Custom UT2004 bots are more human than real-life players

By on October 1, 2012, 3:30 PM

Programmers were tasked with the challenge of creating the most human-like UT2004 bots -- and it appears they delivered. In the competition sponsored by 2K games, the top two UT2004 bots tricked 52 percent of the judges into thinking they were guided by flesh and bone. To put that into context, the average "humanness" rating of living players was only 40 percent. This de-humanizing finding meant that some bots were judged to be significantly more human than their human couterparts.

As a long-time UT2004 player, this brought back fragrant memories of being charred to a smokey cinder by relentless "Godlike" bots with impeccable alt-fire plasma gun skills. Of course, that was the default AI. In this challenge, bots were armed with custom AI routines which actually aim to be far from perfect, giving them more human-like affect. 

"The idea is to evaluate how we can make game bots, which are non-player characters (NPCs) controlled by AI algorithms, appear as human as possible," said Risto Miikkulainen, a computer science professor from the College of Natural Sciences.

Amongst some of the interesting behaviors baked into these clever AI algorithms were grudges. Computer opponents would sometimes angrily pursue certain players of interest, often to their own detriment -- an undoubtedly human thing to do.

Other modifications included a less perfect aim while making rapid movements and a natural selection-like system where successful bots would pass on presumably beneficial abilities to future spawns, gradually improving bots and better matching player difficulty.

If we just set the goal as eliminating one's enemies, a bot will evolve toward having perfect aim, which is not very human-like. So we impose constraints on the bot's aim, such that rapid movements and long distances decrease accuracy. By evolving for good performance under such behavioral constraints, the bot's skill is optimized within human limitations, resulting in behavior that is good but still human-like.


Described as a "Turing test for game bots", the results of the contest were announced at the IEEE's Computational Intelligence and Games conference. The winning bots, UT^2 and MirrorBot, split the $7,000 prize. The "Turing Test" is Alan Turing's famous hypothesis which concludes a machine may be capable of thought when it, through a series of probing questions, produces answers indistinguishable from that of a human being.

For anyone interested, the Unreal Tournament 2004 mod and the bots themselves are available for download here.

User Comments: 13

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TomSEA TomSEA, TechSpot Chancellor, said:

Man, I love Unreal Tournament - I am definitely downloading this and checking out the bots. Thanks for the article!

Burty117 Burty117, TechSpot Chancellor, said:

I love this game, I WILL be downloading and trying this beast out

Anyone care to share what servers they regularly go on?

psycros psycros said:

Considering the attitudes and behavior of many FPS players, making a bot more human than some of them isn't that big of a feat

H3llion H3llion, TechSpot Paladin, said:

What makes one "human"

In all seriousness, this is extremely interesting.

Rasta211 said:

This sounds great, I wonder if they inputted the "Camping feature" too. Human players do that too you know. They should also include the "Drunken" player for jokes.


Wonder if the bots might be able to talk trash :P

Guest said:

Huge UT2004 fan here..still play it very regularly...though I felt the best version was the original UT (99) in terms of playability, though 2004 did bring in a lot of improvements.

I'm glad they're making smarter bots-the current AI is pretty crappy. It's a shame that they had a terrible vision for the UT franchise, could've been so much better but UT3 was a total bomb.

penn919 said:

Very interesting Article and even more interesting title.

Burty117 Burty117, TechSpot Chancellor, said:

I wish they could re-release UT2004 with updated graphics, bigger maps and higher player cap, maybe some more vehicles and a suite of modding tools like they did UT2004.

That would be the best UT to date. Sadly, the developers don't care any more

DanUK DanUK said:

That's some pretty impressive programming! Presumably this sort of thing could be ported to any game in this genre? I wonder if companies sell AI code like this?

Adhmuz Adhmuz, TechSpot Paladin, said:

Now to dig out the 5 CD Installation pack for UT2004 and I'll be playing in about an hour or so. Or it can be bought on steam for $15. Now to go get murdered by even smarter AI bots!

Guest said:

Sad fact that these "human-like" bots can only fool inexperienced players but when you put them against some pro players they will be busted in no time. I played vs them and I can tell that I rarely see human players which are as stupid as these "human-like" bots. In addition their skill level is poor, no fun.

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