Well there is a phenomenon where your brain will make sound and sight "match up" even when it shouldn't. Like if you hear and see a basketball bouncing 75 meters away, the sound should have about a 0.25 second delay. But your brain will make you perceive the sound as happening simultaneously with the ball hitting the ground, despite the fact that you could not perceive the visual and auditory sensations simultaneously. If you go further away with the ball, eventually there is a threshold where your start perceiving the delay. The auditory and visual sense would need to be somehow linked for this phenomenon to happen I'd say.

I guess it's the brains way of matching visual and auditory cues to try to make a better picture of the world. The brain is basically saying "that sound came from the ball" and you don't even need to think consciously to know that.