Science and Technology

Financial Procrastination

Posted by Peter on August 4, 2016
Posted in: Investing, The Human Mind. Tagged: , , , , , .

Why do people knowingly follow bad investment strategies?

I won’t ask (in this post) about why people hold foolish beliefs about investment strategies. I’ll focus on people who intend to follow a decent strategy, and fail. I’ll illustrate this with a stereotype from a behavioral economist (Procrastination in Preparing for Retirement):[1]

For instance, one of the authors has kept an average of over $20,000 in his checking account over the last 10 years, despite earning an average of less than 1% interest on this account and having easy access to very liquid alternative investments earning much more.

A more mundane example is a person who holds most of their wealth in stock of a single company, for reasons of historical accident (they acquired it via employee stock options or inheritance), but admits to preferring a more diversified portfolio.

An example from my life is that, until this year, I often borrowed money from Schwab to buy stock, when I could have borrowed at lower rates in my Interactive Brokers account to do the same thing. (Partly due to habits that I developed while carelessly unaware of the difference in rates; partly due to a number of trivial inconveniences).

Behavioral economists are somewhat correct to attribute such mistakes to questionable time discounting. But I see more patterns than such a model can explain (e.g. people procrastinate more over some decisions (whether to make a “boring” trade) than others (whether to read news about investments)).[2]

Instead, I use CFAR-style models that focus on conflicting motives of different agents within our minds.

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Smart Animals?

Posted by Peter on July 21, 2016
Posted in: Book Reviews, The Human Mind. Tagged: , , .

Book review: Are We Smart Enough to Know How Smart Animals Are?, by Frans de Waal.

This book is primarily about discrediting false claims of human uniqueness, and showing how easy it is to screw up evaluations of a species’ cognitive abilities. It is best summarized by the cognitive ripple rule:

Every cognitive capacity that we discover is going to be older and more widespread than initially thought.

De Waal provides many anecdotes of carefully designed experiments detecting abilities that previously appeared to be absent. E.g. asian elephants failed mirror tests with small, distant mirrors. When experimenters dared to put large mirrors close enough for the elephants to touch, some of them passed the test.

Likewise, initial observations of behaviorist humans suggested they were rigidly fixated on explaining all behavior via operant conditioning. Yet one experimenter managed to trick a behaviorist into demonstrating more creativity, by harnessing the one motive that behaviorists prefer over their habit of advocating operant conditioning: their desire to accuse people of recklessly inferring complex cognition.

De Waal seems moderately biased toward overstating cognitive abilities of most species (with humans being one clear exception to that pattern).

At one point he gave me the impression that he was claiming elephants could predict where a thunderstorm would hit days in advance. I checked the reference, and what the elephants actually did was predict the arrival of the wet season, and respond with changes such as longer steps (but probably not with indications that they knew where thunderstorms would hit). After rereading de Waal’s wording, I decided it was ambiguous. But his claim that elephants “hear thunder and rainfall hundreds of miles away” exaggerates the original paper’s “detected … at distances greater than 100 km … perhaps as much as 300 km”.

But in the context of language, de Waal switches to downplaying reports of impressive abilities. I wonder how much of that is due to his desire to downplay claims that human minds are better, and how much of that is because his research isn’t well suited to studying language.

I agree with the book’s general claims. The book provides evidence that human brains embody only small, somewhat specialized improvements on the cognitive abilities of other species. But I found the book less convincing on that subject than some other books I’ve read recently. I suspect that’s mainly due to de Waal’s focus on anecdotes that emphasize what’s special about each species or individual. Whereas The Human Advantage rigorously quantifies important ways in which human brains are just a bigger primate brain (but primate brains are special!). Or The Secret of our Success (which doesn’t use particularly rigorous methods) provides a better perspective, by describing a model in which ape minds evolve to human minds via ordinary, gradual adaptations to mildly new environments.

In sum, this book is good at explaining the problems associated with research into animal cognition. It is merely ok at providing insights about how smart various species are.

Made-Up Minds

Posted by Peter on June 20, 2016
Posted in: Artificial Intelligence, Book Reviews, The Human Mind. Tagged: .

