Cast your mind back to – if you’ve got them – the days of riding an ancient, rattling bus to your crumbling public elementary school where, after stopping by the filthy bathroom, you’d sit down at a desk encrusted with the class of ’76’s chewing gum. In the afternoon, you would, with luck, get to roll around a fecal matter-strewn public park or perhaps take a dip in the ominously yellow waters of the community pool. Ah, the little joys of childhood.

Not having income that isn’t sunk on comic books and ice cream, kids make disproportionate use of these government-provided goods. Fortunately, they’re at the age where a little grime and decay never hurt anyone, but grown-ups are less tolerant. We’re all adults here, at least biologically, and have probably come to wonder why all of that “public” stuff of our youth sucked so badly.

An easy response is that public schools and the like are free, and what kind of quality can you really expect from something whose price is zero? However, government-provided goods and services are, of course, not free; we’re all partially footing the bill via our taxes. Though the idea that you and I are paying good money for swimming holes composed mostly of urine makes me want to move assets offshore right here and now, the question stands. As it turns out, an answer can be found in your own living room.

The average Isla Vista student resides in a two-bedroom flat, sharing it with three other models of moral and academic rectitude. The monthly rent payment is typically divided an egalitarian four ways. Clearly, each resident is paying for the rights to their side of the bedroom in which they sleep, but what about the rest of the place?

This is where things get tricky. Logically, since everyone in the apartment uses the kitchen and living room, they must each be paying for the rights to a fraction of them. Does this translate into each individual only using an allotted area of the common rooms, or only occupying them during certain times? No, the usual arrangement is, and I quote, “We kind of all just use them whenever we want, and I guess it works out in the end.”

Notice then, the condition of the average Isla Vista living room. Even if the inexplicable piles of trash and bizarre, unclaimed objects are strewn neatly, taking a peek under the couch cushions will still cause you to launch into Rutger Hauer’s “I’ve seen things you wouldn’t believe” speech from “Blade Runner” for weeks afterward. As far as exploration of the kitchens, even the Hazmat-suited agents who cleaned out Jeffrey Dahmer’s apartment just might, in some cases, bow out.

This may be a pervasive phenomenon, but fortunately, economics has seen it before. The “free rider problem” occurs when, because they aren’t required to pay a price commensurate with their level of use, people suck more than their fair share of utility from a resource. It’s not that your roommates are necessarily mean or lazy; the flat cost structure just stimulates their behavior.

So it is with all that public junk you liked so well as a prepubescent. If you incur no additional charge to relieve yourself when a walk to the locker room is a little much, walk your dog that additional mile over the grass, be a little, ahem, messier in the restroom than you normally would, why not do it? After all, nearly everyone else will and rationally so.

The damages from uncompensated overuse are called “externalities,” a term you’ve no doubt heard bandied about in discussions of the pollution and congestion wrought by automobiles. Public goods – schools, roads, air, water – are plagued by externalities, and chances are your kitchens and living rooms aren’t, for the very same reason, entirely free of them either.

Many economic concepts seem alien at first, but a little thought can, sometimes literally, bring them home. As for an economic solution that actually prevents those used pizza boxes from piling up on the mostly-burnt couch, we’re working on it.

Daily Nexus columnist Colin Marshall was canned in elementary school for wearing a Hazmat suit to class everyday.