Simulating Emotions Within Games

Gamasutra is running an opinion piece about the way video games handle simulated emotions. Most often, an non-player character's emotional state is used to either tell a story or to drive gameplay. The author suggests that as both concepts become more complex in modern games, the simulation of emotions must also become more dynamic to remain interesting. Quoting: "Most of our emotional simulations use a simple sensation/calculation/behavior loop. Someone says or does something to a character; this influences his emotional state; he acts upon his feelings. His emotional state then reverts to a more neutral state over time (I was angry half an hour ago, but I've calmed down now), or changes again in response to another sensation. If these systems are really simple they produce absurd results: a character is furious one moment and cheerful a second later, like a Warner Brothers cartoon character. This is the kind of thing you get with finite state machines. This approach doesn't take into account the fact that behavior itself changes emotions. Behavior is not merely an output to be exhibited; it also affects how we feel. It feeds back into our emotional state."

Comments

First Post!

[Anonymous Coward]

Emotional state - pleased and surprised.

Second Post!

[wild_quinine]

Emotional state - frustrated and disappointed.

Re:Second Post!

[albyrne5]

PHRASE ... "Emotional state" ... DOES NOT COMPUTE ...

Don't hurt the feelings of FSMs

[Schiphol]

The summary (and TFA as well) seem to be committed to the following two points:

1. Finite state machines will be unrealistically simple when simulating emotional responses.
2. Behavioural-feedback is a necessary condition for realistic emotional displays.

Point number 1 is unwarranted. Finite state machines may elaborate their input at an arbitrarily high level of complexity -finite may still be very large. Part of such an elaboration, of course, may be inner transitions between states that effectively amount to behavioural-feedback. There is nothing intrinsically un-dynamic to FSM.

Re:Don't hurt the feelings of FSMs

[Hoplite3]

I agree. There's no reason you can't have feedback in a finite state machine.

But the harder problem I think is properly displaying these emotions to the player, especially with subtle distinction. I've only seen one recent game (Mass Effect) that could occasionally use some small facial tics to give away emotional information. Changing dialogue would be very rewarding to the player, but difficult for the developer.

Re:Don't hurt the feelings of FSMs

[Yvanhoe]

Dwarf Fortress uses ASCII characters to display the actors and their various states. It is incredible how effective it is. IT is not about the graphical feedback, it is about the behavior : once you see someone moving erratically and throwing everything around, you know that something is wrong with him. When you see two ASCII character sleeping side by side in the same room, you suspect that something is going on. It is not about attitudes, but behaviors.

Re:Don't hurt the feelings of FSMs

[John Allsup]

Emotions are continuous in nature, and cannot truly be emulated with a device that is discrete in both space and time.

Re:Don't hurt the feelings of FSMs

[Creepy]

Dialog changes are fairly rare, and usually only in RPGs and Adventure Games for the exact reason you mention - they are a pain in the rear to program. One upcoming game that is supposed to have an "emotion engine" is Heavy Rain.

    I personally don't think an emotion engine is as important as emotionally attachable characters with appropriate dialog. For instance, the ancient game Below the Root is probably the earliest and best example of a game with characters that had emotional states, and in fact, some characters you could play could detect the state and know if that person meant good or ill and whether that person trusted you or not (or was afraid, etc). I was absolutely fascinated by that game in the mid 1980s - despite being aimed at children, it was entirely different than any game I'd played up until that time - largely non-violent, side scrolling, based on character interaction and puzzle solving, and had three very different protagonists (two were female, one male, which was unheard of). I think it's target market of children was wrong - I was a teen and spent more hours playing it than many other games I had.

I think it's more important how you feel about the characters in the game than how the characters feel about each other. Dogmeat is an endearing character from Fallout, despite often being reduced to a bloody pool more often than not (and forcing a reload! --- NOOOO - you stupid mutt). Other times, characters are added and designed specifically to elicit an emotional reaction, like (Pre-searing) Gwen in Guild Wars or the Little Sisters in Bioshock.

