Most people will be honest. And incorrect. Honest incorrectness isn’t the same thing as lying, but it amounts to the same thing when you’re talking about witnesses to a specific event. A relative minority will limit themselves to reporting what they actually saw, not things that they have filled in by assumption, or memories contaminated by too much exposure to other points of view. Of that relative minority, even fewer will be the kind of person who, by natural inclination or possibly training, has the capacity for noticing and retaining a large amount of detail in a limited amount of time.

The point being that once events pass into memory, they already have a tendency to begin to become muddled and cloudy. It can be more of an art form than a science to gain an accurate picture of what transpired based upon eyewitness descriptions—and that’s for a matter of relative unimportance, purely a matter of fallible intellect, with no deep personal or emotional issues involved.

Throw emotions into the mix, and mild confusion turns into utter havoc. Take that same fender-bender, make it an accident between a carload of neoskinhead types and some gangbangers at a busy crosswalk in a South Side neighborhood, and you’ve got the kind of situation that kicks off riots. No matter what happens, you probably aren’t going to be able to get a straight story out of anyone afterward. In fact, you might be hard-pressed to get any story out of anyone.

Once human emotions get tossed into the mix, everything is up for grabs.

The second reason things can go unnoticed in the middle of the big city is pretty simple: walls. Walls block line of sight.

Let me rephrase that: Walls block line of involvement.

The human animal is oriented around a sense of sight. Things aren’t real until we see them: Seeing is believing, right? Which is also why there are illusionists—they can make us see things that aren’t real, and it seems amazing.

If a human being actually sees something bad happening, there’s a better chance that he or she will act and get involved than if the sense of sight isn’t involved. History illustrates it. Oh, sure, Allied governments heard reports of Nazi death camps in World War II, but that was a far cry from when the first troops actually saw the imprisoned Jews as they liberated the camps. Hearst had known it before that: You furnish the pictures, and I’ll furnish the war. And according to some, he did.

Conversely, if you don’t see something happening, it isn’t as real. You can hear reports of tragedies, but they don’t hit you the way they would if you were standing there in the ruins.

Nowhere has as many walls as big cities do, and walls keep you from seeing things. They help make things less real. Sure, maybe you hear loud, sharp noises outside some nights. But it’s easy to tell yourself that those aren’t gunshots, that there’s no need to call the police, no need to even worry. It’s probably just a car backfiring. Sure. Or a kid with fireworks. There might be loud wailing or screams coming from the apartment upstairs, but you don’t know that the drunken neighbor is beating his wife with a rolling pin again. It’s not really any of your business, and they’re always fighting, and the man is scary, besides. Yeah, you know that there are cars coming and going at all hours from your neighbor’s place, and that the crowd there isn’t exactly the most upright-looking bunch, but you haven’t seen him dealing drugs. Not even to the kids you see going over there sometimes. It’s easier and safer to shut the door, be quiet, and turn up the TV.