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Comment by jsheard | Hacker News Reader

For context: OpenAI is playing against a professional team this time, unlike the event a few weeks ago where the humans were skilled but not active pros or used to playing together.

This team isn't the strongest (they placed 17-18th during this TI) but OpenAI will play again tomorrow and the day after, presumably against progressively better teams.

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> his team isn't the strongest (they placed 17-18th during this TI)

Oh, is that all :P. Assuming a 2x buffer for players who are good but not competitive, there are maybe 200 humans in the world who are better at DotA. If mastery is 1 in 10,000, these people are masters.

No, there are way more than 200 players better than Pain, all due respect to them. That’s clear by looking at leaderboards. But team dynamics and synergy in this game matter so much that they are definitely in the top 20 of teams regardless of their individual skill.

Seeing OpenAI do so well against this team impressed the hell out of me.

A really big factor making up your ranking on the leaderboard is your ability to play in a chaotic game where your team and yourself aren't on the same page. Just taking the top players from the leaderboard (who aren't already on a top team) and putting them together makes up a team that is good enough to win against other similar random teams (hence their high rank) but can't win against actual teams, which is evidenced all the time in the open qualifers where actual teams that consist of lower ranked players beat them. TI open qualifer / regional qualifer / actual event placements are way better indicators on how good a team is than pub leaderboards.

The way TI is structured they invite one team from South America. So Pain is likely not in top 20, but still a very good team.

I know how TI is structured, but I’m confident they’re top 20 anyway. Which team not at TI is better, do you think? Complexity? Navi? I don’t think so.

Many believe that it’s an exponential curve so there’s a substantial difference between the first and twentieth place teams.

Even if this is true, pain is one of the unpredictable teams that can take a game off anyone. They went 3-1 against Liquid at the Birmingham Major.

Actually, "weaker" (top 20) teams regularly do take games off better teams so I don't think there's much evidence for an exponential skill increase between teams.

Looking historically at team ELO and how squads have gone on 27-series win streaks, this is probably right. Though I think the gap between "low-tier" TI teams and TI winners is getting much tighter. Group B at TI8 was so close the difference between upper-bracket and lower-bracket was 1 game for most of the teams.

*Elo, not ELO :)

lol, good catch. Gotta give Arpad his credit :)

Seems like playing one of the best 200 players in the world is a reasonable proxy for a top tier player.

I'm unfamiliar with DOTA rules, but does anyone know if there are any limitations on the openAI team? e.g. Things like keystrokes per minute, scroll speed, etc

Yes, as the sibling poster said, there is a 200ms reaction speed restriction on OpenAI. Also note that OpenAI is using the Dota 2 bot API (its input is not pixels, and its outputs are not mouse actions and keystrokes), so it has more precise information than the human team on things like unit coordinates and can target its actions more exactly.

This 200ms restriction seems really slow, but it isn’t. It feels extremely fast, to the point where some heroes and tactics used by humans are useless or impossible. For example, one of the humans played a hero called Axe. It was literally impossible to land one of his skills because it takes 400ms to use it. I’ve seen a lot of professional Dota but I’ve never seen Axe calls being dodged so perfectly and consistently.

If this game was balanced around AI rather than humans, this game would look very different.

200ms is a good measurement on how fast a skilled human can react with a single keypress like activating BKB or phase shift. Players like VP.Noone can be seen doing such reactionary moves even faster than 200ms. Double clicks will already take longer due to slow fingers, which would be the self eul's to avoid axe's call. The moves where eul's was used on axe or blink dagger to escape, well those require players to also move the mouse accurately, which takes even more time.

If OpenAI wishes to have human-like mechanical limitations to make things more about strategy, then they should definitely start adding some sort of action performing delays to actions based on roughly how long a skilled player would take to do them.

This made me think that on top of having a 200ms in actions perhaps the AI can use an action queue where each action will have a delay of 50 ms. This will be a good way to simulate the human latency in using fingers to send the keystrokes. So, if a the DP want to use eul, she will end up taking 200 (base latency) + 50 (first click) + 50 (2nd click) = 300 ms. Still would be able to dodge but now it is much more competitive.

The consistency is definitely a factor, but even in just the top 80th percentile it's quite common to happen.

