Science and Technology

Imprinted Brain Theory of Autism

Posted by Peter on January 14, 2009
Posted in: The Human Mind. Tagged: .

An unusual hypothesis about autism involves Genomic imprinting (“imbalances in the outcomes of intragenomic conflict between effects of maternally vs. paternally expressed genes.”).

It’s apparently somewhat well established that some regions of the brain are influenced more by paternal genes (the paternal brain), and some by maternally genes (the maternal brain).

The Imprinted Brain theory of autism says that autism results from the paternal brain being more developed, and the maternal brain being less developed, with an increased paternal brain causing Aspergers syndrome, and a reduced maternal brain causing more severe autism.

The father’s genes want the mother to invest more resources in a child than the mother’s genes do. Maternal genes have more desire for child to empathize with her and siblings to make childcare less costly. Paternal genes have more desire for competition between siblings over resources.

I had previously been impressed by a theory in the book Shadow Syndromes that involves a less developed cerebellum causing a slowness to shift one’s attention as a child, which makes one less likely to notice facial expressions. The Imprinted Brain theory can imply this (the cerebellum is one of the maternal brain areas which is underdeveloped).

The evidence is hard to summarize, but here’s an example:

autism increases with paternal (and maternal) age (Gillberg, 1980), and assisted reproduction via intracytoplasmic sperm injection (ICSI) may increase the risk for syndromes of dysregulated imprinting, including Angelman and Beckwith-Weideman (Paoloni-Giacobino & Chaillet, 2004; Waterland & Jirtle, 2004; Maher, 2005). Both paternal age and ICSI are expected to contribute to methylated-gene defects, which may include effects on brain-imprinted genes (Waterland & Jirtle, 2004; Malaspina et al., 2005).

I recommend reading the discussion section of the paper, which contains much more information than I can summarize.

The paper also mentions evidence that paranoid schizophrenia is an opposite of autism (involving a highly developed maternal brain) – schizophrenics are more likely than most people to notice/imagine that someone is looking at them (see (Mentalism and mechanism and The eyes have it).

Here is an apparently unrelated argument for schizophrenia and autism being opposites.

A Different Kind of Boy

Posted by Peter on January 7, 2009
Posted in: Book Reviews, The Human Mind. Tagged: .

Book review: A Different Kind of Boy: A Father’s Memoir on Raising a Gifted Child With Autism by Daniel Mont.
This book provides a clear and moving story of what it’s like to have a fairly autistic child. It reinforces my belief that autism (or at least some of the personalities classified as autistic) is one extreme of a range of human personalities. I was surprised at the extent to which Alex’s personality is an extreme version of the personality I had as a child.
The author demonstrates an unusual ability to treat his son as an equal for some purposes (such as logical reasoning) while simultaneously being aware that Alex finds it extremely hard to learn concepts most of us take for granted (e.g. the difference between lying and pretending).
Many of the problems people have interacting with Alex closely resemble the problems AI researchers discover when they try to translate an “obvious” concept into unambiguous language. But just when I thought the AI analogy provides a reliable guide, I noticed an exception – Alex finds long division harder than economic theory.

Convergence08

Posted by Peter on November 29, 2008
Posted in: Science and Technology. Tagged: , , , .

Convergence08 had an amazing number of interesting people in attendance. No one person stood out as unusually impressive – it was more that the average was unusually high for a 300 person gathering. I’ll list many small ideas, which partly reflects the fact that I was trying to sample a wide enough variety of sessions that I didn’t manage to absorb any one presentation in depth.
Genescient is a new company whose founders include SF author Greg Benford. It has a strain of fruit flies bred for lifespans more than 4 times normal, and has used their DNA to identify substances that might improve human lifespan. It sounds like they will soon offer dietary supplements which have little risk and a hope of slowing down aging by some hard to predict (probably small) amount.

Advice from Eliezer Yudkowsky (responding to a concern that transhumanists have few children): don’t reproduce until you can code your child from scratch.

