WHEN YOU GO to the message boards for the new game Black & White, released by Lionhead Studios earlier this month, the most popular topic around seems to be crap. In post after post, the flight, trajectory, and eventual resting place of vast quantities of virtual crap is discussed in loving detail. Villagers are pelted with crap; fields are fertilized with crap; crap is produced and promptly eaten. There's evil crap and good crap. The arrival of both is occasionally greeted with dancing from local villagers. On other occasions, crap is desired but difficult to come by. Players' avatars, in the form of cows, tigers, and apes (known collectively in Black & White-speak as "creatures"), work mightily to generate it, and get nothing but gas and maybe some embarrassed looks.

Welcome to the current cutting edge in artificial intelligence.

The man who wrote the code that makes all this happen is Richard Evans, a former philosophy major and current next-desk neighbor to Black & White creator Peter Molyneux.  For the past three years, Black & White has been one of  the most hyped and highly anticipated PC games around (it'll be available on other platforms shortly). Now that Molyneux's brainchild has finally arrived, surprisingly enough, almost no one seems to think the hype was unwarranted. The game's mix of creature training, morality play, and world shaping has been hailed as the latest big step forward for the art of gaming.

The goal in Black & White is to literally remake a world over in your own image. You use your godlike powers -- a little "Hand-of-God" icon is your most direct presence in the game -- to convince the inhabitants of one of seven different primitive agrarian societies that you, and you alone, are the One True God. To accomplish this, you have to make your power felt. You perform miracles, which get more impressive as you gain believers. You can smite villagers (by dropping rocks on them, for instance) or save them (by arranging to water their crops, for instance). Mostly, though, you communicate with villagers by means of your painstakingly raised  creature, who goes into the world to perform deeds in your stead (hence the crap-throwing tigers).

While all this emphasis on training may sound similar to Artificial Life games like The Sims and Creatures, which also let you control towns and train (or torture) their inhabitants, Black & White differs in both scope and depth. The perspective zooms seamlessly from the one-on-one mode you use when you're training your creature to a god's-eye view ten miles above the planet. Perhaps more importantly, in Black & White all your relationships -- with your worshipers and particularly with the creature who is your avatar -- are direct and personal. When your monster does something good (or at least something that you want it to keep doing), your Divine Hand literally strokes it; when it does something incorrectly, the same Hand of God smacks it. Eventually -- ideally, anyway -- it grows into an active extension of your will, spreading your Word via its deeds. As a god, you're more Old Testament than Deist, more active meddler than detached clock-maker.

Ultimately, your decisions, actions, and style of play shape individual characters, villages, and societies, and eventually, an entire world. Creatures change appearance as they grow, becoming either demonic or angelic depending on whether you're a benign or malevolent god. The landsape can become a jagged Gothic nightmare or crystalline fairyland, reflecting your temperament.

Of course, in order to have this degree of responsiveness, every character in the game -- and the world itself -- must be capable of learning. Which means that to an almost unprecedented degree, the experience stands or falls on the strength of the game's AI, particularly its ability to "learn," to generate both useful and expected -- as well as unexpected -- responses to a variety of situations. So Evans and Molyneux have created villagers who must be taught to believe in and worship you. They've created creatures capable of learning in a multitude of ways, from imitation to a carrot-and-stick system. It's a neat combination of several different types of AI. The creatures run a variation the standard Artificial Life model, where a combination of simple, hard-coded behaviors are controlled by various motivations. In this case, the interactions between small sub-routines can produce higher-level behaviors that are complex and "lifelike" without having to resort to explicit coding of those behaviors. The creatures in Black & White, once trained, can seek out "bad" villagers to eat when they're hungry, as opposed to "good" villagers; the code allows them to distinguish between the two. For the villagers, the AI is more similar to what's been used in strategy games: a mix of hierarchical and group AI.  Here, behaviors are again broken down into parts, with some AI code controlling decision-making for the village population en masse and others controlling how those decisions are carried out on the individual level. "The town itself is a group mind, working out what needs to be done, and delegating jobs appropriately," Evans says. "Every time they react to something -- a friendly creature, a miracle, a house on fire -- they are controlled by a Reaction which is another type of group mind. When they dance, they are controlled by a different sort of group mind. It is these various group minds, coexisting, shifting priority over time, that give the villagers their varied behavior."

Until fairly recently, the kind of emphasis you see on strong AI in Black & White was rare in  gaming. AI coders had to fight for CPU power to make their creations go, and most games wound up sacrificing smarts for graphics. As recently as 1999, most games devoted only  .1% of  the CPU's resources to running the AI. This would be bad enough, but AI people were typically already working at a disadvantage, usually starting their work at the very end of a game's development cycle. (It's difficult, after all, to create intelligence for characters who inhabit a world that doesn't yet exist.) Over the past year, however, all that has changed. The march of Moore's Law and the increased muscle of 3-D graphics cards means that CPU power is no longer the bottleneck it once was. According to a recent article on the game development site Gamasutra, an average of 250% more of a computer's resources are now devoted to AI. And with the introduction of more flexible algorithms, work on AI can start earlier: Instead of the whole thing getting rushed in the final weeks, basic behavior gets written at the beginning and is tweaked as work continues. Maybe most importantly, the success of Half-Life and The Sims, among others, has pushed AI to the fore: Developers have discovered that smarter opponents, and smarter worlds, sell games. As of last week, Black & White is the top-selling PC game on the market right now. Something for John Ashcroft to consider -- in what other industry is the smartest kid in school also the most popular?

FEED caught up with Evans, the man behind Black & White's mind, via e-mail, and got his thoughts on a variety of topics: group minds; how creatures, villages, and even worlds can learn; the things he had to leave out of the game; and the next big thing in AI.

Next: Mark Van de Walle interviews Richard Evans.