Artificial Intelligence

Artificial Intelligence (or A.I.) in the field of gaming and computer science, refers to the intelligence of the machines and the effort to re-create human-like intelligence in Non-Playable Characters (NPCs).

In Sword Art Online, the system is generally known for having a mixture of NPCs with very advanced A.I. and NPCs with very poor A.I.

«Top-Down AI»
In Sword Art Online, a Top-Down AI refers to artificial intelligence built from a program atop an existing computer architecture. Most NPCs in SAO have top-down AI, meaning they are scripted to state an exact certain thing in response to a very specific stimulus.

When speaking to Top-Down NPCs in a quest, a player must listen to the NPC through the entire duration of the speech. If not, the quest does not proceed, as the Top-Down AI is scripted in a very basic, simplistic fashion.

Top-Down AIs work from an Answer, and wait to respond to a question. Some AI can even be scripted and modeled to mimic human behavior, to almost be indistinguishable  f rom a human. These AI simply have more data to process, and have learned to mimic behavior, to fit a personality. Yui is a prime example of a very advanced Top-Down AI.

«Bottom-Up AI»
Bottom-Up AI are AI that work in the opposite manner of a Top-Down AI, where they compute an answer when a question is given, rather than having a preset answer to a desired question. Unlike Top-Down AI, who learn by the "Ask A, so answer with B" method (being from the top question, down answer), Bottom-Up AI learn through "Learn B, and answer when asked A". In other words, "true artificial intelligence," in the words of Kirito.

In the Sword Art Online Universe, the only known way to create a Bottom-Up AI is through the cloning of a human Fluctlight. A fluxtlight is the cloned brain of a newborn baby nurtured in VR.

List of known NPCs

 * Yui
 * Ruru - NPC on the 56th Floor who provides the secret of defeating the Floor Boss.
 * Underworld Residents