Will Wright says the original Sims AI was actually too good: ‘Almost anything the player did was worse than the Sims running on autopilot’

As part of the 25th anniversary of The Sims, the New York Times spoke to the original game’s lead designer Will Wright, who gave some insight into how its AI was programmed. Part of the inspiration came from an unlikely source: his house burning down in 1991.

It was nothing like the fires in The Sims, which are usually caused by someone with a low cooking skill being anywhere near a toaster. Wright’s house was caught in the Oakland Hills firestorm. “When I returned to the ashes of my house, I noticed that the only things still alive were ants,” Wright said. “They had burrowed deep into the ground to survive the fire and were living off the dead carcasses of what they could forage.”

Rebuilding his life, and having to reacquire so many of his basic possessions, fed into the idea for The Sims. But so did his observations of ants, which he’d been paying attention to as SimAnt was a year into development at the time. When it came time to program Sims, they were given a similar AI to SimAnts, only where the ants prioritized activities based on pheromone markers in their environments, the Sims cared about objects. The fridge broadcasts its ability to reduce hunger, the bed broadcasts its ability to reduce tiredness, and so on.

The problem was, Sims were too smart about prioritizing their needs. “In early versions of the game, the autonomy was too good,” Wright said. “Almost anything the player did was worse than the Sims running on autopilot.”

Maxis had to dial it back, and instead let each Sim choose randomly from a selection of their top priorities. Which is how we ended up with a game where Sims wet themselves instead of going to the toilet, make themselves a bowl of cereal instead of cleaning up, and wander off to do something else before they’ve even eaten the cereal.

The sequels dialed this overcorrection back a little, making it possible to sit back and watch your Sims go about their lives without disaster. Having been trained on the original, I can’t help but micromanage my Sims still, even though I don’t always need to. What if they burn the house down and there’s nothing left but ants?