Skeptifem: Whining about Evolutionary Psychology

People pointed out to Jesse Bering that his study in evolutionary psychology didn’t prove about rape what he was trying to test; so instead of admitting that it missed the mark, he whined about how ethics committees wouldn’t pass the kind of experiment that would prove it. So? It’s not ethical to design an experiment that doesn’t prove something and then say that it does. Skeptifem has a good discussion.
 
Even the most piss-poor studies with questionable conclusions are reported in the popular literature, repeated in magazines, and end up in Reader’s Digest and soak into the “popular wisdom,” where they taint attitudes towards women for generations.

Absence of evidence?

You’ll sometimes hear, “Absence of evidence is not evidence of absence.”

Absence of evidence is evidence of absence—of unicorns, for example. It’s just not proof of absence. On the other hand, millennia of absence of evidence is a strong argument for probability of absence, or non-existence if you prefer.

Someone suggested that the response to that is, “A claim that is put forward without evidence can be reliably dismissed unless and until evidence is provided.”

How can you tell it’s pseudoscience

Apart from the “motorized goalposts” that one person mentioned, Pharyngula commenter a_ray_in-dilbert_space had a pretty good idea. In science, the explanation gets clearer.

The problem with most pseudoscientific endeavors is that the problem does not converge. Mechanisms get more and more complicated to account for negative results while preserving the gist of the original proposal. This is a dead sign that it ain’t science.

Dead giveaway, I guess.

Papers on Homo floresiensis

Out of curiosity, I looked up the research papers on Homo floresiensis.