Re:Don't hurt the feelings of FSMs

[SatanicPuppy]

Fricking newage babble. Emotional states can be quantized as well as any other mental state. I'd normally say, "They just look that way" but they don't even appear continuous internally!

Emotional states change all day long, and it is perfectly cromulent to say "I was sad this morning, but I feel better now"

Re:Don't hurt the feelings of FSMs

[electricbern]

When you see two ASCII character sleeping side by side in the same room, you suspect that something is going on.

I suspect of ASCII pr0n.

Re:Don't hurt the feelings of FSMs

[FiloEleven]

Fricking newage babble. Emotional states can be quantized as well as any other mental state.

I am not sure what other mental states you are referencing, but I'm going to forge ahead anyway and claim that any quantization of an emotional state is simplistic, though it may prove useful to science and in communication.

I'd normally say, "They just look that way" but they don't even appear continuous internally!

Emotional states change all day long, and it is perfectly cromulent to say "I was sad this morning, but I feel better now"

Such a statement, although accurate to an extent, is overly broad. First of all, "continuous" is not the same as "static," so your remark that emotional states change all day long does not contradict the GP's point. Second, your use of the word "feel" is illustrative because it reflects the individual's current feelings (constantly referred to as his "emotional state" as if changing the name makes it more objective). It is important to note that if you ask someone how he is feeling, he is always able to provide an answer. This underscores the fact that feeling goes on all the time, every day, every conscious moment.

Every single thought that our focus rests on is accompanied by a fringe of perceptions, from the ambient noise of the room or surrounding area to how at ease one feels at this current location, along with a vast number of other emotional and environmental colorations that can be examined individually (by focusing on them) but never separated from the whole of perception. This is not some new-agey idea; it has been known almost since psychology's inception and certainly before 1900.

I believe strongly that the point in the article (as summarized by the original poster; you didn't expect me to READ it, did you?) stands:

Finite state machines will be unrealistically simple when simulating emotional responses.

It has also been known since before 1900 that our emotional response to things begins with physical symptoms, not with contemplation. We see the rampaging bear, our hearts skip a beat then go into overdrive, and we are afraid; not: we see the bear, decide to be afraid, then our hearts go into overdrive. Of course this can work in reverse at times, dwelling on a sad experience will lead to slumped posture and a downcast face, but every emotion stems from and results in physical changes. This fact leads me to believe that without a massive sensation-processing apparatus on the order of complexity of, say, a small mammal, a digital device will never be able to simulate feelings at a level that we would consider to be realistic. I further believe that we will never be able to artificially create consciousness in any way similar to our own without such an apparatus.

In closing, anyone interested in the creation of a consciousness owes it to himself to read up on the history of psychology in addition to all the standard AI information. A failure to understand the magnitude of the human being's conscious experience will lead only to continual frustration in the quest to create one artificially.

It's for *games*?

[Hognoxious]

It's for games? Yeah, I believe that.

"Hm, haven't seen him for 30 seconds..."

[M1rth]

What I find stupid is the fact that emotional states in games with any sneaking component revert way too quickly.

"Hey, I saw an intruder! Hey, he ran away and hid!"... 30 seconds later... "*whistling merrily on patrol back in 'no intruder' state*".

In many games, the enemy will walk right past a dead body, which is now an "object", over and over again.

Much more realistic would be, once you've been spotted once, for the "alert flag" in some radius (shout range, alarm range if they hit one, etc) to go to a default "middle alert" and simply stay there. It's your punishment for being seen, AND it'd be much more realistic. And it wouldn't, if implemented properly, require any more processing power either.

Re:"Hm, haven't seen him for 30 seconds..."

[TheThiefMaster]

Ah, the old realism vs. gameplay argument.

You should try playing some of the thief games, dead bodies provoke quite a reaction in that.

Re:"Hm, haven't seen him for 30 seconds..."