Book review: Made-Up Minds: A Constructivist Approach to Artificial Intelligence, by Gary L. Drescher.

It’s odd to call a book boring when it uses the pun “ontology recapitulates phylogeny”[1]. to describe a surprising feature of its model. About 80% of the book is dull enough that I barely forced myself to read it, yet the occasional good idea persuaded me not to give up.

Drescher gives a detailed model of how Piaget-style learning in infants could enable them to learn complex concepts starting with minimal innate knowledge.
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AGI Timelines

Posted by Peter on June 8, 2016
Posted in: Artificial Intelligence, Economics. Tagged: , , , .

One of most important assumptions in The Age of Ems is that non-em AGI will take a long time to develop.

1.

Scott Alexander at SlateStarCodex complains that Robin rejects survey data that uses validated techniques, and instead uses informal surveys whose results better fit Robin’s biases [1]. Robin clearly explains one reason why he does that: to get the outside view of experts.

Whose approach to avoiding bias is better?

  • Minimizing sampling error and carefully documenting one’s sampling technique are two of the most widely used criteria to distinguish science from wishful thinking.
  • Errors due to ignoring the outside view have been documented to be large, yet forecasters are reluctant to use the outside view.

So I rechecked advice from forecasting experts such as Philip Tetlock and Nate Silver, and the clear answer I got was … that was the wrong question.

Tetlock and Silver mostly focus on attitudes that are better captured by the advice to be a fox, not a hedgehog.

The strongest predictor of rising into the ranks of superforecasters is perpetual beta, the degree to which one is committed to belief updating and self-improvement.

Tetlock’s commandment number 3 says “Strike the right balance between inside and outside views”. Neither Tetlock or Silver offer hope that either more rigorous sampling of experts or dogmatically choosing the outside view over the inside view help us win a forecasting contest.

So instead of asking who is right, we should be glad to have two approaches to ponder, and should want more. (Robin only uses one approach for quantifying the time to non-em AGI, but is more fox-like when giving qualitative arguments against fast AGI progress).

2.

What Robin downplays is that there’s no consensus of the experts on whom he relies, not even about whether progress is steady, accelerating, or decelerating.

Robin uses the median expert estimate of progress in various AI subfields. This makes sense if AI progress depends on success in many subfields. It makes less sense if success in one subfield can make the other subfields obsolete. If “subfield” means a guess about what strategy best leads to intelligence, then I expect the median subfield to be rendered obsolete by a small number of good subfields [2]. If “subfield” refers to a subset of tasks that AI needs to solve (e.g. vision, or natural language processing), then it seems reasonable to look at the median (and I can imagine that slower subfields matter more). Robin appears to use both meanings of “subfield”, with fairly similar results for each, so it’s somewhat plausible that the median is informative.

3.

Scott also complains that Robin downplays the importance of research spending while citing only a paper dealing with government funding of agricultural research. But Robin also cites another paper (Ulku 2004), which covers total R&D expenditures in 30 countries (versus 16 countries in the paper that Scott cites) [3].

4.

Robin claims that AI progress will slow (relative to economic growth) due to slowing hardware progress and reduced dependence on innovation. Even if I accept Robin’s claims about these factors, I have trouble believing that AI progress will slow.

I expect higher em IQ will be one factor that speeds up AI progress. Garrett Jones suggests that a 40 IQ point increase in intelligence causes a 50% increase in a country’s productivity. I presume that AI researcher productivity is more sensitive to IQ than is, say, truck driver productivity. So it seems fairly plausible to imagine that increased em IQ will cause more than a factor of two increase in the rate of AI progress. (Robin downplays the effects of IQ in contexts where a factor of two wouldn’t much affect his analysis; he appears to ignore them in this context).

I expect that other advantages of ems will contribute additional speedups – maybe ems who work on AI will run relatively fast, maybe good training/testing data will be relatively cheap to create, or maybe knowledge from experimenting on ems will better guide AI research.

5.

Robin’s arguments against an intelligence explosion are weaker than they appear. I mostly agree with those arguments, but I want to discourage people from having strong confidence in them.

