How do you give artificial intelligence (AI) the illusion of thought? It’s a problem developers have spent years trying to solve. Notably, the Shadow of Mordor games’ nemesis system and Alien: Isolation’s xenomorph tricked players into believing NPCs had their own memories and independent behaviour.
White Paper Game’s The Occupation aims to take this even further. Not only are they extending it to multiple characters, but they’re also implementing it in a way that doesn’t rely on combat to express itself. It’s a game where your presence alone may set off a chain of events that change how an NPC behaves, and how you both might approach a situation further down the line.
The game is set in a fictional version of Manchester, England in the late 1980s. A recent terrorist attack has left 23 dead, leading to the creation of a new act that will threaten civil liberties, The Union Act (loosely inspired by The Patriot Act that was passed after 9/11).
While the developers may not explicitly claim a link between the game and current events—perhaps hoping to avoid controversy that comes along with it—it’s hard to ignore that behind this period approach are persistent themes, such as the conflict of interest between civil rights campaigners and security statism. This tension started coming to a head with the Prevention of Terrorism Act (1974-1989). That act pressured news organizations to surrender footage and information to the police. It also banned individuals from entering the United Kingdom, and allowed arrests without warrants.
In The Occupation, you play as a whistleblower reporter who has four hours to investigate the true nature of the bill—indicated by a wristwatch that you can pull up at any time. After passing through security, you’re left in a sandbox environment and it’s up to you where you go next. You can either go through the motions of your office job and hope to discover something by chance, actively search through offices for clues, or tease information out of sources in the hallways. However, not everyone will be forthcoming with the facts and you aren’t allowed to access some areas without arousing suspicion.
Talking to Pete Bottomley, co-founder of the Manchester-based studio and a designer on The Occupation, he elaborates on this idea, “The main inspiration was we wanted the open world and we wanted things to react to the player…where there are multiple approaches to the scenario. You may hear this one conversation happen and you might have a completely different experience to someone else, and they may never have heard that conversation.”
He adds, “I think that’s where the real-time aspect stemmed from. Just because we didn’t want pre-scripted setups. You know, you hit a little trigger and it just plays out this conversation. It just made sense that everyone had their own paths through the world, had their own jobs to do.”
White Paper Games implemented a few different tricks in order to make the AI work in the way they intended. For instance, the team placed “smart” objects throughout the different environments for the NPCs to gravitate towards and interact with. These include things like door handles, coffee machines, and cigarettes dispensers. This gives the AI the impression of lifelike thought by helping them to find their way realistically throughout the world, while grounding them in the game’s reality.
They also used Unreal’s built-in behaviour trees to let the AI know all the different options available to them.
“[Behaviour trees] are just a bunch of states that the NPC can switch through. They will just have a job state, walking around doing their job, and if the player is just sat down minding their own business they’ll just happily stay in that state. Whereas, maybe you go into a room and set off an alarm. All of a sudden, they will become alert and go to that spot in the world and maybe they’ll then be slightly more cautious and do a little bit of a search. Maybe they decide, ‘Oh, it’s nothing’ or maybe they decide that it was actually you if you’re in the area or something, and so they may stick close by you.”
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These go beyond normal “alert” states found in most stealth games, manifesting in both actions and their emotions. An NPC might try to hide evidence or contact other NPCs through messages telling them what they’re doing. This is intended to create a feeling of suspicion and intrigue, and can lead on to new narrative possibilities further down the line, as they deviate more from their working day.
There are also subtler ways for the player to get the AI to change their schedule. Bottomley says, “Everyone has internally simulated stats. It’s not stats that the player can see on the screen or anything like that, but if characters get stressed or they drink too much coffee, they’ll either go and have a cigarette or they’ll use the bathroom. That allows us to break the behaviour in a believable way as well. It’s like, ‘I have this job to do. It’s just lasted 45 minutes and I’ve drank three cups of coffee. Ah, I need to go and use the bathroom and break out of this.’ That may be a chance for the player to maybe get caught off guard a little bit. Maybe you want to follow them. Maybe you’re not sure what they’re doing, so that’s more—not random behaviour—but unscripted.”
The impact of this behaviour is that each playthrough will hopefully be different from the last. You’ll encounter NPCs in new areas, and doing different tasks, depending on your approach. The NPCs will then telegraph these new actions through memos and conversations with other AI. This allows you to schedule around their deviations and enter secret areas without their knowledge to find evidence about the act and interrogate sources, but can also lead to situations where you might be discovered by a security guard on their way to the restroom or a smoke break. So if you’re in an area beyond your security clearance, you’ll have to always be on your guard, and pay close attention to your surroundings to keep track of these behaviours.
The biggest problem with this type of approach to AI is that animations can suffer. The team didn’t just want the characters to have generic animations, but to inject personality into the way they moved.
“Animation and AI go hand in hand,” argues Bottomley. “That’s been the hardest thing to try and achieve, because obviously our last game didn’t have any of this kind of stuff. That’s been super difficult thing to try and get online and tackle.
“That’s why we stayed quiet for so long, because genuinely studios of our size don’t really try and achieve this type of fidelity in AI, I guess. Because we wanted every foot to hit the steps going up the stairs, we wanted every hand to hit the door handle going through a door. It’s kind of making sure everyone feels grounded and rooted in the world. Then just getting these emergent systems online, because it’s much easier to tell an AI to walk over here and do an action, but it’s much harder to make them aware of all their available actions and make informed decisions based on that.”
It’s easy to see why White Paper Games believes this was the right approach for telling its story. It demonstrates how difficult it can be to report on controversial topics and the extent governments will go to mislead and coerce, as well as hammering home how the slightest of opportunities can lead to major breakthroughs or new information. Being a journalist in the UK and the US is becoming increasingly difficult, with the rise of more “security-minded” governments. There’s often resistance to investigative work from those in power. Dead ends. Suspicion. Unpredictability. Deadlines. Their AI system, and the concerns and frustrations it communicates to players, brings these issues to the foreground and asks the player to confront them, or fail trying.