[Filligree]

Humans can notice and characterise much smaller intervals, down to somewhere around five milliseconds.

We still aren’t capable of reacting faster than about 250. However, if you have latency of 250ms then your total reaction time isn’t 250, it’s 500.

[LocalH]

With aids, we can perceive and notice even smaller intervals. I play a lot of Fortnite Festival, which is the Rock Band-style mode added near the end of the year. This game, unlike any previous game in the genre, has "perfect" judgements for note hits. The window for a perfect judgement is something around 20 or 30ms. The game also gives you an average offset from "dead on" for each song, measured in milliseconds. Since the perfect judgement is immediate feedback, it enables players to perceive when they are just a few milliseconds off and correct for it. I regularly get average offset results of +/- 3ms or better, including plenty of 0ms average offsets (this is of course averaged across all notes in a song, which I am playing on a plastic guitar on Expert difficulty).

I'm nowhere close to the best player either, there's one player who recently got one of the most impressive full combos of the Metallica song One that could ever be done - they hit all notes without mistake, they got 100% perfect judgements, and they got the #1 leaderboard score, meaning that not only did they hit all notes within the 20-30ms "perfect" window, but they also "squeezed" overdrive activations within that window to activate and hit the first note as late as possible, and hit the first note after that overdrive activation would end as early as possible to still get it under the extra 2x score multiplier that overdrive brings.

The game genre also overcomes the relatively huge (in the context) human reaction time by providing you gems to read before the strikeline (or "now bar"), so that you can basically internally correct for your reaction time, similar to how people reading sheet music can perform in lockstep rhythm when everyone is skilled.

It's amazing what different forms of augmentation can do to help paper over the inherent shortcomings in our senses.

[mattkrause]

A key difference here is that you’re able to anticipate and plan upcoming actions, because you’re familiar with the general structure of music and/or the specific song.

Even the experts couldn’t respond to an unpredictable stimulus in 30ms; instead, they’re choosing between (say) a 330 ms response and a 340 ms one. This is, of course, still crazy impressive.

[bongodongobob]

Rhythm is a completely different beast though because you can anticipate. Most musicians would be more accurate than the average person but wouldn't do any better in a "click the mouse when the screen flashes red" type test.

[vikingerik]

Minor detail: the Beatmania game series has had "perfect" timing judgements for a long time, that's not exactly new.

[mattkrause]

“Reaction time” isn’t really a single value: it depends immensely your own attributes (age, experience, level of alertness or fatigue), on what you’re reacting to and how you react to it.

Under certain (admittedly very specific) conditions, people can view an image, categorize it, and indicate the category with eye movements, all within 120ms. Here’s one demonstration:

https://www.sciencedirect.com/science/article/pii/S004269890...