The most suspicious of those arguments is that gains in software algorithmic efficiency “remain surprisingly close to the rate at which hardware costs have fallen. This suggests that algorithmic gains have been enabled by hardware gains”. He cites only (Grace 2013) in support of this. That paper doesn’t comment on whether hardware changes enable software changes. The evidence seems equally consistent with that or with the hypothesis that both are independently caused by some underlying factor. I’d say there’s less than a 50% chance that Robin is correct about this claim.

Robin lists 14 other reasons for doubting there will be an intelligence explosion: two claims about AI history (no citations), eight claims about human intelligence (one citation), and four about what causes progress in research (with the two citations mentioned earlier). Most of those 14 claims are probably true, but it’s tricky to evaluate their relevance.

Conclusion

I’d say there’s maybe a 15% chance that Robin is basically right about the timing of non-em AI given his assumptions about ems. His book is still pretty valuable if an em-dominated world lasts for even one subjective decade before something stranger happens. And “something stranger happens” doesn’t necessarily mean his analysis becomes obsolete.

Footnotes

[1] – I can’t find any SlateStarCodex complaint about Bostrom doing something in Superintelligence that’s similar to what Scott accuses Robin of, when Bostrom’s survey of experts shows an expected time of decades for human-level AI to become superintelligent. Bostrom wants to focus on a much faster takeoff scenario, and disagrees with the experts, without identifying reasons for thinking his approach reduces biases.

[2] – One example is that genetic algorithms are looking fairly obsolete compared to neural nets, now that they’re being compared on bigger problems than when genetic algorithms were trendy.

Robin wants to avoid biases from recent AI fads by looking at subfields as they were defined 20 years ago. Some recent changes in AI are fads, but some are increased wisdom. I expect many subfields to be dead ends, given how immature AI was 20 years ago (and may still be today).

[3] – Scott quotes from one of three places that Robin mentions this subject (an example of redundancy that is quite rare in the book), and that’s the one place out of three where Robin neglects to cite (Ulku 2004). Age of Em is the kind of book where it’s easy to overlook something important like that if you don’t read it more carefully than you’d read a normal book.

I tried comparing (Ulku 2004) to the OECD paper that Scott cites, and failed to figure out whether they disagree. The OECD paper is probably consistent with Robin’s “less than proportionate increases” claim that Scott quotes. But Scott’s doubts are partly about Robin’s bolder prediction that AI progress will slow down, and academic papers don’t help much in evaluating that prediction.

If you’re tempted to evaluate how well the Ulku paper supports Robin’s views, beware that this quote is one of its easier to understand parts:

In addition, while our analysis lends support for endogenous growth theories in that it confirms a significant relationship between R&D stock and innovation, and between innovation and per capita GDP, it lacks the evidence for constant returns to innovation in terms of R&D stock. This implies that R&D models are not able to explain sustainable economic growth, i.e. they are not fully endogenous.

The Age of Em

Posted by Peter on May 24, 2016
Posted in: Artificial Intelligence, Book Reviews, Economics, Miscellaneous, Virtual Worlds. Tagged: , , , , .

Book review: The Age of Em: Work, Love and Life when Robots Rule the Earth, by Robin Hanson.

This book analyzes a possible future era when software emulations of humans (ems) dominate the world economy. It is too conservative to tackle longer-term prospects for eras when more unusual intelligent beings may dominate the world.

Hanson repeatedly tackles questions that scare away mainstream academics, and gives relatively ordinary answers (guided as much as possible by relatively standard, but often obscure, parts of the academic literature).

Assumptions

Hanson’s scenario relies on a few moderately controversial assumptions. The assumptions which I find most uncertain are related to human-level intelligence being hard to understand (because it requires complex systems), enough so that ems will experience many subjective centuries before artificial intelligence is built from scratch. For similar reasons, ems are opaque enough that it will be quite a while before they can be re-engineered to be dramatically different.

Hanson is willing to allow that ems can be tweaked somewhat quickly to produce moderate enhancements (at most doubling IQ) before reaching diminishing returns. He gives somewhat plausible reasons for believing this will only have small effects on his analysis. But few skeptics will be convinced.

Some will focus on potential trillions of dollars worth of benefits that higher IQs might produce, but that wealth would not much change Hanson’s analysis.