Several ideas from a session run by Anders Sandberg:

  • AntiGroupware is designed to remove many social pressures from group decision-making
  • Once it’s easy to make copies of people, political campaigns will be run by a large number of copies. [This assumes that democracy can attempt to survive – are copies going to be denied votes?]
  • Politicians should be selected from losers of the game Diplomacy [It might be hard to keep them from deliberately losing, but with big incentives winning plus a low probability of any one loser becoming a politician, it might work.]

Ideas from a session run by Milton Huang:

  • Keeping Skype video connections open for hours at a time changes remote interactions between two people in ways that make them seem very different from telephone conversations, and more like being physically together
  • We should try to implement a way to transmit hugs remotely
  • We might be able to make people (especially those with autistic tendencies) experience more empathy via an “empathy machine” that measures and reports on what others are feeling

Global Catastrophic Risks conference

Posted by Peter on November 20, 2008
Posted in: Molecular Assemblers (Advanced Nanotech), Science and Technology. Tagged: , , , .

The Global Catastrophic Risks conference last Friday was a mix of good and bad talks.
By far the most provocative was Josh‘s talk about “the Weather Machine”. This would consist of small (under 1 cm) balloons made of material a few atoms thick (i.e. needed nanotechnology that won’t be available for a couple of decades) filled with hydrogen and having a mirror in the equatorial plane. They would have enough communications and orientation control to be individually pointed wherever the entity in charge of them wants. They would float 20 miles above the earth’s surface and form a nearly continuous layer surrounding the planet.
This machine would have a few orders of magnitude more power over atmospheric temperatures to compensate for the warming caused by greenhouse gasses this century, although it would only be a partial solution to the waste heat farther in the future that Freitas worries about in his discussion of the global hypsithermal limit.
The military implications make me wish it won’t be possible to make it as powerful as Josh claims. If 10 percent of the mirrors target one location, it would be difficult for anyone in the target area to survive. I suspect defensive mirrors would be of some use, but there would still be serious heating of the atmosphere near the mirrors. Josh claims that it could be designed with a deadman switch that would cause a snowball earth effect if the entity in charge were destroyed, but it’s not obvious why the balloons couldn’t be destroyed in that scenario. Later in the weekend Chris Hibbert raised concerns about how secure it would be against unauthorized people hacking into it, and I wasn’t reassured by Josh’s answer.

James Hughes gave a talk advocating world government. I was disappointed with his inability to imagine that that would result in power becoming too centralized. Nick Bostrom’s discussions of this subject are much more thoughtful.

Alan Goldstein gave a talk about the A-Prize and defining a concept called the carbon barrier to distinguish biological from non-biological life. Josh pointed out that as stated all life fit Goldstein’s definition of biological (since any information can be encoded in DNA). Goldstein modified his definition to avoid that, and then other people mentioned reports such as this which imply that humans don’t fall within Goldstein’s definition of biological due to inheritance of information through means other than DNA. Goldstein seemed unable to understand that objection.

Global Catastrophic Risks

Posted by Peter on September 25, 2008
Posted in: Artificial Intelligence, Book Reviews, Fermi Paradox, Molecular Assemblers (Advanced Nanotech). Tagged: , .

