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Adaptive AI in Games - Does it Really Work?
qasimodo asks: "I was recently reading a preview of Splinter Cell: Pandora Tomorrow, and then I came across this article at GameSpot saying Pandora Tomorrow will feature adaptive AI which 'will adjust itself to players' skill level'. I remember (and is also mentioned in the PT article) Max Payne also featured this, but I never noticed it. I guess that's the best way to know if it works, since it adapts to your gaming skills, but does it really work? Have you noticed it? Do you have proof of it?"
I remember reading an article about Gods by the Bitmap Brothers where they had helper triggers for people that had been stuck for a few minutes. They called it a shandyometer, after shandy drinkers obviously.
X-Com had a shandyometer, my old housemate used to send men who were very poor and irritating out, let them get slaughtered, then send in his main team and the game would have made it easier.
(For the non-Brits, Shandy's a mix of lager and lemonade (as in 7up/sprite), the old lore is that its drinkers are somehow unable to handle real beer)
Descent 3 always had adaptive AI. I remember when I first played it. I had played the prequels so I went into 3 with the same strategy I always had. It got me through quite a bit of the game, but it wasn't easy. Early in the game I was able to fly around really fast picking enemies off one at a time. As I played more they started to run away, regroup and attack in force. I countered that strategy by using bigger guns to destroy them. They then started to change formation to minimize the damage I could do to their whole group. While Descent 2 was the pinnacle of the series Descent 3 had revolutionary AI.
Also, I think that the sea battle AI in puzzle pirates could possibly be adaptive in some way. A couple updates ago they allowed brigands (computer controlled boats full of booty) to fire canonballs. Since then it has been widely agreed upon by players that they have increased in difficulty each and every day. There was an update last night, so we'll have to see what happened. I'm still a little unsure of this because if the AI was adaptive in some way, wouldn't they tell us?
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After reading that little snippet on gamespot, I've got the feeling that the game will be 'letting you win'. It states that if it takes you 20 tries to do something, the game will lower it's standards for you. Why did finishing Splinter Cell make me feel good? Because it makes me feel I've accomplished something. I've mastered the game, no matter how difficult the timing was, no matter how pixel-perfect I had to aim to kill that guy, no matter how hard it was to master. Unless they (Ubisoft) implement this Adaptive AI perfectly and unnoticeable (and I hope they will), I'm going to feel as if no matter how bad I play, or how crummy my timing is, I'm still going to master the game. Adaptive AI could really take the challenge out of any game.
What's the main reason players get disinterested in a game? Because they come across a level that they can't beat, and they get sick of the same ol' stuff over and over again.
If less people are buying these games, because they just aren't the master that you apparently are and would rather not get halfway through the game only to quit in frustration, it hurts the company so this move makes sense.
However, to satiate you, they should add an option to set the AI on the hardest possible skill level.
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as much attention as it is. After all, I believe it was NBA Jam which introduced this concept, though they called it "CPU Assist". Essentially, a player who was losing would get more and more help from the computer as his deficit grew and grew, making his shots much more likely to go in and letting him knock opposing players over much more easily. On the flip side, a player with a big lead would find most of his shots hitting iron, and his players would lose the ball and get knocked over if opposing players even looked at them.
I also recall reading many years ago in an issue of Sega Visions (Sega's failed answer to Nintendo Power) that the Jurassic Park game for the Genesis would have "Dynamic Play Adjustment". The only example I can recall of this is that if the player was doing well, gaps to jump would get wider. I'm sure there were other examples, but that's the only one I remember.
So, in other words, this ain't new.
This is the NFL, which stands for "Not For Long" if you keep making those bulls*** calls.
What that game really needed was a way to adapt to your attention span. When he would launch into one of those speeches about the rain on the pavement and how it made him feel, I wanted to shoot my Playstation.
The "adaptive AI" in Max Payne was simply a dynamic difficulty slider. I wouldn't be surprised if it was simply a matter of monitoring your kill rate, perhaps adjusted by your injury rate, and increasing enemy effectiveness (fire rate, accuracy, maybe damage multiplier if they really wanted to be devious) accordingly. I imagine the AI topped out fairly low, though, so the overall effect was negligible. I don't believe it was adaptive in the sense that it dynamically adjusted its battle tactics according to your battle tactics, as opposed to simple numerical effectiveness.
Say I tend to shootjump to the right when I head into battle. The AI couldn't care less. Now if it _did_ notice that enemies tended to die more often when I did so, and cause them to proactively fire where I would, statistically speaking, very likely end up, that'd be an AI to write home about.
The most remarkable AI in modern gaming that I've encountered of late is that of Virtua Fighter 4: Evolution (a bargain at $20 new, btw), in which battle profiles of players in the Japanese arcade circuits was distilled into what prove to be fairly different AIs. Dynamically speaking, the game tracks the areas that you tend to attack successfully (high, middle, or low), whether those attacks are strikes or throws, and whether you won or lost with those percentages...and, judging from its effectiveness at smushing me in the long run, adjusts its behavior accordingly. So while a given AI profile might tend to, say, try to counter middle throws often, that tendency might be further exaggerated as the bulk of my throws tend to come from that area.