Others will prefer an inside view analysis which focuses on the chance that higher IQs will better enable us to handle risks of superintelligent software. Hanson’s analysis implies we should treat that as an unlikely scenario, but doesn’t say what we should do about modest probabilities of huge risks.

Another way that Hanson’s assumptions could be partly wrong is if tweaking the intelligence of emulated Bonobos produces super-human entities. That seems to only require small changes to his assumptions about how tweakable human-like brains are. But such a scenario is likely harder to analyze than Hanson’s scenario, and it probably makes more sense to understand Hanson’s scenario first.

Wealth

Wages in this scenario are somewhat close to subsistence levels. Ems have some ability to restrain wage competition, but less than they want. Does that mean wages are 50% above subsistence levels, or 1%? Hanson hints at the former. The difference feels important to me. I’m concerned that sound-bite versions of book will obscure the difference.

Hanson claims that “wealth per em will fall greatly”. It would be possible to construct a measure by which ems are less wealthy than humans are today. But I expect it will be at least as plausible to use a measure under which ems are rich compared to humans of today, but have high living expenses. I don’t believe there’s any objective unit of value that will falsify one of those perspectives [1].

Style / Organization

The style is more like a reference book than a story or an attempt to persuade us of one big conclusion. Most chapters (except for a few at the start and end) can be read in any order. If the section on physics causes you to doubt whether the book matters, skip to chapter 12 (labor), and return to the physics section later.

The style is very concise. Hanson rarely repeats a point, so understanding him requires more careful attention than with most authors.

It’s odd that the future of democracy gets less than twice as much space as the future of swearing. I’d have preferred that Hanson cut out a few of his less important predictions, to make room for occasional restatements of important ideas.

Many little-known results that are mentioned in the book are relevant to the present, such as: how the pitch of our voice affects how people perceive us, how vacations affect productivity, and how bacteria can affect fluid viscosity.

I was often tempted to say that Hanson sounds overconfident, but he is clearly better than most authors at admitting appropriate degrees of uncertainty. If he devoted much more space to caveats, I’d probably get annoyed at the repetition. So it’s hard to say whether he could have done any better.

Conclusion

Even if we should expect a much less than 50% chance of Hanson’s scenario becoming real, it seems quite valuable to think about how comfortable we should be with it and how we could improve on it.

Footnote

[1] – The difference matters only in one paragraph, where Hanson discusses whether ems deserve charity more than do humans living today. Hanson sounds like he’s claiming ems deserve our charity because they’re poor. Most ems in this scenario are comfortable enough for this to seem wrong.

Hanson might also be hinting that our charity would be effective at increasing the number of happy ems, and that basic utilitarianism says that’s preferable to what we can do by donating to today’s poor. That argument deserves more respect and more detailed analysis.

Probably Approximately Correct

Posted by Peter on May 24, 2016
Posted in: Artificial Intelligence, Book Reviews. Tagged: .

Book review: Probably Approximately Correct: Nature’s Algorithms for Learning and Prospering in a Complex World, by Leslie Valiant.

This book provides some nonstandard perspectives on machine learning and evolution, but doesn’t convince me there’s much advantage to using those perspectives. I’m unsure how much of that is due to his mediocre writing style. He often seems close to saying something important, but never gets there.

He provides a rigorous meaning for the concept of learnability. I suppose that’s important for something, but I can’t recall what.

He does an ok job of explaining how evolution is a form of learning, but Eric Baum’s book What is Thought? explains that idea much better.

The last few chapters, where he drifts farther from his areas of expertise, are worse. Much of what he says there only seems half-right at best.

One example is his suggestion that AI researchers ought to put a lot of thought into how teaching materials are presented (similar to how schools are careful to order a curriculum, from simple to complex concepts). I doubt that that reflects a reasonable model of human learning: children develop an important fraction of their intelligence before school age, with little guidance for the order in which they should learn concepts (cf. Piaget’s theory of cognitive development); and unschooled children seem to choose their own curriculum.

My impression of recent AI progress suggests that a better organized “curriculum” is even farther from being cost-effective there – progress seems to be coming more from better ways of incorporating unsupervised learning.