Book review: Global Catastrophic Risks by Nick Bostrom, and Milan Cirkovic.
This is a relatively comprehensive collection of thoughtful essays about the risks of a major catastrophe (mainly those that would kill a billion or more people).
Probably the most important chapter is the one on risks associated with AI, since few people attempting to create an AI seem to understand the possibilities it describes. It makes some implausible claims about the speed with which an AI could take over the world, but the argument they are used to support only requires that a first-mover advantage be important, and that is only weakly dependent on assumptions about that speed with which AI will improve.
The risks of a large fraction of humanity being killed by a super-volcano is apparently higher than the risk from asteroids, but volcanoes have more of a limit on their maximum size, so they appear to pose less risk of human extinction.
The risks of asteroids and comets can’t be handled as well as I thought by early detection, because some dark comets can’t be detected with current technology until it’s way too late. It seems we ought to start thinking about better detection systems, which would probably require large improvements in the cost-effectiveness of space-based telescopes or other sensors.
Many of the volcano and asteroid deaths would be due to crop failures from cold weather. Since mid-ocean temperatures are more stable that land temperatures, ocean based aquaculture would help mitigate this risk.
The climate change chapter seems much more objective and credible than what I’ve previously read on the subject, but is technical enough that it won’t be widely read, and it won’t satisfy anyone who is looking for arguments to justify their favorite policy. The best part is a list of possible instabilities which appear unlikely but which aren’t understood well enough to evaluate with any confidence.
The chapter on plagues mentions one surprising risk – better sanitation made polio more dangerous by altering the age at which it infected people. If I’d written the chapter, I’d have mentioned Ewald’s analysis of how human behavior influences the evolution of strains which are more or less virulent.
There’s good news about nuclear proliferation which has been under-reported – a fair number of countries have abandoned nuclear weapons programs, and a few have given up nuclear weapons. So if there’s any trend, it’s toward fewer countries trying to build them, and a stable number of countries possessing them. The bad news is we don’t know whether nanotechnology will change that by drastically reducing the effort needed to build them.
The chapter on totalitarianism discusses some uncomfortable tradeoffs between the benefits of some sort of world government and the harm that such government might cause. One interesting claim:

totalitarian regimes are less likely to foresee disasters, but are in some ways better-equipped to deal with disasters that they take seriously.

“Junk DNA” is important

Posted by Peter on September 14, 2008
Posted in: Miscellaneous. Tagged: , .

Most experts were surprised at the news that human DNA seems to contain less than 25000 genes.
Since then signs have emerged that the rest of the DNA (often called junk DNA is quite active, with about 80% of the DNA being transcribed into RNA even though only 1-2% constitutes protein-coding genes.
There’s a lot of mystery about what, if anything, most of that RNA does, but it’s not all junk. One such RNA molecule, HOTAIR, appears to control expression of some genes. RNA has an ability to fold into shapes that may rival proteins in their diversity, so there’s no good reason to think that creating proteins comes close to describing the set of functions that RNA performs.

Monkeyluv

Posted by Peter on August 30, 2008
Posted in: Book Reviews, The Human Mind. Tagged: , , , .

Book review: Monkeyluv: And Other Essays on Our Lives as Animals by Robert M. Sapolsky.
This collection of essays starts out by rehashing nature/nurture arguments that ought to be widely understood by now, but then becomes mostly entertaining and occasionally quite informative.
He mentions one interesting study which questions sexual selection arguments put forward by Geoffrey Miller and others about animals selecting mates with better genes. The study shows that female Mallards produce stronger offspring after mating with more attractive males because they invest more resources in those eggs, rather than because of anything that seems connected to the genes provided by the males.
He helps explain the attraction of gambling by describing experiments which show larger dopamine releases due to rewards that are most uncertain (the subject thinks they have a 50% chance of happening) than is released when there’s more certainty (e.g. either a 25% chance or a 75% chance) of the same reward.
One place where I was disappointed was when he described “repressive personalities”, which he made seem quite similar to Aspergers, and made me wonder whether I fit his description. “dislike novelty”? My reaction to novelty is sufficiently context-dependent that any answer is plausible. “prefer structure and predictability”? Yes and usually. “poor at expressing emotions or at reading the nuances of emotions in other people”? That’s me. “can tell you what they’re having for dinner two weeks from Thursday”? I could probably predict 5 days in advance with 50% accuracy, so I’m probably closer than most people. So I Googled and found another description (mentioning the same researcher that Sapolsky mentioned) in the Sciences and find descriptions of “repressive personality” that seem wildly different from me (“a strong personal need for social conformity” and “agreement with statements framed as absolutes, statements loaded with the words never and always”). Who wrote this competing description? Wait, it’s the same Sapolsky! It looks like his current description reuses a small piece of an older article with inadequate thought to whether it’s complete enough.

Archaic Science Fiction

Posted by Peter on August 17, 2008
Posted in: Book Reviews, Science and Technology.