[Vario]

This would be easy to implement and some games show a similar behavior. Still this is not widespread because it just does not add to the gameplay.
A longer timeout for alertness would just mean, that you need to wait in a dark corner for a long time until the enemy finally goes back to "no alert". I certainly don't want to be punished for a tiny mistake by having to wait forever.
In a simulation rather than a game the enemy should not only react by increasing the alertness but calling for additional patrols, etc. which would reduce your chance of success significantly.

It is a fine balance between "not noticing a dead body" and "call for everybody to eliminate you".

Re:"Hm, haven't seen him for 30 seconds..."

[Creepy]

Thief? Heck, the sequel to the original stealth game, Beyond Castle Wolfenstein had this - part of the gameplay was dragging bodies out of sight so the guards wouldn't see them (the first game I believe had body spotting, but not dragging). If a guard spotted a corpse they'd immediately run for the level alarm and if that happened, you'd have SS all over.

The real issue is, for sake of gameplay, the finite state machine is usually reset or else you'd be hiding for hours or days of gametime, which isn't much fun, so games often reset the "normal" state much sooner than it would be in real life. Obviously in a stealth game there are serious issues if the AI never reverts to a "normal" state, as those games aren't designed for you to take on multiple attackers head on (Thief is a wonderful example of that), and constant reloads every time you're spotted isn't much fun either.

Re:"Hm, haven't seen him for 30 seconds..."

[argent]

This would be easy to implement and some games show a similar behavior. Still this is not widespread because it just does not add to the gameplay.

I suppose it depends on how much realism you expect from a game. And how much realism the game otherwise provides.

When the characters are abstract specters and you're a yellow ball, you expect them to behave crazily. When they're high resolution avatars with simple AIs, it makes it harder to keep those suspenders of disbelief on when they act brain-damaged.

Re:"Hm, haven't seen him for 30 seconds..."

[tepples]

When the characters are abstract specters and you're a yellow ball, you expect them to behave crazily. When they're high resolution avatars with simple AIs, it makes it harder to keep those suspenders of disbelief on when they act brain-damaged.

Which is why cartoonish art styles are still relevant in video games of the 2000s. When your NPCs' emotions are as shallow as they are in a game like The Sims or Animal Crossing, you want their appearance to match.

Re:"Hm, haven't seen him for 30 seconds..."

[Chabo]

From Yahtzee, on STALKER: Clear Sky

The mystical quicksave key is a dark and mysterious power that can change the very fabric of reality.

I was ambushed by a bunch of jerks on my way somewhere, killed one or two, hit behind a rock, and quicksaved. But then three of them all threw grenades and I ended up with a cloud of shrapnel instead of a face.

After I quickloaded though, they suddenly didn't seem to care. I was able to walk up and affably chat to them about how their day was going. One of them even offered to guide me through the forest, but halfway through he ran off, yelling "That's him! Take him down!"

I couldn't see anyone else around, but it seems he was talking to my processor because at that point the game crashed.

http://www.escapistmagazine.com/videos/view/zero-punctuation/271-S-T-A-L-K-E-R-Clear-Sky

Re:Don't hurt the feelings of FSMs...

[ciderVisor]

...praise their divine noodliness instead !

You think that's bad? :P

[Moraelin]

If you think that's bad, I humbly submit the following personal anecdotes:

1. Oblivion. So there's this mess of cultists and the high priest is right in front of them preparing to sacrifice someone. Being the sneaky barsteward I am, I plug him right in the head with an enchanted bow. So not only he does a spectacular back-flip in front of everyone, but he bursts into a very bright and spectacular flame too.

So the cultists freak out and start running around, don't find me. One minute later, they calm down and one of them goes, "It must have been the wind."

I don't know what kind of weather they have down there.

2. NOLF 2. So they had actually gone through the trouble of scripting reactions when an NPC finds a body. They'd shake it, ask stuff like "are you alive, comrade??", flip out and search for the killer, etc. Must have been fun in the original version.

Except some retard decided to replace all corpses with backpacks in the German version. You can probably see where this is going.

