[HN Gopher] The speed of sight: Individual variation in critical...
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The speed of sight: Individual variation in critical flicker fusion
thresholds
Author : bookofjoe
Score : 24 points
Date : 2024-04-03 12:20 UTC (10 hours ago)
(HTM) web link (journals.plos.org)
(TXT) w3m dump (journals.plos.org)
| JohnMakin wrote:
| This comes up in an ancient and often heated discussion a lot on
| game boards as to the "optimal" FPS to have in a game - many
| proponents saying anything under 100 FPS is "unplayable" for
| them, and another group saying basically anything over 60 is
| either not noticeably perceivable to the human eye, or barely
| noticeable.
|
| I'm starting to see the pop-science-gamer-journalism
| interpretation of this study as being "study proves some humans
| see at different FPS" and all the 100+ FPS gamers being like
| "AHA! Told you!" when really the results of the study support the
| ~60 fps conclusion that's been mainstream for a while (if I'm
| interpreting correctly). I think the science here is pretty clear
| - there is a variation in human visual temporal resolution, and
| this paper's a bit over my head but if I'm understanding
| correctly it isn't much (at least in this sample size and the
| gamer context - I'm aware they concluded the variation was large
| between individuals).
|
| TLDR if you're fussing that you're "only" getting 90 FPS vs 120
| or whatever, and genuinely feel like it's affecting your
| performance - don't worry, seems very similar to the audiophile
| stuff to me. I think that there are probably big outliers in this
| range (thinking specifically professional baseball players), but
| perhaps the "perceived" difference is because if you have 130 FPS
| your _average_ framerate is likely to always stay above your
| perception, and maybe at 70-90 it will occasionally dip below
| that threshold, causing you to perceive a difference.
| Terr_ wrote:
| To complexify things a bit more, there's also a difference in
| testing/implications between:
|
| 1. Someone can detect a difference between rate X and Y.
|
| 2. Someone can detect that X is lower than Y.
|
| 3. Someone receives information better when increasing from X
| to Y.
|
| It's self-evident that there are values of X and Y where those
| are all true, but it's not certain that they will become false
| at the same conditions.
| causi wrote:
| Gamers have testably higher in-game performance at higher
| framerates.
|
| https://www.youtube.com/watch?v=OX31kZbAXsA
| kanbankaren wrote:
| The US military has done research on refresh rates to find
| out the optimum refresh rate for pilots and their conclusion
| was the same. Beyond 60fps, there is not a benefit.
|
| There was another research which discussed about a latency in
| the brain of around 15ms. Even if the visual system could
| detect a change, not much could be done with that change due
| to the inherent latency.
| 082349872349872 wrote:
| Note that hearing and touch have higher "frame" rates.
| thfuran wrote:
| >There was another research which discussed about a latency
| in the brain of around 15ms. Even if the visual system
| could detect a change, not much could be done with that
| change due to the inherent latency.
|
| That claim does not support that conclusion. 15 ms is
| roughly the frame time at 60 fps, meaning framerate
| potentially accounts for a significant and reducible
| portion of overall latency.
| causi wrote:
| A 45,000-pound airplane has a slower response time than a
| cursor on a videogame.
| kanbankaren wrote:
| The research was in relation to HUD for fighter aircraft
| from what I recall. Nothing to do with how the aircraft
| responds rather identifying targets on screen.
| drjasonharrison wrote:
| It's a bit difficult to draw reliable conclusions from this
| critical flicker fusion paper to the entire visual field and to
| the detection of changes in position or appearance.
|
| My take away from the paper is that there is variation in the
| CFF across individuals for foveated visual targets that are
| much brighter than the surround. It remains to be seen the
| effects of visual targets that are dimmer, lower contrast,
| colour, and peripherally placed.
| bee_rider wrote:
| I'm quite happy to have grown up in the n64 era, totally happy
| with 30fps. And you can get some sweet effects and high
| resolution on a cheap card at 30fps.
|
| OTOH, some games seem to add, like, a frame or two between
| input and response? Whatever it is, it feels really annoying.
| But I've played plenty of games that feel perfectly tight and
| responsive at 30fps so I think there must be something else
| wrong. I'm sure it could be fixed with a higher frame rate, but
| I'd rather not resort to that.
