Gamasutra: The Art & Business of Making Gamesspacer
View All     RSS
October 24, 2014
arrowPress Releases
October 24, 2014
PR Newswire
View All
View All     Submit Event

If you enjoy reading this site, you might also want to check out these UBM Tech sites:

Mind Games: Offloading Cycles to the Player’s IPU (Imagination Processing Unit)
by Ben Serviss on 07/16/13 09:10:00 am   Expert Blogs   Featured Blogs

The following blog post, unless otherwise noted, was written by a member of Gamasutra’s community.
The thoughts and opinions expressed are those of the writer and not Gamasutra or its parent company.


This article originally appeared on

The Sims
What's happening in this screenshot from The Sims 2? It's up to your own interpretation. (Screenshot: IGN)

At first glance, computers and video games seem to be a perfect match. Computers allow games to have absurdly complex rule sets that nobody has to remember, they can create real-time simulations that would be impossible to do otherwise, and they allow us to play with other people all over the world.

 Yet in some ways, computers are terrible for video games.Yet in some ways, computers are terrible for video games. In a Q&A at Game Horizons a few months back, Will Wright remarked on certain tasks that the computer is ill-suited for, citing Maxis’s decision to have the characters in The Sims speak in the gobbledygook Simlish language instead of English.

“For example, in The Sims, when you hear the people talk, you don’t actually hear them saying anything. You hear this kind of gibberish language. Through a lot of experiments, we determined that we could actually have them speaking in English or some other known language, but they very quickly became robotic and repetitive. On the other hand, if they speak gibberish, your mind naturally fills in the blanks and imagines a conversation… In essence, what we did is we offloaded that part of the simulation into the human imagination.” –Will Wright

Recently, Bioshock Infinite designer Tynan Sylvester elaborated on this concept of offloading elements of a computer game simulation into the player’s imagination in a masterful Gamasutra blog post. And while the idea is certainly compelling and the Sims example rings true, finding concrete ways to incorporate the main concept into games in development can be baffling. But by digging deep into the core problem, we can discover valuable ways to use the concept to strengthen our designs.

And all of these ways rely on maximizing the player’s IPU – or Imagination Processing Unit.

The IPU is the Gateway to Immersion

It’s the same reason the book is often better than the movie. With reading, the experience is a collaboration between the reader and the author. The author assigns specific things for the reader to simulate in their IPU, and the reader complies, helping craft a personalized experience that the reader can easily buy into.

Whereas with films, the entire screening time is a didactic experience of the filmmakers explicitly showing viewers what they want them to see. Sure, cinematic masters may infuse their movies with sublime beauty and intriguing scenes open to interpretation, but as a medium there is much less room to have a highly personalized experience.

Games, on the other hand, can be both. Game designers and creators lay out the world and the immutable plot points/mechanics, and then players are granted the freedom to live the moment-to-moment experience between those points. The degree of flexibility varies from game to game, but the virtue of having any kind of freedom is what makes games so special.

Using the IPU

The ideal solution here, if you’re intent on following Wright’s example, is to have the player fill in as much of their flexible in-between-predefined-points time with their own imagined meanings and implications.

While each game will call for different solutions, here are a few examples that have worked well in the past:

The Walking Dead
The Walking Dead's simple "they will remember that" system engages the player's imagination on a subtle level.

To start, look to content-heavy areas or gameplay sections that follow a formula as opportunities to offload to the IPU. In the case of The Sims, character dialog would have required reams of text written and localized for each territory the game was released in. By opting for the Simlish solution, all of this work was rendered unnecessary, saving hundreds of hours of development (at least).

In the case of Telltale's The Walking Dead, having conversations with characters is a solid pillar of the game’s design, and so it follows that conversations are a largely formulaic part of the game. By adding a simple “[Character] will remember that” message at the end of every conversation, players internalized the idea that each character they spoke to would bring all of their previous conversations and baggage with them throughout the game, even if a character only had one dialog scene before meeting an early death. Doing this made each character feel more real, since you could easily imagine them carrying their life experiences with them into future dialogs – just like real people do.

Use text to give brief insights into other characters’ mindsets outside of dialog. It’s mystifying why this isn’t used more. Classic games Carmageddon 2 and Operation: Inner Space both utilized this to great success. In both games, you compete in open-ended levels with multiple ways to achieve victory. In both games, you competed against crudely-rendered opponents, but one simple addition made them seem more alive than in any comparable current-gen game: brief text descriptions telling you what they were thinking.

