badger

Karma: 2,488

badger Apr 3, 2014, 5:13 PM
3 points
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in reply to: CronoDAS’s comment on: [Error communicating with LW2 server]
Exactly. No need to put tunnels underground when it makes substantially more sense to build platforms over existing roads. This also means cities can expand or rezone more flexibly since you can just build standard roads like now and then add bridges or full platforms when pedestrians enter the mix. Rain, snow, and deer don’t require more than a simple aluminum structure.

badger Apr 1, 2014, 11:03 PM
0 points
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in reply to: Slackson’s comment on: Open Thread March 31 - April 7 2014
What do you mean by applying Kelly to the LMSR?

Since relying on Kelly is equivalent to maximizing log utility of wealth, I’d initially guess there is some equivalence between a group of risk-neutral agents trading via the LMSR and a group of Kelly agents with equal wealth trading directly. I haven’t seen anything around in the literature though.

“Learning Performance of Prediction Markets with Kelly Bettors” looks at the performance of double auction markets with Kelly agents, but doesn’t make any reference to Hanson even though I know Pennock is aware of the LMSR.

“The Parimutuel Kelly Probability Scoring Rule” might point to some connection.

badger Apr 1, 2014, 12:36 PM
5 points
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in reply to: ahbwramc’s comment on: Open Thread March 31 - April 7 2014
Hidden Order by David Friedman is a popular book, but is semi-technical enough that it could serve as a textbook for an intro microeconomics course.

badger Mar 13, 2014, 5:09 PM
2 points
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in reply to: RomeoStevens’s comment on: Irrationality Game III
What are a few more structured approaches that could substantially improve matters? Some improvements can definitely be made, but I disagree that outcomes are much worse. Two studies suggest marriage markets are about 20% off the optimal match (Suen and Li (1999), “A direct test of the efficient marriage market hypothesis”, based on Hong Kong data, and Cao et al (2010), “Optimizing the marriage market”, based on Swiss data). While 20% is not trivial, it’s not a major failure.

If there are major improvements to be had, I expect it to come through individual attitudes and expectations, not overall structure. Does advice like “don’t become fixated on one person while you’re still young” count as more structure?

badger Feb 26, 2014, 9:43 PM
7 points
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in reply to: Scott Garrabrant’s comment on: Open Thread February 25 - March 3
Scarce signals do increase willingness to go on dates, based on a field experiment of online dating in South Korea.

badger Feb 26, 2014, 2:20 AM
2 points
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in reply to: VincentYu’s comment on: Open Thread February 25 - March 3
Thanks for the SA paper!

The parameter space is only two dimensional here, so it’s not hard to eyeball roughly where the minimum is if I sample enough. I can say very little about the noise. I’m more interested being able to approximate the optimum quickly (since simulation time adds up) than hitting it exactly. The approach taken in this paper based on a non-parametric tau test looks interesting.

badger Feb 26, 2014, 1:55 AM
0 points
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in reply to: Lumifer’s comment on: Open Thread February 25 - March 3
The parameter space in this current problem is only two dimensional, so I can eyeball a plausible region, sample at a higher rate there, and iterate by hand. In another project, I had something with an very high dimensional parameter space, so I figured it’s time I learn more about these techniques.

Any resources you can recommend on this topic then? Is there a list of common shortcuts anywhere?

badger Feb 25, 2014, 10:35 PM
0 points
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in reply to: Lumifer’s comment on: Open Thread February 25 - March 3
Not really. In this particular case, I’m minimizing how long it takes a simulation reach one state, so the distribution ends up looking lognormal- or Poisson-ish.

Edit: Seeing your added question, I don’t need an efficient estimator in the usual sense per se. This is more about how to search the parameter space in a reasonable way to find where the minimum is, despite the noise.

badger Feb 25, 2014, 10:08 PM
7 points
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on: Open Thread February 25 - March 3
Does anyone have advice on how to optimize the expectation of a noisy function? The naive approach I’ve used is to sample the function for a given parameter a decent number of times, average those together, and hope the result is close enough to stand in for the true objective function. This seems really wasteful though.

Most of the algorithms I’m coming (like modelling the objective function with gaussian process regression) would be useful, but are more high-powered than I need. Any simple techniques better than the naive approach? Any recommendations among sophisticated approaches?

badger Feb 25, 2014, 8:26 PM
2 points
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on: Single player extensive-form games as a model of UDT
Your description of incomplete information is off. What you give as the definition of incomplete information is one type of imperfect information, where nature is added as a player.

A game has incomplete information when one player has more information than another about payoffs. Since Harsanyi, incomplete information has been seen as a special case of imperfect information with nature randomly assigning types to each player according to a commonly known distribution and payoffs given types being commonly known.

badger Feb 25, 2014, 8:02 PM
4 points
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in reply to: Scott Garrabrant’s comment on: Single player extensive-form games as a model of UDT
The first option is standard. When the second interpretation comes up, those strategies are referred to as behavior strategies.

If every information set is visited at most once in the course of play, then the game satisfies no-absent-mindedness and every behavior strategy can be represented as a standard mixed strategy (but some mixed strategies don’t have equivalent behavior strategies).

