AI Understands Monopoly Value

[Catt]

I came across something interesting yesterday in my current game. I don't recall seeing this before, and also don't recall seeing a post or thread on the subject.

It seems that in my current game an AI civ understands that it controls a monopoly of one of the available luxuries, and seeks to charge a monopolist's price for the luxury. The civ in question is Russia. Catherine controls several Spices and all the Incense on the map. One other civ controls several Spices. In other words, the "Spice-less" of the world may trade with two different potential suppliers, while the "Incense-less" of the world must go to Catherine. The price differential is not huge, but it is evident, and seems to contradict in a small way the well-known and widely-believed "fact" that AI civ's value luxuries only on the basis of the number of happy faces they will produce in the buyer's empire.

Below is a screen shot showing Catherine ready to accept a supply of Silks and 8 gpt for a supply of her Spices (I have obscured the minimap because I may share this game beginning with others, and don't want to spoil the game).

[Catt]

Monopoly Value - Part 2

Below is a screen shot showing Catherine unwilling to accept a supply of Silks and 9 gpt for a supply of her Incense. Both shots taken from the same turn, without any intervening changes (without ever leaving the diplo screen).

[Ethelred]

Interesting. I think someone mentioned this possibility recently but it was in passing and no evidence was presented.

Thank you.

[Theseus]

Interesting... one would think there would also be a modifier for the number of resources Russia has, in which case spices would be more expensive. That's obviously not the case.

Cathy should charge more!!

[alexman]

Good job, as usual, Catt!

I agree with Theseus. The value of the monopoly should be greater than what it appears to be.

In any case, monopolies are something to aim for. In addition to not having the AI trade with each other instead of with the human, the human can charge more for his own monopoly resources.

[Catt]

I didn't figure out to the gold piece what the difference was, but I could go down to 7 gpt and add 10 or 12 gold as a lump sum for the Spices and could add some number of gold as a lump to get her to accept 9 gpt for the Incense -- as you both have noted, not a big difference.

BUT - assuming Cathy survives, it will be interesting to see the price differential when hospitals (and larger cities) come into being. Also, it would be interesting to see the price differential if, say, 3 or 4 different civs had Spices -- i.e., plenty of suppliers in an efficient marketplace. My gut tells me that there is an algorithm that works something like the tech devaluation algorithm -> an equation involving number of suppliers, number of potential buyers, value in happy faces, etc.

Catt

[bongo]

Thats interesting. In my current game there are two suppliers of incense, myself and the french. If I conquer their city the rest of the world will have to buy incense from me only. Which mean I can charge more

Life is good!

[Alex]

This thread proves that we need a comprehensive and detailed commerce screen, not that almost useless screen that we have now.

[DeepO]

well, I've seen it before as well, but I'm unsure what is causing it. I think there are more factors at work, of which monopoly certainly is one. Other things might include how much is available of a certain luxury, how bad the other party needs it (I've seen quite a few times that the 8th lux is a lot more expensive than the 3rd or 4th.), and amount of happy faces or size of the recipient. Sometimes you see a price difference between luxuries even if there is no monopoly.

BTW, the same sometimes happens with resources: in my last game the Indians wanted to pay more for saltpeter then for rubber (oil was available, but no tanks yet, so saltpeter wasn't totally useless). I was the only one with an excess saltpeter, while rubber could be bought from multiple civs...

DeepO

[Arrian]

I have noticed an AI placing a higher value on one of its luxuries over another, but for some reason I didn't really think about it.

-Arrian

[Skeeve]

Nice analysis.
It makes sense to me that the algorithm dealing with resource value may include a modifier for a monopoly (or oligopoly).

In any case, from a miltary standpoint, the AI is programmed to recognize the value of resources (as is evidenced by bombers and battleships destroying improvements on them), so it would make sense that the AI would be programmed to take advantage of them peacefully (economically).

On the other hand, the AI sometimes spends a lot of time bombing (or pillaging) improvements on useless resources (like saltpeter after tanks are around).