I’m left wondering why anyone thinks the book is worth reading.

The Human Advantage

Posted by Peter on April 17, 2016
Posted in: Book Reviews, The Human Mind. Tagged: , , , , .

Book review: The Human Advantage: A New Understanding of How Our Brain Became Remarkable, by Suzana Herculano-Houzel.

I used to be uneasy about claims that the human brain was special because it is large for our body size: relative size just didn’t seem like it could be the best measure of whatever enabled intelligence.

At last, Herculano-Houzel has invented a replacement for that measure. Her impressive technique for measuring the number of neurons in a brain has revolutionized this area of science.

We can now see an important connection between the number of cortical neurons and cognitive ability. I’m glad that the book reports on research that compares the cognitive abilities of enough species to enable moderately objective tests of the relevant hypotheses (although the research still has much room for improvement).

We can also see that the primate brain is special, in a way that enables large primates to be smarter than similarly sized nonprimates. And that humans are not very special for a primate of our size, although energy constraints make it tricky for primates to reach our size.

I was able to read the book quite quickly. Much of it is arranged in an occasionally suspenseful story about how the research was done. It doesn’t have lots of information, but the information it does have seems very new (except for the last two chapters, where Herculano-Houzel gets farther from her area of expertise).

Added 2016-08-25:
Wikipedia has a List of animals by number of neurons which lists the long-finned pilot whale as having 37.2 billion cortical neurons, versus 21 billion for humans.

The paper reporting that result disagrees somewhat with Herculano-Houzel:

Our results underscore that correlations between cognitive performance and absolute neocortical neuron numbers across animal orders or classes are of limited value, and attempts to quantify the mental capacity of a dolphin for cross-species comparisons are bound to be controversial.

But I don’t see much of an argument against the correlation between intelligence and cortical neuron numbers. The lack of good evidence about long-finned pilot whale intelligence mainly implies we ought to be uncertain.

The Secret of Our Success

Posted by Peter on April 13, 2016
Posted in: Book Reviews, The Human Mind. Tagged: , .

Book review: The Secret of Our Success: How Culture Is Driving Human Evolution, Domesticating Our Species, and Making Us Smarter, by Joseph Henrich.

This book provides a clear explanation of how an ability to learn cultural knowledge made humans evolve into something unique over the past few million years. It’s by far the best book I’ve read on human evolution.

Before reading this book, I thought human uniqueness depended on something somewhat arbitrary and mysterious which made sexual selection important for human evolution, and wondered whether human language abilities depended on some lucky mutation. Now I believe that the causes of human uniqueness were firmly in place 2-3 million years ago, and the remaining arbitrary events seem much farther back on the causal pathway (e.g. what was unique about apes? why did our ancestors descend from trees 4.4 million years ago? why did the climate become less stable 3 million years ago?)

Human language now seems like a natural byproduct of previous changes, and probably started sooner (and developed more gradually) than many researchers think.

I used to doubt that anyone could find good evidence of cultures that existed millions of years ago. But Henrich provides clear explanations of how features such as right-handedness and endurance running demonstrate important milestones in human abilities to generate culture.

Henrich’s most surprising claim is that there’s an important sense in which individual humans are no smarter than other apes. Our intellectual advantage over apes is mostly due to a somewhat special-purpose ability to combine our individual brains into a collective intelligence. His evidence on this point is weak, but it’s plausible enough to be interesting.

Henrich occasionally exaggerates a bit. The only place where that bothered me was where he claimed that heart attack patients who carefully adhered to taking placebos were half as likely to die as patients who failed to reliably take placebos. The author wants to believe that demonstrates the power of placebos. I say the patient failure to take placebos was just a symptom of an underlying health problem (dementia?).

I’m a bit surprised at how little Robin Hanson says about the Henrich’s main points. Henrich suggests that there’s cultural pressure to respect high-status people, for reasons that are somewhat at odds with Robin’s ally/coalition based reasons. Henrich argues that knowledge coming from high-status people, at least in hunter-gatherer societies, tended to be safer than knowledge from more directly measurable evidence. The cultural knowledge that accumulates over many generations aggregates information that could not be empirically acquired in a short time.

