Monday, November 30, 2009

Richard Powers, Generosity (2009)

Two years ago, I read a wonderfully conceived novel by Richard Powers entitled The Echo Maker. Introducing his readers to some of the marvels of neuroscience and our current understanding of the human brain as revealed by what we learn from brain injuries, Powers weaves science and storytelling in a thoughtful way. My only criticism of the novel was that it was about 30 or 40 pages too long, which is not a criticism of lengthy novels but a reflection of Powers' style to discuss non-fiction science through fictional dialogue: as fascinating as the material may be, it is not always the stuff of real conversation. Powers has been criticized for perhaps writing too much, and not leaving enough to the reader to figure out what is going on. When his next novel came along, however, I jumped at the chance to read more from the creative mind of Richard Powers.

In Generosity - An Enhancement, Powers visits the mind-body problem of feelings --- in this case the feeling of euphoria --- and whether there is a genetic basis for happiness or bliss that the medical research community might be able to exploit and transform our humanness. To tell this story, Powers calls upon a literary tool that he employed in the The Echo Maker -- a scientist who is capable of talking to the public through popular media. In The Echo Maker, it was Dr. Gerald Weber, a character modeled after neurologist Oliver Sacks who writes popular books based on his own medical experiences, including the book Awakenings that later earned an Academy Award as a film. In Generosity, Powers brings us Dr. Thomas Kurton, who comfortably appears on popular science television programs to explain his latest research --- cynically, to stimulate the next round of venture capital that is needed to fund his continuing research program that has yet to develop anything practical --- and who comfortably appears on a Chicago-based Oprah-like talk show touting the potential of genomics to enhance our life. There are other parallels between the two novels as well: there is a "patient," who is worth our studying, and there are people who are genuinely concerned for the welfare of the "patient." These characters paint the humanist landscape that is cast beside the scientific data and medical mysteries looking to be explained and solved.

While both Generosity and The Echo Maker touch on topics that have been addressed in previous posts about the brain, the hot topic here is the idea that there might be a gene controlling complex behavior. Framing the issue, Powers fictionalizes about a Nobel laureate who writes in "a much reproduced Guardian op-ed: 'We must once and for all outgrow our obsolete ideas about heredity. Genes don't code for traits. They synthesize proteins. And single proteins can do incredibly different things, depending on where and when they're produced . . .We have no gambling gene, no intelligence gene, no gene for language or walking upright.'" Later, Powers explains, "A single gene defect can knock out a complex behavior. But that does not mean complex behaviors derive from a single gene. One bad allele can cause depression. But a few good ones don't necessarily cause bliss." It is the nature vs nurture debate, and Powers concludes that the scientific consensus, "if any, is vague. Most talking heads ...concede that people's bedrock emotional skills vary as greatly as their skills in math. For proof, witness the chaos of this public argument [about whether there is a gene for bliss]."

And that brings me to another recent effort in the popular media to pronounce the role of genes in programming human behavior: the suggestion in a recent New York Times article by Nicholas Wade that there is a "god gene" that has programmed humans to believe in a god. Wade describes "a propensity to learn the religion of one’s community [that] became so firmly implanted in the human neural circuitry" as though it is a fixed biological component of human DNA. Wade is not alone in this suggestion, even on the op-ed pages of the New York Times. At the heart of this discussion is whether evolution operates on genes as advanced by Richard Dawkins in The Selfish Gene, or whether it operates alternatively or equally upon an entire organism, or on groups such as kin or whole communities as advanced by the sociobiologist E.O. Wilson. Wade, to his credit, acknowledges this debate, but never seriously muzzles the popular impression that there may actually be a "god gene." Nor does Wade acknowledge more penetrating research, such as Pascal Boyer's Religion Explained, which supports another explanation based on the human mind's adaptive embrace of animism and projection and that religion as commonly experienced across all human societies "is about the existence and causal powers of non-observable entities and agencies," what one commenter has called a "collection of fantasies about spirits." Not all of these spirits is capable of being called a "god."

About this most recent promotion of a genetic source for specific human behavior, Richard Powers could only say, "Witness the chaos of this public argument." As one letter to the editor that responded to Wade's polemic intoned:

"Many questions came to mind as I read “The Evolution of the God Gene.” What does it actually mean to postulate a god gene for religious belief? How does it work? What is the relationship between the organic gene and the human experience? Do we need one gene for a theist and another for an atheist, an agnostic or a polytheist?

"It is quite possible to accept evolution without resorting to an organic narrative to account for every specific human experience. Must there be a specific gene for playing poker or dancing the rumba? And if we believe in elves and witches, are corresponding genes required?"

Wednesday, November 4, 2009

Bert Hölldobler & E.O. Wilson, The Superorganism (2008)

Human (September 27 post), Mirroring People (September 18 post), and The First Word (August 31 post) all stress the social nature of the human species as something unique to homo sapiens. Marco Iaccoboni, as we saw in Mirroring People, believes that not enough weight is given to our social nature and too much consideration is given to our individuality. But what of other species? We know that other primates are social, although not to the extent of the human species. But there are other species who are even more socially organized than the human species. Meet the social insects --- bees, wasps, ants, termites --- who have established a diverse array of social communities, some of which have suppressed nearly all individuality.

