Short history of ingame AI

 Apart from automation tasks in a factory, there are major attempts available since the 1980s to build intelligent ingame characters targetted towards videogames. This subject seems to be easier to solve because in a videogame all the information are known.

Typical ingame AI in the 1980s was realized with Finite state machines. Especially the pacman game is using this single technique to control the ghosts. Another famous approach is depth first search used in board games likes chess and Nine men's morris.

Both concepts have major disadvantages. A finite state machine is difficult to program and a game state traversal in chess needs a lots of CPU ressources. Until around the year 2000 there were no improvements available. Even if finite state machine have evolved into behavior trees it was also hard to implement.

The main challenge in programming an ingame AI can be summarized as the reality gap between the videogame and the internal representation of the AI agent. A Finite state machine has a certain perspective towards the game encoded in state. For example a pacman ghost has states like attack, evade, idle, random and these states are applied to the current situation. In most cases the reality of a game is more complex than the game AI representation which causes an asynchronous situation. In other word, the game AI isn't communicating enought with the videogame and this explains its poor decision making.

To overcome the bottleneck of ingame AI created until the year 2000 the focus should be on the communication between a videogame and an ingame AI. For reason of simplication there is a virtual referee who is talking to the ingame AI in natural language. This virtual referee is the source of intelligence. He will guid the AI agent. In case of Pacman the referee might say to a ghost "move to upper left", in case of chess the referee might say "protect the center".

Such kind of textual interaction solves the former reality gap. The game AI gets a constant flow of commands from the referee and the only obstacle is to understand and execute them.

Lets compare old school ingame AI with modern communication based AI. The typical AI for a videogame before the year 2010 was realized as a software project. The idea was to encode the knowledge in the source code and make the AI smart by itself. The goal was that the AI acts independent from its environment and has all the needed knowledge and all the needed algorithm as internal software modules for pathfinding, decision making, perception and case based reasoning. Of course it was very complicated to program such an AI but there was no alternative available.

In contrast, modern AI created after the year 2010 is working with the extend mind thesis. The source of knowledge and intelligence is located ooutside of the game bot, either in the game engine, in a virtual referee or in a human operator. There is no need to encode knowledge into the AI itself but the AI is realized as parser for external commands, similar to a receiver in a RC Car teleoperation. The receiver listens to the signals and converts into action. this principle results into a minimalistic software which is much easier to realize and is more flexible at the same time.

The surprising situation is, that technically such a concept was realized in the 1980 already but it was recognized as a here to stay technology. In case of text adventure likes Zork and early role playing games, the human user was entering text commands which were executed by the game engine. So there was no AI available as a compuational engine, but there was only a parser available which executed a two word command.

Such a parser has no reality gap because it has no internal representation. The external human operator is responsible that the avatar is reaching its goal. The parser is only a command receiver.