All posts tagged genetics

Book review: Evolution’s Rainbow: Diversity, Gender, and Sexuality in Nature and People by Joan Roughgarden
This book provides some good descriptions of sexual and gender diversity in nature and in a variety of human cultures, and makes a number of valid criticisms of biases against diversity in the scientific community and in society at large.
Many of her attempts to criticize sexual selection theory are plausible criticisms of beliefs that don’t have much connection to sexual selection theory (e.g. the belief that all sexually reproducing organisms fall into one of two gender stereotypes).
Her more direct attacks on the theory amount to claiming that “almost all diversity is good” and ignoring the arguments of sexual selection theorists who describe traits that appear to indicate reduced evolutionary fitness (see Geoffrey Miller’s book The Mating Mind). She practically defines genetic defects out of existence. She tries to imply that biologists agree on her criteria for a “genetic defect”, but her criteria require that a “trait be deleterious under all conditions” (I suspect most biologists would say “average” instead of “all”), and that it reduce fitness by at least 5 percent.
Her “alternative” theory, social selection, may have some value as a supplement to sexual selection theory, but I see no sign that it explains enough to replace sexual selection theory.
She sometimes talks as if she were trying to explain the evolution of homosexuality, but when doing so she is referring to bisexuality, and doesn’t attempt to explain why an animal would be exclusively homosexual.
Her obsession with discrediting sexual selection comes from an exaggerated fear that the theory implies that most diversity is bad. This misrepresents sexual selection theory (which only says that some diversity represents a mix of traits with different fitnesses). It’s also a symptom of her desire to treat natural as almost a synonym for good (she seems willing to hate diversity if it’s created via genetic engineering).
She tries to imply that a number of traits (e.g. transsexualism) are more common than would be the case if they significantly reduced reproductive fitness, but her reasoning seems to depend on the assumption that those traits can only be caused by one possible mutation. But if there are multiple places in the genome where a mutation could produce the same trait, there’s no obvious limit to how common a low-fitness trait could be.
Her policy recommendations are of very mixed quality. She wants the FDA to regulate surgical and behavioral therapies the way it regulates drugs, and claims that would stop doctors from “curing” nondiseases such as gender dysphoria. But she doesn’t explain why she expects the FDA to be more tolerant of diversity than doctors. Instead, why not let the patient decide as much as possible whether to consider something a disease?

Book Review: Race, Evolution, and Behavior: A Life History Perspective by J. Philippe Rushton
Rushton has a plausible theory that some human populations are more k-selected than others. He presents lots of marginal-quality evidence, but that’s no substitute for what he should be able to show if his theory is true.
Much of the book is devoted to evidence about IQs and brain sizes, but he fails to provide much of an argument for his belief that k-selected humans ought to have higher intelligence. It’s easy to imagine that it might work that way. But I can come up with an alternative based on the sexual selection theory in Geoffrey Miller’s book The Mating Mind that seems about as plausible: r-selected humans have more of their reproductive fitness determined by success at competition for mates (as opposed to k-selected humans for whom child support has a higher contribution to reproductive fitness). Since The Mating Mind presents a strong argument that human intelligence evolved largely due to such competition for mates, it is easy to imagine that r-selected humans had stronger selection for the kind of social intelligence needed to compete for mates. Note that this theory suggests the intelligence of k-selected humans might be easier to measure via standardized tests than that of r-selected humans.
Rushton’s analysis of the genetic aspects of IQ makes the usual mistake of failing to do much to control for the effects of motivation on IQ scores (see pages 249-251 of Judith Rich Harris’s book The Nurture Assumption for evidence that this matters for Rushton’s goals).
He also devotes a good deal of space to evidence such as crime rates where it’s very hard to distinguish genetic from cultural differences, and there’s no reason to think he has succeeded in controlling for culture here.
Rushton mentions a number of other traits that are more directly connected to degree of k-selection and less likely to be culturally biased. It’s disappointing that he provides little evidence of the quality of the data he uses. The twinning data seem most interesting to me, as the high twin rates of the supposedly r-selected population follow quite clearly from his theory, it’s hard to come up with alternative theories that would explain such twinning rates, and the numbers he gives look surprisingly different from random noise. But Rushton says so little about these data that I can’t have much confidence that they come from representative samples of people. (He failed to detect problems with the widely used UN data on African AIDS rates, which have recently been shown to have been strongly biased by poor sampling methods, so it’s easy to imagine that he uses equally flawed data for more obscure differences). (Aside – the book’s index is poor enough that page 214, which is where he lists most of his references for the twinning data, is not listed under the entry for twins/twinning).
Rushton occasionally produces some interesting but irrelevant tidbits, such as that Darwin “affirmed human unity” by ending the debate over whether all humanity had a common origin, or that there’s evidence that “introverts are more punctual, absent less often, and stay longer at a job”.
Edward M. Miller has a theory that is similar to but slightly more convincing than Rushton’s in a paper titled Paternal Provisioning versus Mate Seeking in Human Populations.

