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Notes -
Medical/neuroscience question for those of you with domain expertise.
It's well-established that the "clock speed" of a person's brain runs very quickly in their youth and slows down as they get older. This is why children's perceived sense of time is so much longer than adults': I'm sure you remember sitting in the back of class in primary school willing the clock to tick just a little faster, but nowadays you sit down at your desk at 9 a.m. and before you know it it's already lunchtime. Many people independently report a sensation of perceived "slow motion" when they find themselves in intense life-or-death situations, which is likely due to the same effect: your body produces massive amounts of adrenaline which temporarily jacks up your brain's clock speed.
Years ago I noticed a potentially related phenomenon. Back when I was a much more avid listener than I used to be, I would often listen to music first thing after waking up, before I'd even finished drinking a cup of tea. I noticed that songs I listened to at this time of day would sound like they were being played at a higher tempo, compared to listening to the same song later on when I'd woken up fully. My theory is that, as my brain hasn't fully woken up yet, its clock speed is marginally reduced (compare an old computer which runs a little slowly for a few minutes after a reboot), causing my perceived sense of time to temporarily speed up until I've fully woken up. The effect is subtle enough that I wouldn't really notice it unless being exposed to a stimulus whose perceived duration I'm already familiar with (i.e. a song I've already heard). And sometimes I get the opposite effect, where a song I've heard before sounds slower than I expect it to. Maybe this is a product of my brain's clock speed having increased, if I'm exerting myself physically?
Is this theory in any way neurologically plausible?
I've noticed a different one recently. The Doppler effect is caused when a moving object emits waves, and the position of the object (and hence the changing position of the source of those waves over time) causes the wave's perceived frequency to change over time. The pitch of a motorcycle engine appears to rise as it drives towards you, then falls as it drives away from you; the light of stars moving away from the earth exhibit a redshift.
On Saturday morning I woke up at 8 a.m. to run a half-marathon. I was tired and hungover, and listening to a favourite album I'd listened to several dozens of times before. In addition to changes in perceived tempo I described above, I noticed certain points in the album where the music actually sounded out of tune. (For reference, I have perfect pitch and can reliably identify the pitch of an individual note, play a song by ear or identify the key of a piece of music.) This definitely wasn't an error on the part of the artist, nor an encoding artefact (it's the same set of FLAC files I've been listening to this album on for nearly a decade, and I've never noticed anything sounding out of tune before). Any disruptions to perceived tonality had dissipated by the time I got to the halfway mark and began my return journey. This suggests it's a psychoacoustic effect caused by fatigue or being hungover.
The "changes to perceived tempo" thing is straightforward: reduced neural clock speed -> time seems to pass faster (and vice versa). But this change in perceived tonality is much odder. Why would a reduced clock speed affect the perceived pitch of a note, in addition to its duration? A computer that's running slowly takes longer to carry out computations (up to and including the display's frame and refresh rate), but it doesn't systematically make every pixel a few shades darker. And it isn't even happening globally: it's not as though the song was recorded in E major, but subjectively sounds as if it was recorded in E-flat until I've woken up fully. It sounds out of tune, meaning my brain is misinterpreting the pitches of certain notes but not others.
Any ideas?
I think most of this is just memory. To kids, things are newer, so more is memorable. Looking back a day packed with memories will feel longer than an unmemorable one.
They've actually specifically tested the adrenaline effect. Skydivers given watches did not feel the seconds were passing any slower, but then looking back they did feel that time slowed down. Skydiving is memorable so this also points to the memory hypothesis.
That said, I have noticed differences in clock speed too, and think you're onto something. Dead by Daylight skill checks are purely timing-based, and at night it feels like they move at least double as quickly (half as much time to respond) as in the morning for me.
I assume you mean because you're more sleepy at night compared to the morning?
Yeah and generally worn out. The next morning skill checks feel like they're moving in slow motion.
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I had no idea "clock speed" was different in youth vs old age. I always thought the reason youngsters experience time differently than older folk is because of humans' (or animal brains, really?) general logarithmic perception of stimuli.
In Psychology class, they taught us as a general rule that you would need to add 10% of extra weight to your weightlifting to feel a difference, as opposed to a fixed amount like 10 lbs. That is to say, the human brain reacts to percent-increases rather than fixed increases.
As such, 1 year is a long time to a young person ("high percentage of their life so far") but a short time to an old person ("low percentage of their life so far")
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One possible explanation that comes to mind is that this is some neurological effect of variation in your glucocorticoid level, which exhibits circadian fluctuations. Cortisol for example, probably the most prominent and well-known glucocorticoid, typically peaks when you wake up and then decreases throughout the rest of the day.
Obviously there's not too much research on the phenomenon you're describing but this study measured the effects of glucocorticoid levels on pitch-discrimination, and it turns out there is a positive correlation between the two, with higher glucocorticoid levels leading to higher perceptual sensitivity regarding pitch. I would not be surprised if the out-of-tuneness you're perceiving in the morning stems from exactly this; in the early morning when your cortisol levels peak you may have a greater sensitivity to slight microtonality or pitch fluctuations in the music you're listening to. Hell your brain may even be perceiving how wrong most music inherently is, since strictly speaking every note in equal temperament tuning is slightly out of tune and we only use it because trying to get perfectly tuned ratios between notes creates annoying enharmonic gaps. Also most music, apart from those that use pure sine waves, will possess many timbral harmonics and inharmonics that are not in tune at all.
This seems like the most likely answer.
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The Doppler effect occurs due to wave peaks/troughs arriving at your sensor faster or slower. It’s only going to be affected by starting frequency and relative motion.
I think it’s more likely that you have some other sensory interference, like rushing blood or ringing, which changes during the day. For all I know the water content of your skull changes its frequency response. If your sinuses are stuffed you’re gonna get some weirdness.
I know the phenomenon I'm describing isn't actually caused by the Doppler effect, I was just using that as an example of changes to perceived pitch.
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I don't think your clock speed hypothesis explains why you're hearing things differently. I'm not extremely well-versed in the mechanics of auditory perception, but I don't see how differences in the subjective experience of time would impact the immediate experience of an auditory phenomenon. Perhaps you'd remark that an entire album was over faster than you anticipated, but literally perceiving individual songs as faster-tempoed seems unrelated. I don't believe the auditory cortex communicates much with the time-keeping areas of the brain, though I'm open to convincing.
Also, it was my understanding that older adults perceive time as faster because their lives have less novelty, more routine, and that individual years are lower in proportion (i.e. 1 year as a 5 year old is 20% of your life, 1 year as a 50 year old is 2% of your life). I'd be very interested in seeing the research discussing neurological explanations.
Another thing that crossed my mind is the cortisol awakening response. It seems like it could be worth investigating, even if I have no plausible hypothesis for how it could be affecting you.
No clue why you are experiencing different tonality. I wonder if it has anything to do with altered memory states after waking, where you're hearing the song and perceiving it sounds differently than you remember because your recall ability is worse, for example. Have you ever experimented during these instances? Next time it happens, maybe pull out a piano and see if you're hearing those tones differently, too.
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