It seems fitting to round the week out with this because I’ve been writing about brain chemistry and function recently. This is a really interesting question because you’d think that there are a lot of different factors in this, but it really just comes down to one thing. How good something feels is inversely proportional to how much time elapses between you doing something (a button pressed, a mouse moved, etc.) and you seeing the results of that something on screen. The less time there is between pressing a button and seeing a response, the better the game feels.
Humans have an innate sense of time passing even when it comes to fractions of a second. Our brains can’t consciously keep up, but that isn’t the part of the brain that determines whether something feels good. For most people, it takes around 170 milliseconds for their brains to register that they’ve performed some sort of action like pressing a button. The sensation of movement, the feel of the material against the skin, the temperature of the plastic, all of these elements take about 170 milliseconds to register in the average human’s brain after they press a button on the controller. This means that the brain is going to expect a reaction to this input. The earlier you see a response, the better (and more responsive) the game feels.
This 170 milliseconds must be amortized over several factors - network lag, display lag, and processing time. Network lag is time your gaming device must spend waiting to hear back from the server, and cannot be excised. In addition to the possibility of network lag, there’s display lag. Even if the console or PC is ready to display something, it still takes a non-zero of time for the signal that leaves the console to be shown on the monitor or television. In the best gaming displays, this process takes ~20-30ms. Finally, there’s the amount of time it takes for the CPU and GPU to process what to display and then send that data to the screen. Generally, the top end threshold of what feels “good” is around 250ms. Any longer than that and the game will feel probably sluggish and unresponsive.
There’s a second half to this, however. Just because we know that we have to display something within this time window doesn’t mean that we can just display anything and be done with it. Human brains also need a sense of continuity of what they see. If something just vanishes without warning and appears elsewhere, even if it happens instantaneously, it feels weird. This is why we almost never see instantaneous teleportation without any sort of visual effect to accompany it - the lack of continuity makes the brain subconsciously feel like we missed something even if we haven’t. This means that we need to acknowledge the input in a way that smoothly transitions from whatever we were doing before the input to the new thing, even if that new thing is to play a voice saying “I can’t do that right now.”
In order to create this sense of continuity, we generally use some combination of animations, sound effects, visual effects, and so on. Each of these takes place over some amount of time to ease the player into what’s about to happen… but it cannot take too long, or else it won’t feel responsive. And that’s the general rub - we want smooth animations that read well, but that takes time, and we have a very limited amount of time available before the player’s subconscious brain gets tired of waiting for the player character to jump. It’s a delicate balancing act that requires skilled animators, vfx artists, sound designers, and engineers to get the game into the sweet spot for reaction time in its worst case scenarios.
Got a burning question you want answered?