First off ESG Jagged is right everyone. Sorry. You're not super human you are just human.
I think what this thread is forgetting is some psychology though. I can also say that twitch muscle reactions are faster that 18 frames much faster. Anyone who has played test your might on the hardest difficulty can tell you they can push many times the buttons needed to block within just 60 frames. It's how the spinal cord sends motor function feedbacks for heavily repeated tasks. However, precision drops dramatically with this twitch sort of muscle reaction.
Without getting into any hard science I will explain why 18 frame overheads can be reactable. It's all about operant conditioning. When SonicFox did this flash game I am actually curious to know how long he played it to get the 19 frame reaction.
http://www.teyah.net/MilliaBlocker_v0.3.swf
Operant conditioning is a proven fact. Basically I think 18 frame reactions do exist based on the aforementioned.
So here's how the science I am thinking works. There is 4 different categories. Fighting games have them all. There is
positive reinforcement,
negative reinforcement,
positive punishment, and
negative punishment. I'll give a short example of what each is in terms of fighting games.
Being dealt large amounts of damage that could only be prevented at a single moment in the very short past. It leaves the person being dealt damage some time to dwell and think about what they should do next. This is
positive punishment. The opponent to the player receiving damage is less likely to repeat previous behavior because they don't want to be punished again.
Sometimes positive punishment will be ineffective over time also it may make the person receiving the punishment get a hopeless feeling and want to quit everything. (Fighting games only I hope. Don't quit life because you got 60% combo'd :c)
Negative punishment is when an opponent denies something that would have actually hit under normal circumstances. I like to call these the "hard" reads. Behavior or regular pokes and starters that normally hit on opponents get denied and "ignored". It would be that throw that ALWAYS hits after the Kung Lao combo that just got teched. Negative punishment is very powerful and creates a defensive behavior almost immediately unless the opponent is trained otherwise. Basically, any time you perform a behavior you usually do and it is immediately denied or ignored by the opponent you may notice a feeling to want to be defensive. You may also see it in other players online who throw out a heavily unsafe move that gets blocked like a boss.
Positive reinforcement is when you behave a certain way and you are rewarded for it by being able to do the combo you spent so long practicing. Like jump-in's they are a big one with untrained players. Jump-in's are heavily rewarded in this game as they are also how you maximise damage. Basically you performed a move and you got to win the game or deal a serious amount of damage. You also get a relief feeling for a little while as well as having plenty of time to think about your next move or their next move. This is the one that most every living thing pays attention to the most and it's the easiest thing to train yourself with.
Negative reinforcement is the last one and I sometimes have a hard time understanding it. So I will describe it the best I can in fighting game terms basically there is a behavior or move that is happening that your opponent is doing or you are doing. Such as a jump-in. You jump-in and the opponent uppercuts you viscously. Then you don't jump-in now your opponent doesn't uppercut you. You stop jumping in for the rest of the round or you stop jumping in as much because of the uppercut. You have now been trained by your opponent to not jump in. Like a dog.
Okay so why did I say all that? It's because behaviors in fighting games are automatic. Once they are practiced you don't think about them actively. It's muscle memory. Being in that, "in the zone", state of mind your behaviors are what
you and your opponents made them.
Example:
You spent twelve hours collectively in the lab against Raiden's overhead that is highly punishable. (I call it happy hands) You had it perform random moves and combos training recording and changed the recording every hour. You only looked for the over head the entire match and blocked everything else maybe except for some of Raiden's other over heads. You rewarded yourself through positive punishment and negative reinforcement. There was a behavior you were performing and now that behavior is much less likely to occur. Blocking the overhead got you a full combo you practiced and not blocking it made you have to restart the dummy. Getting hit by Raiden's overhead starter is now blocked at a much higher rate because you have used psychology to prevent poor behavior against Raiden. MAYBE you did what pro players do which is play against another pro player that you want match-up knowledge on a first to ten. They spent time training each other on what behaviors to be repeated and other behaviors that are now less likely to occur.
Now the 18 frame reactable overhead! You can block it on reaction because you aren't thinking about it anymore you just do it or you make a sick read like everyone else is saying. I am curious whether or not if I spent twelve hours playing that flash game I might be able to get my times down to 18 or 19 frames. It is truly random but the human body picks up on a lot of subtle cues as long as there is intense focus, a proper diet, and a regular sleep schedule.
What I just said happens only when you are in the state of mind that you aren't readily thinking about every action. All actions you are making must be "auto-pilot" or "in the zone" actions. This isn't me making up some shit. Operant conditioning exists and can be used to literally train anyone and any animal.
Anyways, that's my scientific theory on how I think hard to reactables are blocked consistently. I think there is enough psychology to back my statements here. Also, There is some good information here for you to train yourself to block anything. It's a lot of practice and a lot of
CORRECT practicing to get this self conditioning to work properly though. Also the tip that people say practice saying things out loud before you do them this is a way to snap back and forth between the "zone" and thinking about your actions again quickly while still being able to compete and react to your opponent.
Final Edit:
Whether you believe me or not I got a 19.5 reaction after I played the flash game a couple more times. Collectively, for about an hour or so. So much fucking time wasted haha.