Yep. Some soldier would find a backpack on a bed in the barracks, freak out, and go "are you alive, comrade??" and the whole circus. To a backpack. WTF.

Re:You think that's bad? :P

[Creepy]

Oblivion and Fallout 3 have issues like that all over the place. It bugged the crap out of me when I walked into a necromancer lair wearing a necromancer robe and was still flagged as hostile by the cult lackeys - like they would know. Fallout 3 has the same sort of problem - if you're wearing gang armor you should not immediately be seen as hostile... I'd at least expect to get somewhat close before being identified as not an ally. And really, IMO humans should never be seen as a hostile faction to other humans unless there is some discerning factor (racism, wearing enemy armor, etc). How the heck to gangs recruit if they shoot everything that moves?

In both of these cases, other people thought the same thing and mods were released to address the problem.

Re:You think that's bad? :P

[tepples]

Yep. Some soldier would find a backpack on a bed in the barracks, freak out, and go "are you alive, comrade??" and the whole circus. To a backpack. WTF.

I think developers leave this in on purpose, as a thinly veiled protest against German BPjM classification.

Re:You think that's bad? :P

[Chabo]

Kinda like how in the German TF2, the body parts are gift-wrapped presents. :)

"Hey kids, blow up your friend with a pipe bomb, and you'll have a second Christmas!"

Re:You think that's bad? :P

[orkysoft]

Let me guess, there's no blood either?

It's the Ice-Truck Killer!

Re:You think that's bad? :P

[MadUndergrad]

Ooh, I just started watching Dexter. Very good show. HD really does it justice, too.

I don't see the problem

[Punto]

a character is furious one moment and cheerful a second later

So it's a woman? what's the big deal? actually, they seem to have the hardest part figured out already!

uh...

[PixetaledPikachu]

at first, I read that as "Simulating Emoticons Within Games". Why the heck would I want to simulate emoticons?

Re:uh...

[geminidomino]

I was even worse... "Stimulating Emoticons Within Games".

I thought it was about some sort of naughty easter-eggs or something...

Re:Fable1/2 tried

[geminidomino]

TIE Fighter?

During the mission debriefings, when you asked certain questions ("How many ships did we lose" or, if you failed, "Do you have any advice for me?") the officer would look pissed off, and other questions ("How many ships did we destroy?" and, if you got the bonus objectives, "What extra did I accomplish?") he'd get this smug little smirk...

Mass Effect

[jgtg32a]

just in case you didn't get it

Do you forget quantum physics?

[tepples]

Emotions are continuous in nature

What nature are you talking about? In the nature that I live in, everything is quantized. It just appears closer to continuous when averaged over trillions of particles.

and cannot truly be emulated with a device that is discrete in both space and time.

A sufficiently powerful digital computer could simulate everything down to the Heisenberg detail level, at which point the uncertainty of natural dithering becomes measurable. But all we need in a game is enough detail to fool the player.

Re:Do you forget quantum physics?

[spazdor]

Planck's Constant - the Nyquist frequency of spacetime?

Flowery Twats

[HTH NE1]

If these systems are really simple they produce absurd results: a character is furious one moment and cheerful a second later, like a Warner Brothers cartoon character.

Or Basil Fawlty?

Who cares what NPCs think?

[Reziac]

I certainly don't. NPCs annoy me, so I shoot them!!

simulated emotions!!!

[mcfatboy93]

:-(

Im smiling on the inside

Good enough for now

[Aoet_325]

Games do well enough for now at expressing emotion within the limits of graphics/voice acting/script

What I'd like to see are:

1. controls sensitive and natural enough that your character is able to clearly express how you are feeling with no effort on your part. If it's done well how your character moves and his expression will change without you even realizing it

2. NPCs that then respond to your emotional state at the time.

Just what an FPS needs

[Anonymous Coward]

Just what I need, bots that call out insults during my kills, and then follow with a tea-bagging and jumping on my "corpse" on the occasions that they manage to score a kill.

I think I prefered it when they only ran around in circles, unless the AI routine tells them where I am.