So Henrich implies it’s reasonable for people to be confused about whether evidence based medicine embodies more wisdom than eminence based medicine. Traditional culture has become less valuable recently due to the rapid changes in our environment (particularly the technology component of our environment), but cultures that abandoned traditions too readily were often hurt by consequences which take decades to observe.

I got more out of this book than a short review can describe (such as “How Altruism is like a Chili Pepper”). Here’s a good closing quote:

we are smart, but not because we stand on the shoulders of giants or are giants ourselves. We stand on the shoulders of a very large pyramid of hobbits.

Observing Neuron Behavior

Posted by Peter on January 15, 2016
Posted in: Miscellaneous. Tagged: , , .

Connectomes are not sufficient by themselves to model brain behavior. Brain modeling has been limited more by the need for good information about the dynamic behavior of individual neurons.

The paper Whole-brain calcium imaging with cellular resolution in freely behaving Caenorhabditis elegans looks like an important step toward overcoming this limitation. The authors observed the behavior of many individual neurons in a moving nematode.

They still can’t reliably map the neurons they observed to standard C. elegans neuron names:

The neural position validation experiments presented here, however, have led us to conclude that worm-to-worm variability in neuronal position in the head is large enough to pose a formidable challenge for neuron identification.

But there are enough hints about which neurons do what that I’m confident this problem can be solved if enough effort is devoted to it.

My biggest uncertainty concerns applying this approach to mammalian brains. Mammalian brains aren’t transparent enough to be imaged this way. Are C. elegans neurons similar enough that we can just apply the same models to both? I suspect not.

Hive Mind

Posted by Peter on January 2, 2016
Posted in: Book Reviews, The Flynn Effect. Tagged: , , .

Book review: Hive Mind: How your nation’s IQ matters so much more than your own, by Garett Jones.

Hive Mind is a solid and easy to read discussion of why high IQ nations are more successful than low IQ nations.

There’s a pretty clear correlation between national IQ and important results such as income. It’s harder to tell how much of the correlation is caused by IQ differences. The Flynn Effect hints that high IQ could instead be a symptom of increased wealth.

The best evidence for IQ causing wealth (more than being caused by wealth) is that Hong Kong and Taiwan had high IQs back in the 1960s, before becoming rich.

Another piece of similar evidence (which Hive Mind doesn’t point to) is that Saudi Arabia is the most conspicuous case of a country that became wealthy via luck. Its IQ is lower than countries of comparable wealth, and lower than neighbors of similar culture/genes.

Much of the book is devoted to speculations about how IQ could affect a nation’s success.

High IQ is associated with more patience, probably due to better ability to imagine the future:

Imagine two societies: one in which the future feels like a dim shadow, the other in which the future seems a real as now. Which society will have more restaurants that care about repeat customers? Which society will have more politicians who turn down bribes because they worry about eventually getting caught?

Hive Mind describes many possible causes of the Flynn Effect, without expressing much of a preference between them. Flynn’s explanation still seems strongest to me. The most plausible alternative that Hive Mind mentions is anxiety and stress from poverty-related problems distracting people during tests (and possibly also from developing abstract cognitive skills). But anxiety / stress explanations seem less likely to produce the Hong Kong/Taiwan/Saudi Arabia results.

Hive Mind talks about the importance of raising national IQ, especially in less-developed countries. That goal would be feasible if differences in IQ were mainly caused by stress or nutrition. Flynn’s cultural explanation points to causes that are harder for governments or charities to influence (how do you legislate an increased desire to think abstractly?).

What about the genetic differences that contribute to IQ differences? The technology needed to fix that contributing factor to low IQs is not ready today, but looks near enough that we should pay attention. Hive Mind implies [but avoids saying] that potentially large harm from leaving IQ unchanged could outweigh the risks of genetic engineering. Fears about genetic engineering of IQ often involve fears of competition, but Hive Mind shows that higher IQ means more cooperation. More cooperation suggests less war, less risk of dangerous nanotech arms races, etc.

It shouldn’t sound paradoxical to say that aggregate IQ matters more than individual IQ. It should start to seem ordinary if more people follow the example of Hive Mind and focus more attention on group success than on individual success as they relate to IQ.