and the future that lead to this perception.

You probably just thought about it a lot less when you were young.

Not sure but according to Von Bertalanffy, brain "frequency" tends to slow down with age anyway. The same amount of perceptive events are spread onto longer periods of time thus appearing speeding up.

My grandfather, who died last year at 93, used to say that when you were 2 going on 3, that was 33% of your life. At 49 going on 50, though, that's 2% of your life. 33% goes a lot farther than 2%.

I wonder what the formula would look like if it took into account the fact that life expectancy is increasing. According to people like Ray Kurzweil, it's increasing exponentially.

He claims so, but he is not removing any parameter... And why such a (rather trivial) linear model is considered as a proved theory?

my own subjective data:

in my childhood, a day seems to go pretty slow, probably because of just "messing around" tends to get boring. However I never felt the years as passing at a different rate than they do now (in my mid 30's).

I'm the type of person who "looks to the future" however so maybe if I was past-oriented I'd feel different.

Because you heart rate decreases. Other internal clocks also seems to be reflected with the age.

I always liked to think that our perception stays the same - it's just that time is speeding up.

Has anyone here managed to defeat this effect somehow? How did you do it? Meditation?

This is why I love HN. The comments are better than the article.

Because you get slower.

No real evidence beyond this theory.

More likely, as peoples' lives get more complex, and as they get older and more able to separate life into compartments, the individual compartments get less time and therefore time seems to go faster. Children have one "life thread". Adults have a ton of them for various relationships, interests, and aspirations. For one example, since most people only get to spend about 2 weeks per year in the "travel thread", time from that perspective seems to go 26 times faster. If you have a summer house and show up in June and it feels like the last time you were there (September last year) was yesterday, that's what's at play. In that thread, it was yesterday.

Minute to minute, time seems to be going at the same rate. It's when you step back and take a macro perspective that there's a difference, because our lives accumulate complexity that we couldn't have imagined when we were children. Because our lives are a lot more complex, there are contexts in which 5 years isn't an eternity in the way it would be for a child, so from a macro perspective, long time durations aren't nearly as long.

Here is my take on the question...

1. Kids are bored too often so time seems to take forever.

2. Career life and building a family is so busy that time flies by.

3. Retirement and empty nesting seems to go by fast because you think more about your pending demise and also have nothing to show for your life day after day (career goals ETC.)


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