When you shot at a neutral spaceship in Operation: Inner Space, you would see their description change from “Aimlessly wandering” to “Seething with fury” – and the payoff from this simple addition was immeasurable. Sharing their hypothetical ‘inner thoughts’ made an enormous difference in helping players visualize them inside their vehicles, making confrontations infinitely more exciting. Enemy ships and cars became fully-realized entities, making collections of AI routines and scripted behaviors seem like real enemies out for your blood.

Carmageddon 2
Fighting an AI opponent who is explicitly "Totally pissed off" makes quite a difference. (Carmageddon 2 screenshot: Neoseeker)

Use character dynamism to prompt questions. In other words, have characters do unexpected things that make total sense, given the context. In Hotline Miami’s first level, after brutally slaying your first group of foes, your character unexpectedly drops to his knees and vomits in an alley. Was it the shock of killing a bunch of dudes? Was he on drugs? It’s never really explained, but this disquieting question prompts unanswered suspicions in the player’s mind that never really go away, which perfectly complements the game’s deranged atmosphere.

In Bioshock Infinite, when you explore Battleship Bay with Elizabeth after rescuing her, she marvels at all of the sights, trying to experience everything at once with several custom animation sequences. In the context of the game, this makes total sense – she’s a young woman who’s never been outside of her solitary tower, and naturally would want to poke her nose into anything that hinted of new. The small touches in this scene help endear her to the player, reinforcing both her curiosity of the outside world and her sad life up to this point as a captive.

Practice brevity in world-building. For most players, quality trumps quantity. Dishonored may have had a traditional linear story, but the world building was very well done. Throughout the game you would stumble upon short snippets of text – diary entries, poems, descriptions of far-off places – that helped the player paint a picture of Dunwall as one of many grim places in an equally grim world. The short messages scrawled in Left 4 Dead’s safe rooms are widely accepted as a prime example of efficient world-building, imparting lots of meaningful incidental information without the intrusion of a cutscene.

On the other hand, Bioshock Infinite gorged itself on this kind of world-building to excess. The game had plenty of incidental props and displays, but they were absolutely EVERYWHERE. At times, it felt less like a game and more like a walking tour of extravagant billboards and set pieces, diluting the player’s ability to discover elements of the world themselves. In this example, the designers had taken on simulation duties of the in-between moments for themselves, depriving the player of making these connections.

(If) Optimize the IPU, (Then) Create a Rabid Fanbase

While it’s a lower priority than refining core mechanics and working around technical limitations, giving thought to maximizing use of the IPU can have surprising dividends for the end user experience, not to mention saving development time and resources allocated to less effective systems and content.

If anything else, getting used to the concept of the IPU as a legitimate development resource can have enormous implications in creating games that play, react, and feel more meaningful than ever.

Ben Serviss is a freelance game designer working in commercial, social, educational and indie games. Follow him on Twitter at @benserviss.

Related Jobs

Digital Extremes
Digital Extremes — LONDON, Ontario, Canada

University of Central Florida, School of Visual Arts and Design
University of Central Florida, School of Visual Arts and Design — Orlando, Florida, United States

Assistant Professor in Digital Media (Game Design)
The College of New Jersey
The College of New Jersey — Ewing, New Jersey, United States

Assistant Professor - Interactive Multi Media - Tenure Track
Bohemia Interactive Simulations
Bohemia Interactive Simulations — Prague, Czech Republic

Game Designer


Christian Nutt
profile image
Two thoughts:

I think The Walking Dead's really overvalued by people -- but I think this is part of why. I don't think it really does any simulation of character personalities with any level of nuance, and its choices are often quite false. But the game does a lot of fooling (and I don't say that pejoratively, because I don't think it was done maliciously) into thinking that a lot more is going on there than actually IS going on there.

Secondly, I feel like games that are filled with tomes of lore on bookshelves etc are really actually quite lazy. Sure, some of the audience may love this, but in any other storytelling medium this would be background information that the creators know but which is never fronted to the audience, and all communication would have to make sense on its own without this stuff.

Tomb Raider is particularly egregious about this. The story doesn't make much sense unless you listen to the audio logs, but it's not even a complicated story and there's very little excuse for it. And if you do listen to the logs, it's insanely predictable, too, so double-fail. Dreadful.

