August 5th, 2018 was a noteworthy day in the history of mankind. It was a Sunday and had Europe aching in unusual heat and drought. But more important, it was the day when the machines gently asserted their dominance in the field of gaming. It was the day when our most skilled players lost a tournament of Dota 2 against a bunch of self-learned bots.
“Bot” used to be a vilification
How did we end up in this situation? Let’s look back at what “bot” used to mean in gaming. Twenty years ago, we were thrilled about games like Starcraft where you control plenty of aggressive, but otherwise dumb units in a battle against another player that also controls plenty of those units. The resulting brawls were bloody, chaotic and ultimately overwhelming with their number of necessary tasks (so-called micromanagement) and the amount of information that needed to be processed at once to react to the opponent. In a human versus human (or pvp for player versus player) game, those battles were usually constrained to a certain area and executed with a certain laissez-faire attitude. Only the best players could stage two or more geographically independent attacks and control every unit to their full potential. We admired those players like astronauts or rockstars.
If you could not play against another human, you would start a game against a bot. A bot usually had four things that worked in their advantage and a lot of things stacked agaist them. In their favor, they had minimal delay in their reactions, ultimate precision in their commands and full information about everything on the gamefield. And more often than not, they received more game resources and other invisible cheats because they didn’t stand a chance against even moderately skilled humans otherwise. Often, their game was defined by a fixed algorithm that couldn’t adapt to human strategy and situational specifics. A very simple war of attrition was enough to defeat them if their resource supply wasn’t unlimited. They didn’t learn from their experience and didn’t cooperate, not with other bots or allied humans. These early bots relied on numbers and reaction speed to overwhelm their human counterparts. They played against our natural biological restrictions because the programmers that taught them knew about these restrictions very well.
Barely tolerated fill-ins
Those bots were so dumb and one-dimensional that playing with them against other opponents was even more of a challenge because you always had to protect them from running in the most obvious traps. They weren’t allies, they were a liability that dictated a certain game style. Everybody preferred human allies even if they made mistakes and reacted slower.
The turning point
Then, a magical thing happened. An artificial intelligence had trained itself the rules of Go, a rather simple game with only two players taking turns on a rather static gamefield. This AI played Go against itself so excessively, it mastered the game on a level that even experts could not grasp easily. In the first half of the year 2017, the machines took the game Go out of our hands and continued to play against themselves. It got so bad that an AI that was named AlphaGo Zero taught itself Go from scratch in three days and outclassed the original bot that outclassed mankind. And it seemed to play more like a human than the other bots.
So we got from dumb bots that were inferior stand-ins for real humans to overly powerful bots that even make it seem as if humans are playing in just a few years.
The present days
It should be no surprise to you anymore that on that first Sunday of August 2018, a group of bots beat our best players in Dota 2. There are a few noteworty differences to the victories in Go:
- Dota 2 is a game where five players battle against five other players, not one versus one. It wasn’t one bot playing five characters, it was five bots cooperating with only in-game communication against humans cooperating with a speech side-channel.
- Go is an open map game. Bot opponents see every detail of the gamefield and have the same level of information. In Dota 2, your line of sight is actually pretty limited. The bots did not see the whole gamefield and needed to reconnoiter just like their human opponents.
- In Go, the gamefield is static if nobody changes it. In Dota 2, there a lots of units moving independently on the gamefield all the time. This fluidity of the scenario requires a lot of intuition from human players and bots alike.
- The rules of Go are simple, but the game turns out to be complex. The rules of Dota 2 are very complex, but the game refuses to be simple, because the possibilities to combine all the special cases are endless.
- Go is mostly about logic, while Dota 2 has an added timing aspect. Your perfect next move is only effective in a certain time window, after that, you should reconsider it.
Just a year after the machines took logic games from us (go and read about AlphaZero if you want to be depressed how fast they evolve), they have their foot in the real-time strategy sector, too. Within a few years, there is probably no computer game left without a machine player at the top of the ladder. Turns out the machines are better at leisure activities, too.
But there is a strange side-note to the story. The Go players reported that at first, the bots played like aliens. Later versions (the purely self-learned ones) had a more human-like style. In Dota 2, if you mix bots with humans in one team, the humans actually prefer the cooperation with the bots. It seems that bots could be the preferred opponent and teammate of the future. And then, it’s no longer a game of humans with a few bots as fill-in, but a game between machines, slowed down so that humans can participate and do their part – as a tolerated inferior fill-in.