Kuhn’s theorem says the game has perfect recall (roughly players never forget anything and there is a clear progression of time) if and only if mixed and behavior strategies are equivalent.

badger Feb 24, 2014, 11:38 PM
11 points
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in reply to: Randy_M’s comment on: Open Thread for February 18-24 2014
Haidt’s claim is that liberals rely on purity/sacredness relatively less often, but it’s still there. Some of the earlier work on the purity axis put heavy emphasis on sex or sin. Since then, Haidt has acknowledged that the difference between liberals and conservatives might even out if you add food or environmental concerns to purity.

badger Feb 24, 2014, 11:27 PM
2 points
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in reply to: James_Miller’s comment on: Open Thread for February 18-24 2014
Haidt acknowledges that liberals feel disgust at racism and that this falls under purity/sacredness (explicitly listing it in a somewhat older article on Table 1, pg 59). His claim is that liberals rely on the purity/sacredness scale relatively more often, not that they never engage it. Still, in your example, I’d expect the typical reaction to be anger at a fairness violation rather than disgust.

badger Feb 20, 2014, 2:18 AM
1 point
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in reply to: JQuinton’s comment on: Open Thread for February 18-24 2014
My guess is the person most likely to defend this criterion is a Popperian of some flavor, since precise explanations (as you define them) can be cleanly falsified.

While it’s nice when something is cleanly falsified, it’s not clear we should actively strive for precision in our explanations. An explanation that says all observations are equally likely is hard to disprove and hence hard to gather evidence for by conversation of evidence, but that doesn’t mean we should give it an extra penalty.

If all explanations have equal prior probability, then Bayesian reasoning will tend to favor the most precise explanations consistent with the evidence. Seeing a black marble is most likely when all the marbles in a collection are black. If you then found a red marble, that would definitely rule out the black collection (assuming they both had to come from the same one). The best candidate would then be one that is half each. Ultimately, this all comes back down to likelihoods though, so I’m not sure the idea of precision adds much.

badger Feb 19, 2014, 2:58 PM
3 points
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in reply to: eggman’s comment on: Open Thread for February 18-24 2014
I’ve used 1-2mg of nicotine (via gum) a few of times a month for a couple years. I previously used it a few times a week for a few months before getting a methylphenidate prescription for ADD. There hasn’t been any noticeable dependency, but I haven’t had that with other drugs either.

Using it, I feel more focused and more confident, in contrast to caffeine which tends to just leaves me jittery and methyphenidate which is better for focus but doesn’t have the slight positive emotion boost. Delivered via gum, the half-life is short (an hour at most). That’s not great for a day-to-day stimulant, but it’s useful when I need something at 6pm and methylphenidate would interfere with my sleep. The primary downside is occasional nausea. Now I’m wondering if patches would be longer-lasting and less nausea-inducing.

badger Feb 12, 2014, 3:33 AM
2 points
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in reply to: ChristianKl’s comment on: Useful Personality Tests
The first two links are from a public-domain pool of personality scales. Shorter versions of the Big Five are also available there. The original dark triad scale is free to use. I’m not exactly sure about the copyright status of items described in academic papers, but are presumably covered under fair use.

badger Feb 11, 2014, 8:22 PM
7 points
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in reply to: ChristianKl’s comment on: Useful Personality Tests
If this were to happen, here are some scales possibly worth including:
- Big Five personality traits and aspects, 100 items
- Need for order and perfectionism, 10 items each
- Dark triad (Machiavellianism, narcissism, psychopathy), 12 items
- ADHD (gated), 18 items
- Grit, 8 items

badger Jan 29, 2014, 5:10 PM
1 point
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in reply to: JQuinton’s comment on: Open Thread for January 8 − 16 2014
That example helps clarify. In the A/C situation, you and your brother aren’t really starting with a game. There isn’t a natural set of strategies you are each independently choosing from; instead you are selecting one temperature together. You could construct a game to help you two along in that joint decision, though. To solve the overall problem, there are two questions to be answered:
1. Given a set of outcomes and everyone’s preferences over the outcomes, which outcome should be chosen? This is studied in social choice theory, cake-cutting/fair division, and bargaining solutions.
2. Given an answer to the first question, how do you construct a game that implements the outcome that should be chosen? This is studied in mechanism design.
One possible solution: If everything is symmetric, the result should split the resource equally, either by setting the temperature halfway between your ideal and his ideal or alternating nights where you choose your ideals. With this as a starting point, flip a coin. The winner can either accept the equal split or make a new proposal of a temperature and a payment to the other person. The second person can accept the new proposal or make a new one. Alternate proposals until one is accepted. This is roughly the Rubinstein bargaining game implementing the Nash bargaining solution with transfers.

Another possible solution: Both submit bids between 0 and 1. Suppose the high bid is p. The person with the high bid proposes a temperature. The second person can either accept that outcome or make a new proposal. If the first player doesn’t accept the new proposal, the final outcome is the second player’s proposal with probability p and the status quo (say alternating nights) with probability 1-p. This is Moulin’s implementation of the Kalai-Smorodinsky bargaining solution.

badger Jan 24, 2014, 5:54 PM
2 points
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in reply to: Vaniver’s comment on: What should superrational players do in asymmetric games?
My two cents on usage: “Dominates” in that context is standard in economics, although I should have qualified it as “Pareto dominates”. We can distinguish between at least three levels of dominance: every agent strictly preferring one outcome over another, at least one agent strictly preferring it and all others weakly preferring it, and every agent weakly preferring it. I think common usage is to call the first “strict Pareto dominance”, the second “weak Pareto dominance”, and the third doesn’t comes up. Unqualified, “Pareto dominance” probably means “weak Pareto dominance”, but that’s by no means standard. Also, I interpret “between 2 and 14” as “in the open interval (2, 14)”.

Thanks for the input on possible confusions! Dominance does get heavily overloaded depending on what’s being ordered.

badger Jan 24, 2014, 4:20 PM
0 points
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in reply to: Benya’s comment on: What should superrational players do in asymmetric games?
Oh, I definitely agree. I meant it’s hard to hope for anything more inside environments with transferable/quasilinear utility. It’s a big assumption, but I’ve resigned myself to it somewhat since we need it for most of the positive results in mechanism design.