= 27d567bc2d48d9f40e9ccc20ea370b15)
Thanks, nice work.
The comment: 13 points Hey 02 November 2011 09:01:09AM is maybe something you want to remove.
It seems that I am not one in a million. Pity.
At least you're not alone.
The cow needs more receptors, and more activators. However, this would lead one to expect the relationship of brain size to body size to follow a power-law with an exponent of 2/3 (for receptors, which are primarily on the skin); or of 1 (for activators, which might be in number proportional to volume). The actual exponent is 3/4. Scientists are still arguing over why.
West and Brown has done some work on this which seemed pretty solid to me when I read it a few months ago. The basic idea is that biological systems are designed in a fractal way which messes up the dimensional analysis.
From the abstract of http://jeb.biologists.org/cgi/content/abstract/208/9/1575:
We have proposed a set of principles based on the observation that almost all life is sustained by hierarchical branching networks, which we assume have invariant terminal units, are space-filling and are optimised by the process of natural selection. We show how these general constraints explain quarter power scaling and lead to a quantitative, predictive theory that captures many of the essential features of diverse biological systems. Examples considered include animal circulatory systems, plant vascular systems, growth, mitochondrial densities, and the concept of a universal molecular clock. Temperature considerations, dimensionality and the role of invariants are discussed. Criticisms and controversies associated with this approach are also addressed.
A Science article of theirs containing similar ideas: http://www.sciencemag.org/cgi/content/abstract/sci;284/5420/1677
Edit: A recent Nature article showing that there is systematic deviations from the power law, somewhat explainable with a modified version of the model of West and Brown:
http://www.nature.com/nature/journal/v464/n7289/abs/nature08920.html
In response to
Think Before You Speak (And Signal It)
Interesting idea.
I agree that trusting newly formed ideas is risky, but there are several reasons to convey them anyway (non-comprehensive listing):
To recruit assistance in developing and verifying them
To convey an idea that is obvious in retrospect, an idea you can be confident in immediately
To signal cleverness and ability to think on one's feet
To socially play with the ideas
What we are really after though is to asses how much weight to assign to an idea off the bat so we can calculate the opportunity costs of thinking about the idea in greater detail and asking for the idea to be fleshed out and conveyed fully. This overlaps somewhat with the confidence (context sensitive rules in determining) with which the speaker is conveying the idea. Also, how do you gauge how old an idea really is? Especially if it condenses gradually or is a simple combination out of very old parts? Still... some metric is better than no metric.
<Thought about for 1 minute. Written up in 5 minutes.>
To convey an idea that is obvious in retrospect, an idea you can be confident in immediately
Solutions to hard puzzles are good examples of these. NP-problems, where finding a solution is (believed to be) exponentially harder than checking the correctness of it, is the extreme case.
<Thought about 2 minutes, written up in 2.>
I didn't know that was possible, thanks. (Wow, a prior with integral=infinity! One that can't be reached as a posterior after any observation! How'd a Bayesian come by that? But seems to work regardless.) What would be a better example?
ETA: I believe the point raised in that comment still deserves an answer from Bayesians.
It's called an improper prior. There's been some argument about their use but they seldom lead to problems. The posteriors usually has much better behavior at infinity and when they don't, that's the theory telling us that the information doesn't determine the solution to the problem.
The observation that an improper prior cannot be obtain as a posterior distribution is kind of trivial. It is meant to represent a total lack of information w.r.t. some parameter. As soon you have made an observation you have more information than that.
"An ideal bayesian wouldn't..." I apologize, I'm not following.
I was dismissing votes not contributing new information. The order of the votes is partly deduced. Regarding the part that isn't deduced, there is no evidence to update on, and the prior is included - it's the (6:4) factor.
Would you mind posting what the ideal bayesian's calculations would look like?
[Sorry for not answering earlier, I didn't find the inbox until recently.]
I perhaps was a bit unclear, but when I say "ideal bayesian" I mean a mathematical construct that does full bayesian updating i.e. incorporates all prior knowledge into its calculations. This is of course impossible for anyone not extremely ignorant of the world, which is why I called it a minor point.
An ideal bayesian calculation would include massive deductive work on e.g. the psychology of voting, knowledge of the functioning of this community in particular etc.
My comment wasn't really an objection. To do a full bayesian calculation of a real world problem is comparable to using quantum mechanics for macroscopic systems. One must use approximations; the hard part is knowing when they break down.
In response to
Akrasia, hyperbolic discounting, and picoeconomics
I just have one question, it's so obvious but I don't remember it being asked anywhere.
Humans and all animals tested use hyperbolic discounting + hacks on top of it to deal with paradoxes. Why hasn't evolution implemented exponential discounting in any animal? Is it technically impossible the way brain works (perhaps by local optimum), or is hyperbolic discounting + hacks better in the real world than exponential discounting?
I think this is a far more fundamental problem than anything else about akrasia.
Reading the Wikipedia article on hyperbolic discounting it seems like there is some evidence for a quasi-hyperbolic discounting. Looking at the formula, the interpretation is exponential discounting for all future times considered but with a special treatment of the present.
How to explain this? It is not unlikely that the brain uses one system for thinking about now and another about the future. Considering the usual workings of evolution, the latter is most likely a much later feature than the former. Considering this, one could perhaps even argue that it would be surprising if there wasn't any differences between the systems.
There seems to be some literature referenced at the wiki article. I suggest looking into it if you are interested. I sadly don't have the time right now.
This is a project that I think really would profit from recruitment of a few psychologists with experience on creating personality test, IQ test or similarly. It sounds a bit like we're trying to create a new subfield here. Not that I want to sound discouraging, I think it is very important to get the ball rolling and even small, preliminary results could prove to be very useful, but there is probably enough material here to base quite a few academic careers on.
I'll have to agree with Kaj that a short survey is better for most purposes, but throwing out a long list of ideas first to later hone down to a more efficient one is a good idea.
In response to
Defense Against The Dark Arts: Case Study #1
I disagree with your conclusion on the grounds that I think you're interpreting the passage in a different way than the author intended it.
My interpretation is more along the lines of "Steve Jobs, on seeing the profound economic destitution in the East, examined his beliefs about human utility functions. Finding that Western values/practices seemed to promote utility better than Eastern values/practices in developing countries (and perhaps that they do even in developed countries), he decided that the East should adopt the West's values/practices."
I loved the dissection into multiple biases, and I agree with your dissection based on your reading of the passage, but I think the author is saying something different and more in line with the prevalent beliefs on Less Wrong.
I think you may very well be correct in your interpretation of the original authors intention. However, I think Yvain's is more spot on for the majority of the upvotes the comment got.
View more: Next
= b715d02e85f7b3b4ae65ca3d3e450868)
Subscribe to RSS Feed
= f037147d6e6c911a85753b9abdedda8d){kind=logo}
Took the survey.