These were the limitations for the previous OpenAI game:

- Random Draft using a pool of 18 heroes (Crystal Maiden, Death Prophet, Earthshaker, Gyrocopter, Lich, Lion, Necrophos, Queen of Pain, Razor, Riki, Shadow Fiend, Slark, Sniper, Sven, Tidehunter, Viper, or Witch Doctor)

- No summons/illusions

- 5 invulnerable couriers, no exploiting them by scouting or tanking

- No Scan

Not sure if this match has the same limitations, but all heroes in the current game but one (Axe) are in list above, so maybe they added a few new heroes to the allowed pool.

They didn't have the invincible carriers and had more heros this time around.

> had more heros this time around

They had a fixed draft from the above pool with 1 new hero:

Crystal Maiden, Death Prophet, Tidehunter, Gyrocopter and Lich

Lion, Necrophos, Sniper, Witch Doctor and Axe (the new one).

One thing to note is that there is a significant difference between five top-200 players and a team composed of the same, in terms of coordination and familiarity with playstyle.

During the last OpenAI showmatch the bots had an artificial 200ms reaction time imposed on them, I assume it's the same here but I'm not sure.

Thanks.

I don't believe this is the case, as OpenAI was able to hex (an immediate disable) Earthshaker before he got off Echoslam (a spell with no cast delay except the time to click the key).

The ES player didn't queue his abilities so there was delay between blinking and casting echo. Someone counted the frames and it was well over the 200ms minimum.

Here is a post from the Dota 2 subreddit discussing the timing with proof that OpenAI's reaction was over the 200ms minimum:

https://www.reddit.com/r/DotA2/comments/94vdpm/openai_hex_wa...

Yeah. I agree. It was over the 200ms minimum but it was artificial. No human could reasonably perform that type of action as relilably. And that has nothing to do with learning performance.

You can queue abilities to instantly cast them after the previous one finishes, so it is actually quite reasonable for a human to perform that type of action quite reliably.

They probably meant the reaction, not the blink and echoslam.

Did he blink in? Is there a delay there?

There's no delay, but when people looked at the replay, Earth Shaker was actually visible when he thought he wasn't. The AI that disabled him had precast his spell on the out of range Earth Shaker, so when Earth Shaker blinked in to range, the precast spell went off in the following server tick.

That's not what happened. The 200ms delay worked as intended. The reddit thread counting the frames can be seen here: https://www.reddit.com/r/DotA2/comments/94vdpm/openai_hex_wa...

That makes sense, thanks.

In general, the differences among a top echelon of human expertise are vastly smaller than those between humans and other kinds of agents, animals or AIs. We all share similar cognitive architecture for handling complex domains after all.

Once OpenAI Five defeat 3-4 pro teams convincingly, it could be presumed from the observation above that they will defeat any other top teams within a year at most, if sufficient resources are used for improving the AI. An exception is when a fundamental hidden weakness is found in the AI.

Another confounding factor is major rule changes where the game essentially becomes a different one.

> Once OpenAI Five defeat 3-4 pro teams convincingly, it could be presumed from the observation above that they will defeat any other top teams within a year at most, if sufficient resources are used for improving the AI. An exception is when a fundamental hidden weakness is found in the AI.

Not sure how you intended this, but the hero pool constraint is actually an enormous advantage for the AI. The current hero pool isn't, by any means, random. I don't know OpenAI selected it, but it's highly conducive to OpenAI Five's strengths--deathballing, mechanics, teamfight coordination, etc. It lacks essentially all of the heroes that humans would normally pick to counter that strategy.

Playing on an unrestricted hero set would test OpenAI Five in entirely different ways than playing on the current hero pool would. I would not be comfortable betting on your statement at all.

> I don't know OpenAI selected it, but it's highly conducive to OpenAI Five's strengths--deathballing, mechanics, teamfight coordination, etc. It lacks essentially all of the heroes that humans would normally pick to counter that strategy.

Isn't it the other way around - openai adjusted to the hero pool to come up with its' strategy, because it was trained on this hero pool.

If hero pool had only late-game melee carries - I assume openai would come up with a strategy that works with that.

I don't think so. It's quite easy to imagine that a computer would outperform humans in strategies that require precise execution and coordination in teamfights. In fact, it's not specific to OpenAI; even the built-in Dota bots' strengths are generally teamfight execution.

My guess is that if OpenAI 5 trained under a different hero pool, it would be weaker than it is now. It's very hard to predict how much weaker though.

> The current hero pool isn't, by any means, random.

Some of the restrictions they've discussed - like initially they couldn't handle with illusions, summons or invisibility at all. They obviously dropped the invis restriction.

My feeling is that the AI just learned that of the given pool, 'deathball' was the best (and specific heroes like Gyrocopter/Sniper were the most effective carries).

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