Game Artificial Intelligence

About a year ago I coauthored a paper on multiplayer video game Artificial Intelligence as part of one of my grad classes. I wouldn’t feel right with publishing any real substance from the paper without permissions from my two coauthors, both of whom I have not been able to contact. I do, however, feel comfortable throwing up the opening paragraph from the rough draft, as I think it set the mood for the paper and for this blog post.

You finally enter the area known as the Hunting Grounds with your virtual character. Your friends had told (warned) you of this place: the dangers you would find and the treasures you could discover. Despite knowing your character might fall prey to many of the monsters that inhabit this area of the game you feel calm as you run a last check of your equipment and arm your bow, ready to stalk your first prey. And then he comes into view – you can feel the game controller grow slick in your hands as your palms start to perspire, your heart races, and it becomes difficult to swallow. You have just come across a player killer. A player killer, or PK as they are commonly known, is another human player who spends their time hunting other players instead of the in-game creatures, and this one has just spotted you. You curse aloud.

I think just about everyone who has played an MMO with player killing allowed can empathize with the above paragraph. Even in games where human against human combat is separated and you have nothing to lose, such as in Destiny with the Crucible matches, you can still get that anxiety when faced with a human opponent. Yet you will happily go against a computer controlled boss over and over without flinching, even if that thing can kick your butt to tomorrow and back again.

I see this as the problem with game AI. The purpose of in-game artificial intelligence is to have the computer controlled entities appear intelligent. It is not true artificial intelligence, just the appearance of it. For game play this is fine and I would not suggest the need for actual intelligence in a video game on the part of the characters. What I would suggest is a change in the purpose of artificial intelligence engines in video games.

Game AI needs to become about creating a realism in the characters, to make them more believable. This doesn’t mean they have to be more intelligent, but it does mean that their actions, or inactions, have to make more sense for whatever type of entity it happens to be. Allow me to give some examples.

1a. You are wandering in the forests and a wolf attacks you, snarling, barking and howling.

or

1b. You are wandering the forest when you hear the howling of a wolf in front of you a moment before coming face to face with it. It stands, ears flattened and teeth bared snarling at you from about 10 feet away. Before you have the chance to sprint the distance and attack, three additional wolves leap at you from the back and sides.

2a. You are sent on a mission to track down and kill a bandit who has been hunting the countryside for weeks. You set out and find his holdup, entering the dark cave you are confronted by not only the bandit, but five of his men who all attack you.

or

2b. You are sent on a mission to track down and kill a bandit who has been hunting the countryside for weeks. You set out and find his holdup, entering the dark cave you realize, as an arrow hits you from behind, that the bandit has been tracking you.

In each scenario above “a” is pretty much how every AI engine handles such an encounter, but I’m betting “b” would make you jump a little bit in your seat the first time it happens. And the next time? Maybe not, but the next time should not occur the same way. Oh, maybe a pack of wolves has kind of limited set of hunting actions (yet effective!), but people… Now people are unpredictable.

Any intelligent species should be a bit more unpredictable. That is where I think game AI needs to move towards – more believable behavior through both what is expected and unexpected in the characters. Because as the player you should have occasion to both jump from your seat and to curse aloud when playing a video game.