F.M. Busby’s The Breeds of Man was written in 1988. Many of his expectations for what was then the future are surprising not just because they’re wrong, but because it took me a fair amount of effort to remember that back in 1988 I wouldn’t have dismissed them as silly.
Most of the book takes place in an unspecified year that is no earlier than 2005 and probably no later than 2020. One of the most striking features of the story is that a powerful person is able to exert pressure on the news media to kill a story that at least one reporter is working on. The story would have generated enough publicity that in 1988 it would have been somewhat doubtful whether it could have been suppressed, but it would have been the kind of possibility that in 1988 I would have expected to generate some entertaining debates. But today, the idea that the reporter couldn’t advance her career by taking the story to an alternate news channel seems too foreign for even a moderately crazy conspiracy theorist to propose.
The book is not particularly bad as science fiction goes, but it’s full of places where I’m almost shocked at how primitive the flow of information seems. And when I think back, I remember that for more than half my life I lived in that primitive world.

Human Accomplishment

Posted by Peter on August 12, 2008
Posted in: Book Reviews, Life, the Universe, and Everything, Science and Technology. Tagged: , .

Book review: Human Accomplishment: The Pursuit of Excellence in the Arts and Sciences, 800 B.C. to 1950 by Charles Murray.
I was reluctant to read this book but read it because a reading group I belong to selected it. I agree with most of what it says, but was underwhelmed by what it accomplished.
He has compiled an impressive catalog of people who have accomplished excellent feats in arts, science, and technology.
He has a long section arguing that the disproportionate number of dead white males in his list is not a result of bias. Most of this just repeats what has been said many times before. He appears do have done more than most to check authorities of other cultures to verify that their perspective doesn’t conflict with his. But that’s hard to do well (how many different languages does he read well enough to avoid whatever selection biases influence what’s available in English?) and hard for me to verify. He doesn’t ask how his choice of categories (astronomy, medicine, etc) bias his results (I suspect not much).
His most surprising claim is that the rate of accomplishment is declining. He convinced me that he is measuring something that is in fact declining, but didn’t convince me that what he measured is important. I can think of many other ways of trying to measure accomplishment: number of lives saved, number of people whose accomplishment was bought by a million people, number of people whose accomplishment created $100 million in revenues, the Flynn Effect, number of patents, number of peer-reviewed papers, or number of meta–innovations. All of these measures have nontrivial drawbacks, but they illustrate why I find his measure (acclaim by scholars) very incomplete. An incomplete measure may be adequate for conclusions that aren’t very sensitive to the choice of measure (such as the male/female ratio of important people), but when most measures fail to support his conclusion that the rate of accomplishment is declining, his failure to try for a more inclusive measure is disappointing.
His research appears careful to a casual reader, but I found one claim that was definitely not well researched. He thinks that “the practice of medicine became an unambiguous net plus for the patient” around the 1920s or 1930s. He cites no sources for this claim, and if he had found the best studies on the subject he’d see lots of uncertainty about whether it has yet become a net plus.

Why Humans Cooperate

Posted by Peter on July 10, 2008
Posted in: Book Reviews, The Human Mind. Tagged: , , .

Book review: Why Humans Cooperate: A Cultural and Evolutionary Explanation by Joseph Henrich, Natalie Henrich.
This book provides a clear and informative summary of the evolutionary theories that explain why people cooperate (but few novel ideas), and some good but unexciting evidence that provides a bit of support for the theories.
One nice point they make is that unconditional altruism discourages cooperation – it’s important to have some sort of reciprocity (possibly indirect) for a society to prevent non-cooperators from outcompeting cooperators.
The one surprising fact uncovered in their field studies is that people are more generous in the Dictator Game than in the Ultimatum Game (games where one player decides how to divide money between himself and another player; in the Ultimatum Game the second player can reject the division, in which case neither gets anything). It appears that the Ultimatum Game encourages people to think in terms of business-like interactions, but in the Dictator Game a noncompetitive mode of thought dominates.