Book Review: The God Gene : How Faith Is Hardwired into Our Genes by Dean H. Hamer
This book is entertaining but erratic. To start with, the title is misleading. The important parts of the book are about spirituality (as in what Buddhists seek), which has little connection with God or churches. He does a moderately good job of describing evidence that he has identified a gene that influences spirituality. He makes plausible claims that spirituality makes people happy (that part of the book resembles the works of Csikszentmihalyi and Seligman). He makes a half-hearted attempt to argue that spirituality has evolutionary advantages which isn’t very convincing by itself, but in combination with the sexual selection arguments in Miller’s book The Mating Mind it becomes moderately plausible.
About halfway through the book, he runs out of things to say on those subjects and proceeds to wander through a bunch of marginally related subjects.
His descriptions of psilocybin, prozac, and ecstasy were interesting enough to make me want to learn more about those and similar drugs.
His claims that placebos are effective seem very exaggerated (see this abstract).

Book Review: The Blank Slate : The Denial of Human Nature and Modern Intellectual Life by Steven Pinker
Pinker makes a good case that there’s a widespread bias toward a blank-slate world-view. But when dealing with serious scientific literature, his attempts to find clearcut enemies seem mistaken.
Pinker’s claim that “The second scientific defense of the Blank Slate comes from connectionism” is pretty puzzling. This “defense” consists of modeling the mind as “a general-purpose learning device”. But the books that Pinker references (Rethinking Innateness, and Parallel Distributed Processing), are both careful to point out why their models are completely consistent with the kind of genetic influences on behavior that evolutionary psychologists are talking about. Their disagreements with Pinker seem to be at most about how those influences are implemented, and even there I can’t find anything in Pinker’s arguments that clearly rejects what the connectionists believe.
Pinker’s attacks on Gould’s quasi-defense of the blank slate mainly convinced me that Gould didn’t want to think clearly about the subject, probably because he considered that any mechanistic explanation of the mind (genetic or environmental) was demeaning.
Pinker’s arguments that it’s silly to believe in the tabula rasa and noble savage world-views are eloquent and compelling, but his response to the “it’s demeaning” attitudes will convince fewer people, because he ignores the very real benefits of holding an unrealistically high opinion of one’s self (overestimating one’s abilities seems to be an effective means of advertising one’s strengths). To those who want to portray themselves as angelic or as wiser than software of the future, an accurate model of the mind is genuinely demeaning.
Pinker seems somewhat inconsistent about how important it is to know whether the mind is a blank slate.
On pages x – xi he says “the conviction that humanity could be reshaped by massive social engineering projects led to some of the greatest atrocities in history.” But in the chapter on fear of inequality, he claims (more convincingly), while defending his views from the charge they will encourage Nazism, that the differences between Nazi beliefs in genetic superiority and the blank slate viewpoints of Stalin and the Khmer Rouge didn’t have much effect on whether those tyrannies engaged in genocide – it was the greater tendency to divide people into in-groups and out-groups that best distinguishes the worst of the genocidal tyrants.
Pinker exaggerates the importance of finding the correct answer to the nature-nurture debate in other ways as well (I suppose we shouldn’t be surprised that an author overestimates the importance of what he’s selling).
He gives examples such as forcing people to live in drab cement boxes (as if their taste for a more natural surrounding could be reversed by social engineers), or releasing psychopaths (because societal problems caused their insanity).
But a genetic component to these behaviors doesn’t prove that they can’t be altered (I have genes for brown hair – does that mean I can’t dye my hair blue?). It only gives hints as to why they might be difficult to alter.
It sure looks like careful scientific studies of whether we knew how to alter these behaviors would be a more reliable way of debunking the faulty conclusions.

Book Review: Entrepreneurial Economics: Bright Ideas from the Dismal Science, edited by Alexander Tabarrok

This collection of papers has a bunch of very good ideas.
The patent buyouts chapter shows how most patents could be put into the public domain (fixing some problems associated with monopoly) while also increasing the incentives for innovation (at least in areas such as drugs where the patent system works moderately well). Two minor weaknesses in the paper: it ought to explain why this is a better use of money than funding research directly (I expect this could be done by analyzing the incentives and track record of small startup drug companies versus nonprofit/government researchers). The joint randomization for substitutes works well if there’s unlimited money to buy patents, but if a patentholder can make joint patents too expensive to buy by falsely claiming that its patent is a substitute, then it’s hard to analyze whether problems result (although I’m fairly sure they could be dealt with).
The chapter on decision markets (aka idea futures) provides some hints on how many of the problems with democracy could be fixed. Hopefully this will encourage readers to seek out his more thorough argument.
The time-consistent health insurance proposal describes a good free-market alternative solution to many of the problems that government-run insurance proposals claim to address.
The chapter on gene insurance would address additional problems with people born with genes that scare insurers, but only if it were possible to require buying this insurance prior before an infants genes get tested for defects. But it’s unclear how such a requirement can be enforced – it seems possible that a mother will often be able to get a fetus tested secretly before the government realizes it’s time for the child to get insured.
The section on organ shortages provides some interesting arguments that the medical establishment profits from the shortage of organs created by laws against the sale of organs.
The chapter on securities regulation is too longwinded but contains good evidence that competition between securities regulators will help investors.