Witless enemies are an oft-cited failing of videogames, but while AI designers are forever finding ways to make more formidable opponents, is smarter always better?

Pandemonium breaks out. Alarm bells sound, red warning lights flash and guards come running to the scene of the crime. Meanwhile, you, the perpetrator, slink unnoticed into some shadowy crevice. Less than a minute later, peace has been restored. Guards return to their patrols – no more aware of you now than they were before you shot one of their colleagues in broad daylight. These guys are idiots. Of course, it is the very fact that they are such short-sighted, amnesiac goons, who don’t think to peer too closely into shadows or perform a systematic sweep of their surroundings that allows the player to overcome the tremendous odds stacked against them. It makes the game possible. It also makes it a game.

Such acts of idiocy are the articles of a familiar gaming language; an understanding that the game, no matter the realism of the setting, is a system of behaviors and mechanisms that can be understood, predicted and exploited. The stealth genre has long made use of guards who perform their duties with strict, inevitable fallibility, leaving openings for a nimble-footed spy, thief or assassin to slip past unnoticed. For all the grim texturing of Snake’s world, his opponents’ behavior conforms to a decidedly inhuman rule-set – it’s hard to think that real paramilitary goons would be so enraptured by the discovery of a gentleman’s magazine on the floor.

The strategy genre too is reliant on such foolish enemy decisions; the beauty of Advance Wars comes down to the fact that you can repeatedly exploit features of the AI – it will always pursue a cheap, unmanned vehicle with its full force, allowing you to create diversions and bore holes in its defense.

How appropriate an AI is for a game does not then run parallel to its absolute intelligence – but it’s not always simply because the AI may have some design mechanic to fulfill, such as exposing tactical flaws by chasing empty APCs.

“Designing an AI that takes optimal advantage of its knowledge about the game and maximizes its ability to solve problems results in AI that isn’t fun to play against,” says Epic Games’ Steve Polge, the man responsible for the Reaper Bot, a popular multiplayer AI made for Quake, and for much of the AI development on the Unreal Tournament series.

AIs may find it difficult to react in credibly human ways, may struggle with tactical complexity, but they tend to be a pretty decent shot if their skills aren’t tempered. And this has, for a long time, been the traditional approach: build a classical AI solution that maximizes some measurable objective – for example, collecting the most resources, finding the shortest distance to a goal, scoring the most points – and then either dumb it down or provide it with cheats to buff it up to the appropriate level.

The problem with this approach is that, if not carefully handled, it can lead to an asymmetry between the challenges facing the AI and the player that can feel unfair – a phenomenon that is well illustrated by the evolution of the racing genre. In the past, computer-controlled vehicles ran on conveyor belts – aware of the exact racing line, following it unflinchingly, never spinning off, never crashing – except when the player powered them off the track. But in order to make them possible for the player to defeat, AIs would slow excessively at corners, so that the player could inch past them in a slightly more powerful car.

moscallout“The closer a representation of a human is to reality, the slighter the flaws that can suddenly de-animate it”/moscalloutHowever, such simplistic hobbling of the AIs’ abilities is increasingly untenable, whether it is done to fit in with a design mechanic or in order to adjust the challenge; as games become more simulatory in their presentation, as these worlds become more and more credible, so too does it become easier for unrealistic AI behavior to upset the illusion.

In the words of David Hayward, of videogame consultancy Pixel-Lab, “The closer a representation of a human is to reality, the slighter the flaws that can suddenly de-animate it.” It’s the uncanny valley phenomenon, whereby the closer approximations of humanity become more unsettlingly inhuman than those resting in abstraction, and it applies to more than just the fidelity with which human bodies are rendered – if the context in which an AI exists is realistic, but its behavior conforms to abstracted ideas of gameplay, then the result can be jarring.