When it comes to video games, A.I. have become an important and vital role, and for some games, the A.I. make the game into what it is. This also meaning that solid, intelligent, and realistic A.I. have to be tweaked and worked on, for a long time, if game developers wish to create the best A.I. out there. So, with that in mind, I thought I would share the types of game AI that exist. Types of Game A.I. : Scripting - Without question the most used game A.I. used to day. Think of it as an "If... then..." statement. If the player ducks behind a wall, wait four seconds and throw a grenade. Random Scripting - A type of scripting that adds more variety to gameplay. Think "If... then... or..." If the player ducks behind a wall, wait four seconds and throw a grenade, or rush the wall guns blazing, or find higher ground and cover to shoot over the wall." Behavioral or Character Based Scripting - Random scripting with character types. If a soldier NPC is deemed defensive its likelihood of doing a particular action could be tweaked as 25% of grenade attacks, 5% of rushing, 70% of taking cover. If the NPC is aggressive, 40 % grenade attaches, 45% of rushing, 20% of taking cover. Character based scripting is often adjusted throughout game balancing. Situational Awareness - An advanced trait of A.I. scripting that improves a player's sense of immersion. By making scripted actions appear more dynamic and realistic, it adds a dimension of believability. Examples may be subtle effects like brushing a hand along a wall while walking past it, or more complex problem-solving behaviors like an NPC escaping from a trap set by the player using objects in the game environment. Pathfinding - Getting an NPC from point A to B. 3D terrain and cover are huge A.I. dilemmas in modern A.I. programming. You also have to keep in account where the player is, is he firing, should the NPC fire when he moves, or go as fast as possible. Then at the end, did that look real. Scripting tells the NPC where "B" is Pathfinding gets him there. Emergent - Where the game actually learns from your actions. Black & White and Nintendogs are good examples (although Nintendogs is pretty scripted). Rubber Banding - Is a nickname A.I. that's used to boost the competitive feel of the game. In a racing game when the A.I. is slipping behind, the NPC driver receives speed boosts and better handling unavailable to the player to remain competitive. It increases tension. Burnout and Mario Kart both use rubber banding in races to keep them competitive. This is not exclusive to driving games. It's used in many sports games or skill based games.
http://www.giantbomb.com/artificial-intelligence/3015-218/