Ben Serviss
profile image
I concur- over-reliance on supplementary materials can make the main experience feel diluted.

When audio logs were introduced in System Shock 2 (the first use of them, as far as I know), they were an innovative way to convey story information in a way that made sense for the game without costly cutscenes. In Bioshock and especially Infinite, they make less and less sense. Why would the leader of a rebellious faction leave her recorded private thoughts just lying around?

There are bound to be better ways to convey story than relying on what worked in the past. Involving the player's input and imagination as much as possible is a great way to stay focused on what really matters.

Adrian Hall
profile image
I agree completely with point 2. Still, I do encounter many people who equate "good story" with "lots of consistent lore". I think there is a large enough audience to support that approach, even if I personally find it incomprehensible.

Ian Uniacke
profile image
@Christian: I think it's more akin to Tolkien's appendices. It gives you more information if you are interested. I could be misreading but maybe you are more concerned with bad use of supplementary material? The sub plot in system shock 2's dialogues was amazing and actually added to the main story, but you could still enjoy the game without them. The same is true for Metroid Prime. It sounds like (but I haven't played it) Tomb Raider is just using these as a lazy way to fill in plot holes.

I totally agree about your first point though.

Georg Fischer
profile image
"When audio logs were introduced in System Shock 2 (the first use of them, as far as I know)"

Not quite correct. They were in the CD version of System Shock (1).

(Technically in the floppy disk version too, but you could only read them, not listen to actual audio files.)

Ben Serviss
profile image
Thanks for the info! Had a feeling I put that disclaimer in for a reason )

Sam Derboo
profile image
Alone in the Dark had them even before. They were written logs in the context of the story, but the CD version would still read them to you, and they had the same narrative function as in System Shock.

I have to disagree about The Walking Dead's 'character x will remember that' line. It was one of the things that massively disturbed the experience for me (alongside the horribly staged action scenes and the game getting some of my minor choices confused even within the first chapter). It didn't feel like having made a choice of actual impact, it felt like an achievement unlock.

Vinicius Couto
profile image
Great article. I've read about using players imagination to fill in some gaps (specially in horror games), but it's good to see some more analysis and examples on the subject.
Speaking of examples, I'd like to add two more, concerning storytelling:
1. Dark Souls. The whole lore is only implicit presented to the player through item descriptions, some dialogs and level cues (where you find certain item might be important, for example). It's the player that must fill in the gap between all that, and I think player's imagination makes the world much more interesting and expansive than the developers could.

2. Blendo's Thirty Flights of Loving. It's story is told through short scenes, not necessarily chronologically, that the player must interpret to get some sense of what's going on.

Luis Guimaraes
profile image
It's impressive (or maybe not) that negative space is so underused and underrated at this day an age. But then we're transitioning between the "realistic graphics are what make games good" to the "voice-acting is what makes games good" era now, so things won't evolve for a long while.

Michael Joseph
profile image
The Sims gibber jabber could just as well have been replaced with nothing leaving just the hovering emoticons.

So this article is saying beyond the everyday decisions on WHAT to abstract away in a game's design, designers can do an even better job if they're also thinking in terms of HOW to abstract away various game elements... or how to not implement something (turning non action into action).

Sim talk is an example of good old fashioned game polish.

It seems this article presents perhaps a rule of thumb... if you can't implement it well in a non abstract way, implement it well in an abstract way.

Adrian Hall
profile image
I have been thinking along much the same lines recently. Designers have always depended on players to create meaning from abstractions (look at any Atari 2600 game), and I think that much of the past decade has been spent trying to break out of that pattern...not necessarily with good reason.

What really makes the Walking Dead example work so well is that humans NECESSARILY train themselves to infer information about the behavior of others. I can only ever see what my brother does, I can never see inside his mind, so my brain has developed advanced systems for guessing what he might be thinking without ever having received concrete information about it. This means that Telltale can write characters who behave consistently and act like real people, then let the player's brain do the rest.

On my last Ludum Dare game I had several people convinced that I had developed dialog trees and modified the ending based on what the player had done in-game. In reality, all I did was write dialog that made specific references to things that the player may or may not know about, but felt natural no matter what the player had done before. Players filled in the gaps with intent on behalf of NPCs.

We think more interesting things every day than we will ever dare to write or say.