Researchers at Portugal's Universidade de Lisboa and North Carolina State University have developed a tool and a mod that makes NPC interactions in The Elder Scrolls 5: Skyrim a little more like those in The Sims, with the overall goal of varying NPC behavior for a richer player experience.

The tool is called CIF-CK, built on the Comme il-Faut AI model developed in 2012. It's implemented in "Social Skyrim," which is part of the master's thesis of Manuel Guimarães, a student at Lisbon.

The mod creates greater variability in NPC interactions by allowing them to act on their changing opinions of other NPCs, which are shaped by their interactions with the rest of the NPCs and the player. The original CIF architecture would keep track of NPCs' feelings but didn't turn those feelings into action.

In “Social Skyrim,” CIF-CK does. According to the mod’s description on SteamWorks:

NPCs ... use social interactions (quests) such as flirting, complimenting, insulting, embarrassing (etc) to interact with each other. They try pursue romantic partners and insult those who they feel disgusted by. They try to make friends and introduce themselves to those that do not know them. The best part is that YOU can insult them too! Or flirt with them, or ask them to marry you, you choose! Manipulate them, destroy their relationships or help them build one, or just wait and see what the end result will be without interfering.

Another key distinction: Every agent under CIF was aware of all of the other agents. CIF-CK leaves that knowledge up to the developer’s choice, so that NPCs only know what the developer wants them to know.

“Most games now rely on scripts to govern NPC behavior,” said Arnav Jhala, an associate professor of computer science at N.C. State. “In other words, there are decision trees that dictate an NPC’s response to whatever the player is doing. That’s fairly limiting, and means that any two players that make the same decisions will have the same interactions with NPCs.

"We want to move beyond that, to a more immersive gaming experience," Jhala said. "And Skyrim was the game we started with.”

Guimarães, Jhala and Pedro A. Santos (also of Lisbon) have authored a paper about their work, which will be presented Aug. 22 at the IEEE Conference on Computational Intelligence and Games in New York. Jhala hopes that the demonstration offered by Guimarães' mod catches the attention of developers and brings this capability to more games.

"This work demonstrates that tools like CIF-CK can be implemented on a large scale,” Jhala says. “We’re now hoping to work with gaming companies and game developers to incorporate the CIF-CK approach into their development processes — or at least get inspired by it."

"Social Skyrim" is available through both Steam Workshop and NexusMods for installing and using it are on those pages.