With this week’s discussion, I am tapping back into the outflow of the 2008 Game Developers Conference. One of the lectures, “Playing to Lose: AI and Civilization,” was given by Soren Johnson, the lead and AI programmer on Civ 3 and 4. The main premise of the lecture was that there exists a spectrum ranging from “Good AI” to “Fun AI”. (Read my notes from the lecture.)
“Good AI”, according to Soren, is one that is designed to take the place of a human player. It is meant to play as well as possible, using all the same tactics available to a human player. In fact, this form of AI is most likely to appear in symmetrical games – where all players are in similar roles and maybe even using the same units. We can measure the AI’s performance through specific metrics of score, ability to win, or any other objective mechanism. In theory, it is meant to be able to pass the Turing Test — at least in the framework of the game. His example of one of the most pure types of “Good AI” was that of Chess.
On the other side of this range is what Soren termed “Fun AI”. In this case, the point of the AI is simply to provide something entertaining. That’s it. His token example was “Desktop Tower Defense”. The entirety of the enemy AI is pathfinding. All the enemy units are trying to do is move from one side of the map to the other (but they do it in a menacing way!). The game experience is based on the player trying to prevent them from doing so.
We aren’t expecting much out of those enemies. They aren’t using our tactics or even our units. As such, any performance has to be measured strictly by our own ability to play rather than the ability of the AI to challenge or defeat us. The only test of the AI is subjective based on how much entertainment value it provides. And of course, such a lack of even an attempt at performance means that the Turing Test doesn’t even apply.
Playing To Lose  Soren Johnson Game Developer’s Conference 2008 Download ZIP (7.5 Mb)
Having defined these theoretical bookends, Soren proceeded to spread various games across this spectrum. Starcraft was tilted more towards the “Good” end, Heroes of Might and Magic V was on the “Fun” side. Using the criteria that Soren laid out, most games could be arranged on this continuum. Of course, he placed Civ 4 right in the middle. Much of the rest of the lecture addressed design decisions that they made in order to facilitate that blend of “good” and “fun”. And that is where I started feeling something was wrong.
Is There Something More…?
While I appreciated what he was trying to convey, there was something about this approach that didn’t sit right with me. Perhaps it was simply the semantics of the word choice that bothered me. I refused to admit that “good” was necessarily the polar opposite of “fun”. I can honestly say, for example, that I have often thought that a game was not “fun” because the AI wasn’t playing well (i.e. “good”). (Imagine playing a Chess opponent that uses a similar approach to the AI in “Desktop Tower Defense”… I can’t see how that would be fun at all.) The crux of the matter is, in Soren’s definition, being “good” and “fun” is not possible. Obviously, this is not exactly what he intended to convey.
Soren is not the only one who has broached this subject, however. I have personally been involved in plenty of discussions with other game designers and AI programmers about exactly this issue. Often, there is one side whose arguments reduce to the dogmatic tenet:
“We are not in the business of creating smart [good] AI, we are in the business of creating an entertaining [fun] experience for the player.”
But is that necessarily true? Are these ideas necessarily mutually exclusive?
Can We do Both?
In the past, the creed expressed above was sometimes a smoke screen for the fact that AI programmers had to “cheat” in order to create the coveted “illusion of intelligence”. We couldn’t even approach creating smart/good/realistic AI — since we were going to have to fake it anyway, we obviously had to focus simply on making it “fun”. That was our only charge at the time. Lately, as processing power has increased, so have the expectations of the abilities of the game AI. Ironically, depending on the game genre, it is now becoming harder to fake the expected level of intelligence without actually building that smarter system. So where does that put us on Soren’s “good vs. fun” scale?
This brings me to my discussion topics for the week. Is it possible for an AI to be both “good” and “fun”? What are some examples of this? What are some examples of where a “good” AI would not be “fun?” Would it be better if this graph had been done on two axes rather than one? If so, what would this look like? “Good vs. Bad” plotted against “Fun vs. Not Fun?” Most importantly, are we as game developers – designers or programmers — shorting ourselves and our players by holding to the premise that good, realistic AI does not make for an entertaining experience? Or maybe it’s just that our approach to solving this problem is flawed?
I certainly hope that this discussion will be challenging [good] — and yet still be “fun” to talk about. Let’s hear it!