[vmxa1]

It seems to me that the price they want is a function of how much you have. If you have lots of cash they will ask for large sums. It hardly ever seems to be a relationship with it true value.

[Catt]

Originally posted by DeepO
Other things might include how much is available of a certain luxury, how bad the other party needs it (I've seen quite a few times that the 8th lux is a lot more expensive than the 3rd or 4th.), and amount of happy faces or size of the recipient.

I have always operated on the belief that the value of a luxury to any given civ was directly related to the number fo happy faces it produces. To civ A, the luxury might be luxury number 8 in a sprawling, well-developed empire with numerous size 12+ metropolises. In that case the luxury will generate 4 happy faces in every metropolis that has a marketplace. However, the same luxury is worth a heck of a lot less to a 3 city civ that only has one existing luxury -- it will produce exactly 3 happy faces. This pricing methodology is why we so often see complaints from posters that %^**&^ wants furs, wines, gems, spices, my world map, combustion, and 425 gold all for one lousy supply of silks (i.e., the human player is way ahead of %^**&^ and the supply of silks will generate a ton of happiness for the human while the return value of the multiple luxuries doesn't even compare).

Sometimes you see a price difference between luxuries even if there is no monopoly.

I don't doubt it - but I'd just never seen it before. I have definitely seen a price difference for the same luxury from different civs, but had never seen a price difference for different luxuries from the same civ.

BTW, the same sometimes happens with resources: in my last game the Indians wanted to pay more for saltpeter then for rubber (oil was available, but no tanks yet, so saltpeter wasn't totally useless). I was the only one with an excess saltpeter, while rubber could be bought from multiple civs...

I don't have a good sense of how the AI values strategic resources. My best guess is it has something to do with availability, and with the productive power of the buyer civ. I played a recent OCC game in which a scarce oil resource cost me 10 - 15 gpt during the age of tanks, planes, and battleships, IIRC. But how many tanks can an OCC civ make in 20 turns? In a "normal" game with a lot of cities that can produce a lot of advanced units in 20 turns, I can't ever recall getting a deal on oil that was even close to 10 -15 gpt.

But the real difference is in the discussion between strategic and luxury resources. Strategic resources enable certain units and even certain improvements -- the value of the units obviously varies over the course of the game. But luxury resources are luxury resources - they all produce happy faces, and one's citizens do not care if one chooses to import furs, wines, gems, etc. - they just want the happy faces.

So, I honestly have no idea if there is a monopoly or "scarcity" factor coded into luxury resource valuation, but I was surprised to see pricing variations on different luxuries from the same civ -- if the only pricing methodology was happy faces in buyer civ, one luxury should always be equally valuable as the other luxury.

Originally posted by vmxa1
It seems to me that the price they want is a function of how much you have. If you have lots of cash they will ask for large sums. It hardly ever seems to be a relationship with it true value.

In one of the chats Soren indicated that this was coincidence and that the AI does not price based upon the human buyer's ability to pay.

Catt

[alexman]

Originally posted by Catt
I don't have a good sense of how the AI values strategic resources. My best guess is it has something to do with availability, and with the productive power of the buyer civ.

I believe it also depends on what the buyer can do with the strategic resource. For example, you can buy oil (available with Refining) dirt cheap before you discover Motorized Transportation (which allows you to use the oil for tanks).

[Catt]

Originally posted by alexman


I believe it also depends on what the buyer can do with the strategic resource. For example, you can buy oil (available with Refining) dirt cheap before you discover Motorized Transportation (which allows you to use the oil for tanks).

Yup - exactly. What will the oil allow me to produce?

If I haven't discovered Combustion, then nothing! If I've gotten all the way into the modern age but only have 1 or 2 cities, not much! If I'm one of the 3 or 4 leading civs with a decent and well-developed empire, then my lack of oil is a critical handicap, and its availability would allow me to crank out an awful lot of powerful units quickly. If I'm the biggest, baddest, meanest civ around . . . well, I might just take that oil rather than buy it