Holldobler and Wilson's The Superorganism does not specifically address the big three areas of human inquiry -- the very large, the very small, and the human mind -- that I described in the August 31st post, but the book is devoted to that other question I mentioned: what is life? The subject-matter of The Superorganism is not entirely divorced from the books in the preceding posts. One of the links between each of the books reviewed in earlier posts is the subject of information and communication. The largest chapter of this beautiful book exhaustively summarizes what we know about communication within the species of the social insects --- not at the level of electrons and quarks and bosons that Seth Lloyd focused on --- but at the level of chemical compounds and the sensory capabilities of these insects: pheromones secreted to lay a trail for colony ants to follow leaders from the nest to food sources and back; odors of hydrocarbons that confirm the queen is present in the colony that shut down the reproductive capabilities of female workers so that only the queen becomes the source of eggs; odors of hydrocarbons that enable ants to distinguish members of their own colony from outsiders. There is also the suggestion, not inconsistent with Christine Keneally's statement in The First Word that human language is believed to have emerged from human motor skills, that insect communication may have emerged from the insect's motor skills.

But information is not the big idea in Superorganism. Information and communication among individual insects and competing groups of insects is just a significant piece of the evidence that supports the big idea in this book: multilevel natural selection. Since Richard Dawkins originally published The Selfish Gene in 1976, a debate has raged whether natural selection operates on genes, as advanced by Dawkins, or whether it operates on the individual organism (phenotype) --- the carrier of a collection of genes, or whether it operates on groups such as related kin, or more broadly communities or colonies. The advocates for each view were said to promote gene selection, individual selection, kin selection, or group selection respectively. Charles Darwin, because he lacked an understanding of Mendellian genetics, DNA and RNA, essentially propounded a view of individual selection, although he acknowledged, as Holldobler and Wilson note, that the altruistic behavior of the insect colony appeared to be an exception. Holldobler and Wilson join an emerging view that declares, "It's all of the above," and hence the nom "multilevel selection." The early advocates for multilevel selection, David Sloan Wilson and and Elliot Sober, refer to it as "a unified theory of natural selection that operates on a nested hierarchy of units." While declaring that "all selection is multilevel," Holldobler and Wilson acknowledge that the ultimate unit of evolution is the gene (or a group of alleles of interacting genes). Even Dawkins concedes, however, that the fate of a gene can be tied to the fate of other genes within the same phenotype, so the lines over the unit of natural selection have blurred as the debate ensues.

The unique case of the social insects posed a question for Darwin because he was bothered by the question of how the worker group of ants and other social insects could evolve if they were sterile and left no offspring. Holldobler and Wilson explain the principle of eusociality --- the care of offspring of a reproductive group by a worker group --- and the gem in this 500 page book is the presentation of a model, supported by some evidence, how the most advanced eusocial insects such as bees and leafcutter ants evolved their cohesive social organization of altruistic individuals over millions of years. While difficult for the lay person such as myself to follow on the first presentation, the theory is advanced by this sentence: "Altruism and eusociality are thus evidently born from the appearance of a phenotypically flexible eusocial allele (or ensemble of such alleles) in a progressive provisioning mother and between-group selection acting on emergent group traits, socially binding in nature and sufficiently powerful to overbalance the dissolutive effects of individual direct (within group) selection." Translation: at the gene selection level, traits are favored to enhance the survival of eggs or larvae by promoting social relationships that become strong enough (ie. that eliminate or minimize conflict within the group) to offset threats from competing social groups (other colonies or species) or the environment. This development was evolutionarily enabled because the alleles within the genes of the individual insects were flexible enough to activate this solution for survival. Finally, "when ecological and genetic factors advance a society to near the upper extreme of the superorganism continuum, subsequent selection may result in the complete loss of costly physiological structures involved in within-group competition" and "the capacity for 'selfishness' [becomes] insignificant because the underlying organs (for example, ovaries) important for within-group competition degenerate or become completely lost." For these unique groups of insects, the authors find that the colony is essentially an organism (phenotype), which they call a "superorganism." Borrowing a term from Dawkins, the authors conclude that the eusocial insect colony effectively becomes a target of natural selection because it is a coherent 'extended phenotype' of genes within colony members.

Importantly, the eusocial insects who form "superorganisms" are a very tiny percentage of the entire landscape of all species. They comprise only 15 species of more than 2600 species of insects. There is one species of vertebrates --- naked mole rats --- who fit this classification. However powerful the evidence for the superorganism is and the multilevel selection model, the truth remains that the critical unit of evolution is the gene. As the fictional character quoted in Richard Powers' Generosity says (see November 30 post), "Genes don't code for traits." Genes do code for chemical stimuli and sensory organs. This is not lost on Holldobler and Wilson who write, "Decision by decision, the insect responds to those stimuli to which its sensory and nervous systems are programmed to respond. These stimuli compose the highly filtered sensory world of the caste to which it belongs." And the science of evolutionary development, which posits that genes may not be expressed until a later developmental stage of life, undoubtedly has a role in explaining how insects "learn" altruistic behavior. Holldobler and Wilson provide evidence for this model as well in explaining that there are some species of female worker ants with ovaries in the nest that are simply suppressed by specific chemical recognition that a fertile egg-laying queen is in the nest, and when the queen dies, a worker ant's reproductive capabilities can be reactivated for the survival of the group.

If the reader of this book is, like me, learning about the social insects for the first time, there is a sense of awe in just how much we know about ants, bees, wasps, and termites. The quantum of information provided by the authors in support of their model, particularly about the ants, can be overwhelming at time. The authors' discussion of genetic social evolution and sociogenesis is delivered early in chapters 2 and 3, and the evidence follows for seven more chapters over 430 pages. After reaching the end of the book, go back and read chapters 2 and 3 again and the enormous amount of detailed evidence will come together.