| tithe wrote:
| This is fascinating. I often wonder about the different "clock
| speeds" of various functions in the brain and the mechanisms in
| play to keep these functions in sync.
|
| Tangentially, I wonder if the brain's "FPS" (sample rate?) in
| hearing and processing audio differs between individuals in a
| similar way.
| bombela wrote:
| If I get that right the test is a single blinking led. I think
| it's much harder than detecting a flickering motion.
|
| I can definitely tell 30 vs 60 vs 120fps when moving a mouse
| cursor for example.
|
| For flickering LED light bulbs (120/100hz) I usually notice
| during a rapid head movement that something is off. Or that the
| light is blindly bright to look at while at the same time what it
| illuminates doesn't feel as bright as it should be. I learned to
| assume that it means the light is flickering, because I can
| easily use my phone to record a slow motion video for
| confirmation.
| zamalek wrote:
| Yup, flicker fusion is for the _bare minimum._ My second-hand
| knowledge is that we can reliably identify a single flash at
| roughly 1 /900s. We are even subtly conscious of single
| photons.
|
| What I can say for certain is that the difference 75FPS and
| 60FPS is the difference between enjoying VR and leaving your
| lunch on the floor.
| IAmGraydon wrote:
| It's not testing flicker fusion threshold unless it's
| activating the exact same spot on the retina each time it
| flickers. When you move, the spots are distributed along a path
| across your retina.
| snailmailman wrote:
| I hate those light bulbs. They blink at I think 120hz? Idk
| maybe that saves energy as half the time the light isn't on.
| And maybe most people can't tell.
|
| As an object moves in sunlight it looks smooth to your eyes,
| but under a blinking light you only see the motion during
| moments that get lit up. This is much more obvious for faster
| motion.
|
| I'm not 100% certain but I think this sort of lighting triggers
| bad headaches for me. I get bad headaches some times, and I've
| always been pretty sure the lighting was why but I've only
| recently started confirming with my phone that all those places
| where I get headaches use blinking overhead lights for the
| entire room. More and more places around me have adopted it and
| it's awful. I have tons of clips in my phone now of random
| locations in slow motion, many of which have these lights. I
| can't walk through a store that's using them for very long.
| smodo wrote:
| Very possible. I've suffered a brain injury that has made me
| more aware of this kind of discontinuous input. It is
| definitely more taxing for the brain.
|
| LED lights with poor drivers are a rudeness to me now.
| bombela wrote:
| 120Hz US, 100Hz EU. It flickers at twice the main's
| frequency. It is because the LED drive/power supply
| electronics is too cheap to have enough capacitance to
| maintain the LED powered while the alternating voltage is
| crossing zero.
|
| I used to get headache from flickering CFL lights in store
| when I was a kid. Those days only the worst LEDs make me
| uncomfortable.
|
| Some LED bulb will flicker with a really sharp cutoff, they
| are the worst. Many will flicker, but not down to zero light.
| This does make a difference.
| aimor wrote:
| Yes, I think that the light being stationary is an important
| distinction, though it's a good thing to control for because
| motion complicates things.
|
| I came to the comments here because of a flickering effect
| (different from what they're testing for) I often observe: the
| tail lights of cars. Sometimes when I move my eyes (not my
| head) _very_ quickly I will see a dashed trail from the red
| tail lights of certain cars (I 'm assuming they're pulse
| modulating for some reason). I've been thinking about this in
| terms of the often-cited phenomena where our brains 'black out'
| our vision briefly when moving our eyes. I think this (brain
| 'blacking out' our vision) is not what happens, and some others
| have similar evidence:
| https://www.science.org/doi/10.1126/sciadv.abf2218
| bombela wrote:
| I don't think I see a dashed trail, but I will pay more
| attention. I mostly find that many modern car LED lights are
| flickering very obnoxiously. And it is worse during motion.
| aidenn0 wrote:
| This shows the flicker fusion as bottoming out just over 60Hz;
| this conflicts with the fact that a large fraction of the people
| I know can see flickering in fluorescent lights and CRTs at 60Hz.
| One roommate I had could tell if my monitor was below or above
| 72Hz (this is for a static image, so unrelated to FPS).
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