There is a sort of white-blue flash on the screen that stays for a second. So there is feedback. It might also be size sensitive, so the smaller the things are you noticed, the smaller the flash. As you often have your whole party perform the same check only half a second apart, the check bar might obscure the thing you just perceived. And perception checks often happen when you move your party and have your screen somewhere else, so you struggle to find the Pos1 key on your board, when you hear the sound cue (which only plays when the check failed or succeeded) just to come back to see that it already disappeared. Your attention might also be diverted elsewhere.
When you succeeded with the check you might even see the new thing, but have no idea what it is or what it actually does. So this is a button, what is it for? Is it a pro-active trap? The vent on the floor, I assume it is a trap? It does not help that you have to right-click it to see if it is a trap, and disarm it that way. So in case of the button there is nothing more that your awesome perception check tells you.
In BG2 the perception check or clicking on it with the mouse would have prompted a text like. There are a couple of wires connected to the button leading to the gargoyle heads at the far end of the room. There is an electric humming noise coming from the wires. Upon clicking it you would get a text like. The electric humming noises stopped. The switch seems turned off now.
Any feedback about the environment can only be described as awful at the moment.
