In video games, "AI" (artificial intelligence) is an informal term for the programming that allows game entities to make decisions. For example, the ghosts in Pac-Man are capable of navigating the maze they're in and chasing down Pacman — these abilities are governed by their AI programming.
AI design is one of the more abstruse and challenging parts of game design, as computers by definition have no intelligence — they can only blindly obey the instructions they've been given, and have no intrinsic understanding of the game world or its mechanics. An AI programmer must essentially build a brain from scratch, and furnish it with the means for an entity to understand the game world and how to interact with it. Doing this is difficult enough, and doing it convincingly — in a way that can fool or outsmart a human — even more so.
Since every game is different, there is no one-size-fits-all solution for AI — like any other game aspect, the way it's implemented is typically a design choice. Some games may choose to implement deliberately simple AI — either due to system limitations, looming release deadlines, or simply to make enemy behaviors easier for the player to understand. Other games may have greater AI requirements, such as enemy pathfinding and advanced decision making. Strategic games may require an AI to think ahead and try to predict what the player might do.
There is a second, more formal version of AI, which — according to The Other Wiki — is defined as an engineered system that perceives its environment and takes actions that maximize its odds of successfully achieving certain goals. This version of AI is more like an optimization engine than something that is attempting to create the illusion of intelligence. While it sees some usage in games — for example, the chess-playing Deep Blue
and go-playing AlphaGo — creating such AIs is generally more of an academic pursuit than a game design choice.
Finally, there is a third version of AI which has become prevalent since the start of the 2020s: generative AI, which uses a large language model (LLM) to produce human-like conversation and imagery. This, again, is closer to academic research than to video game design at the moment, but has nonetheless started to see usage in gaming — for instance, some games are using generative AI to give their characters realistic dialogue and reasoning skills. There are also Interactive Fiction games such as AI Dungeon 2 that employ generative AI more directly, using it to generate unique adventures that react to the player's actions.
For more details, see MediaNotes.Video Game AI. The Other Wiki also has an article on Artificial intelligence in video games.
Subtropes:
- A.I. Breaker: A human player behavior that confuses the AI and makes it behave stupidly.
- A.I.-Generated Economy: When the AI manages entire sectors of an in-game national economy.
- A.I. Roulette: The AI simply picks from available actions at random.
- The All-Seeing A.I.: The AI has full game knowledge when the player doesn't, allowing it to ignore things like Fog of War.
- Artificial Atmospheric Actions: Inconsequential NPC behaviors that make the world feel more alive, akin to a Flavor Text.
- Artificial Brilliance: An AI demonstrates unexpectedly intelligent-seeming behavior.
- Artificial Insolence: When an AI character can choose to disobey orders given by the player.
- Artificial Stupidity: An AI fails badly at the illusion of intelligence, often resulting in Fake Difficulty.
- The Computer Is a Cheating Bastard: The AI does things a human player either can't do, or isn't permitted to do under the game rules.
- Conspicuously Selective Perception: The AI reacts to the player, but completely ignores everyone and everything else.
- Gameplay Automation: The player can hand off control to an AI agent to perform tasks for them without their involvement.
- Gang Up on the Human: When multiple mutually hostile AIs cooperate against the human player for no in-universe reason.
- Manual Leader, A.I. Party: A Non-Player Companion AI that follows and fights alongside the player avatar instead of acting proactively.
- No Peripheral Vision: When an AI's cone of vision is unrealistically narrow, making stealth gameplay easier.
- No Sneak Attacks: When an AI is not allowed to use stealth mechanics against the player.
- NPC Scheduling: When an AI's behaviors change according to the In-Universe Game Clock.
- Perfect Play A.I.: An AI that plays in a game-theoretically optimal way.
- Rubber-Band A.I.: An AI that adjusts its effectiveness depending on how well you play.
- Secret A.I. Moves: Mechanics that are theoretically usable by anyone, but only available to the AI.
- SNK Boss: A fighting game AI that breaks the rules to challenge the player.
- Spiteful A.I.: AI entities disregard their own wellbeing to disadvantage the human player.
- Squad Controls: When AI-controlled followers can carry out a handful of predefined commands issued by the human player.
- Suicidal Overconfidence: AI entities attack the player even when it's clearly impossible for them to win.
Related tropes
Game design tropes that often apply to artificially intelligent characters in games, without directly concerning their behaviors:- Blending-In Stealth Gameplay: Requires that enemy AI reacts differently to inconspicuous and to suspicious player behaviors (as well as that there are "neutral" AIs to blend in with).
- Contractual Boss Immunity: When certain AI enemies are immune to insta-kill mechanics.
- Damager, Healer, Tank: This whole setup is predicated upon a specific implementation of enemy AI that allows players to arbitrarily Draw Aggro, making the AI act predictably and stupidly instead of being tactically effective.
- Drop-In-Drop-Out Multiplayer: If the game requires a minimum amount of players online, missing or leaving players can be substituted with AI bots.
- Escort Mission: A level design pattern based around protecting an AI-controlled character from harm.
- Gameplay Ally Immortality: When your AI companions are immune to death during regular gameplay.
- My Rules Are Not Your Rules: When the AI does not follow the same game rules as the players have to.
- Not Playing Fair With Resources: When AI opponents get resources for free to give them an advantage over human players.
- Player-Exclusive Mechanic: Not so much an AI trope, as one about what the AI cannot do.
- Player Versus Environment: A game mode where human players are pitted against the AI, instead of each other.
- Promoted to Playable: When a character previously exclusively controlled by the AI becomes playable by humans in the sequel.
- Reverse Escort Mission: A level design pattern based around a protector AI.
- Tabletop Game A.I.: Reactive non-digital AIs with even more emphasis on simplicity of algorithms.
- Video Game Delegation Penalty: When the human player can delegate menial tasks to the AI, but it's not nearly as good at it as the human.