Quite impressive not only for its dynamism but also for the wide and finely graded range of difficulty among the AIs. As you gain ranks in the Quest mode (from 1st kyu to 10th, 10th dan to 1st, and beyond), your opponents very slowly become more difficult such that you can actually observe effective tactics emerging and adjust your _own_ behavior accordingly. Quite a far cry from Street Fighter II, mm?
I can vouch for Max Payne's variable AI working. I played the game through once and thought "This is fantastic." So I decided to play the game through again. The first level was a breeze. I single shot to the headed every single enemy. Then, next level, all hell broke loose. The enemies were rolling, took at least four shots each, ducked bullets, hid behind things, shot back very accurately.. they couldn't kill me but I ran out of ammo quick. I never made it past the second level because the AI had jacked up to the highest level. If I recall correctly, when you die on a level it lowers the AI's abilities just in case it had them too high.
What they need to do is adjust to the players styles. I like to camp and snipe in just about every game. I wish it would then cause the AI to start moving more rapidly, and check sniper spots more often. Do you always do something when you enter a room? Then the AI should brilliantly counter it, so I have to get a new strategy. Do I always camp in the same place? Then nade me.
Second of all I dont want it to turn pathetically easy, even though every game should have a difficulty setting called baby or wuss. (especially racing games like Gran Turismo) that would let you win. I labored so many damn hours perfecting my skills to no reward in Gran Turismo Three and I want my Formula One cars NOW!!! But what is the fun if I never die and never get hurt and don't get that rush when you complete a challenge. Because when I beat GT3 I will be so happy and thrilled and I will feel my $50 and racing wheel paid off. I will buy GT4, hence a happy customer and money for the corporations giving a financial incentive to the suits.
What it should do is offer a hint, to really bad players(flash bang a room with possible enemies and friendlies!!). Adapt to my style. If I want to snipe, then those guards better give up the grenades and take up some binoculars and a rifle. If a player is good at one method, make the objectives possible using that strategy, but encourage all the others too! Adaptive AI should enhance game play and make the game last. If I completed the it the first time sniping, and I want to be forced to try close quarters combat next time, without setting something I have not done any harder and make me have to vary my strategies to complete it. If Splinter Cell pulls off what I want, then UbiSoft will be very rich and I will be one very happy gamer.
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Whether you intend for them to be tacticians, civilians, or just mindless grunts. on 'Easy' or 'Difficult' a bad guy should still know he should take cover, call for backup, etc.
I'd disagree:
A typical civilian is liable to run scared, shoot while running, empty their clip desperately, that kind of thing.
A regular soldier is liable to call for cover, move to a braced position or whatever for shooting, but still make some dumb mistakes.
A truly elite solider, the target is probably never going to know they and their squad were there until they are lying dead on the ground. They'll plan tactics in advance, have them well practiced and executed silently. They'll be better at scanning for targets, they'll be better at moving silently through the best areas of cover. When they do move, they'll be covered by an already well placed squadmate. Their communications will be as much via silent gestures as noisy radios.
Within that spectrum (and me not knowing much about elite forces), there's a huge range of variables for a given enemy. That security guard could be nothing more than a civilian in a uniform on easy difficulty yet an ex special forces soldier on high difficulty. They're still both "just a security guard" yet there's a huge range of differences in how their AI might act.
Ghost Recon has my all time favorite example of that. On the first mission, if you go around to the north of the valley, there's a slope that troops come down.
I'd played it once on easy. I managed to clear them all with just a single sniper and good reactions. As soon as they started getting shot, they just tried charging, firing wildly, hitting nothing.
On elite, the sniper died almost as soon as he gave away his position as half a dozen guys found cover, found him, lined their shots, then took him down.
Next I took a squad of three guys, including a light MG. I found some bushes near the bottom of the hill. I waited for them to come in to the open, then opened up. Quickly they dropped to the ground. Then they started moving in pairs back in to cover behind a boulder, the others providing supressing fire. As they kept the range between them and I, they were much harder to take down and I got maybe two of the six before they were safe. Now it became a case of do I have to clear them out or will they come after me? They answered that for me and came after me. Yet even then, they maintained great covering fire, from braced pairs who were taking advantage of the accuracy, moving from cover to cover.
In both cases, they were just about as accurate as before (they just used more accurate firing positions) and could take just as much damage (Ghost Recon is great for accurately handling how much mess a single bullet causes). It was entirely down to their use of tactics that they went from being a group of idiots to mop up to scarily hard adversaries.
Granted, those were skill settings, not an adaptive AI system. Still, that's what differing AI levels should be like. I can't stand games that differ difficulty by making shots do more or less damage, by simply upping numbers of enemies, by suddenly making enemies perfect shots while they still move in exactly the same way they always did.