• Homo floresiensis: a cladistic analysis (original research)
  Journal of Human Evolution, Volume 57, Issue 5, November 2009, Pages 623-639
  D. Argue, M.J. Morwood, T. Sutikna, Jatmiko, E.W. Saptomo
• Homo floresiensis and the evolution of the hominin shoulder (original research)
  Journal of Human Evolution, Volume 53, Issue 6, December 2007, Pages 718-731
  Susan G. Larson, William L. Jungers, Michael J. Morwood, Thomas Sutikna, Jatmiko, E. Wahyu Saptomo, Rokus Awe Due, Tony Djubiantono
• Liang Bua Homo floresiensis mandibles and mandibular teeth: a contribution to the comparative morphology of a new hominin species (original research)
  Journal of Human Evolution, Volume 57, Issue 5, November 2009, Pages 571-596
  Peter Brown, Tomoko Maeda
• Body size and its consequences: Allometry and the lower limb length of Liang Bua 1 (Homo floresiensis) (original research)
  Journal of Human Evolution, Volume 57, Issue 3, September 2009, Pages 223-228
  Trenton W. Holliday, Robert G. Franciscus
• Descriptions of the lower limb skeleton of Homo floresiensis (original research)
  Journal of Human Evolution, Volume 57, Issue 5, November 2009, Pages 538-554
  W.L. Jungers, S.G. Larson, W. Harcourt-Smith, M.J. Morwood, T. Sutikna, Rokhus Due Awe, T. Djubiantono
• Descriptions of the upper limb skeleton of Homo floresiensis (original research)
  Journal of Human Evolution, Volume 57, Issue 5, November 2009, Pages 555-570
  S.G. Larson, W.L. Jungers, M.W. Tocheri, C.M. Orr, M.J. Morwood, T. Sutikna, Rokhus Due Awe, T. Djubiantono
• Geochronology of cave deposits at Liang Bua and of adjacent river terraces in the Wae Racang valley, western Flores, Indonesia: a synthesis of age estimates for the type locality of Homo floresiensis (original research)
  Journal of Human Evolution, Volume 57, Issue 5, November 2009, Pages 484-502
  R.G. Roberts, K.E. Westaway, J.-x. Zhao, C.S.M. Turney, M.I. Bird, W.J. Rink, L.K. Fifield
• A Reply to Trueman’s “A new cladistic analysis of Homo floresiensis.”
  Journal of Human Evolution, Volume 59, Issue 2, August 2010, Pages 227-230
  Debbie Argue, Mike Morwood, Thomas Sutikna, Jatmiko, E. Wahyu Saptomo
• A new cladistic analysis of Homo floresiensis
  Journal of Human Evolution, Volume 59, Issue 2, August 2010, Pages 223-226
  John W.H. Trueman
• Homo floresiensis: Microcephalic, pygmoid, Australopithecus, or Homo? (original research)
  Journal of Human Evolution, Volume 51, Issue 4, October 2006, Pages 360-374
  Debbie Argue, Denise Donlon, Colin Groves, Richard Wright
• The size of scalable brain components in the human evolutionary lineage: With a comment on the paradox of Homo floresiensis Original Research Article
  HOMO – Journal of Comparative Human Biology, Volume 58, Issue 1, 26 March 2007, Pages 1-12
  G.C. Conroy, R.J. Smith
• Homo floresiensis and the late Pleistocene environments of eastern Indonesia: defining the nature of the relationship
  Quaternary Science Reviews, Volume 28, Issues 25-26, December 2009, Pages 2897-2912
  K.E. Westaway, M.J. Morwood, T. Sutikna, M.W. Moore, A.D. Rokus, G.D. van den Bergh, R.G. Roberts, E.W. Saptomo
• Status of new species hypothesis for the remains attributed to Homo floresiensis
  HOMO – Journal of Comparative Human Biology, Volume 61, Issue 3, June 2010, Page 215
  P.J. Obendorf, B.J. Kefford, C.E. Oxnard
• Dynamic similarity predicts gait patterns for Homo floresiensis and the Laetoli footprints
  Journal of Biomechanics, Volume 40, Supplement 2, 2007, Page S40
  Christopher L Vaughan, Maria B Blaszczyk
• Cladistic analysis of early Homo crania from Swartkrans and Sterkfontein, South Africa
  Journal of Human Evolution, Volume 54, Issue 5, May 2008, Pages 684-704
  Heather F. Smith, Frederick E. Grine
• L’architecture de l’épaule au sein du genre Homo : nouvelles interprétations
  L’Anthropologie, Volume 114, Issue 3, June-August 2010, Pages 354-369
  Jean-Luc Voisin
• Preface: research at Liang Bua, Flores, Indonesia
  Journal of Human Evolution, Volume 57, Issue 5, November 2009, Pages 437-449
  M.J. Morwood, T. Sutikna, E.W. Saptomo, Jatmiko, D.R. Hobbs, K.E. Westaway
• Conclusions: implications of the Liang Bua excavations for hominin evolution and biogeography (original research)
  Journal of Human Evolution, Volume 57, Issue 5, November 2009, Pages 640-648
  M.J. Morwood, W.L. Jungers
• Size, shape, and asymmetry in fossil hominins: the status of the LB1 cranium based on 3D morphometric analyses Original Research Article
  Journal of Human Evolution, Volume 57, Issue 5, November 2009, Pages 608-622
  Karen L. Baab, Kieran P. McNulty

There are more but that’s where I ran out of time and energy.

Book: A New Human

I just recently bought A New Human: The Startling Discovery and Strange Story of the “Hobbits” of Flores, Indonesia.

The narrative voice is that of Mike Morwood, the principal Australian investigator in the discovery of Homo floresiensis. The cover design indicates that Penny Van Oosterzee did the bulk of the writing. The story certainly emphasizes that research is an intensely human and collaborative effort, recruiting large teams of researchers with various areas of expertise. The book is fascinating, especially all the techniques used to accurately date the findings. I learned something about techniques for nailing down accurate dates, about island biogeography, and about the probable origins of H. floresiensis: a small-bodied transitional form between Australopithecus and Homo.

Some minor details aren’t clear, e.g. which specimen or person is which in a picture. And I would have liked a medium-scale map of Flores and its surrounding islands. We go from small scale, where Lombok and Komodo are nameless blobs, to large scale, showing only a fraction of the island. A map showing the tectonic plates and subduction zones in Indonesia would have been nice, too. And there’s no index!  However, the story is engrossing and there is a list for further reading.

Why trust the theory of evolution?

Science is about what you can test and not disprove. Three hundred years ago European scientists started with the assumption that the Bible was a historical record and that the biblical flood was a real event. It took about one hundred years of gathering evidence to prove that one single flood could not be the explanation and that glaciers had caused many of the features formerly ascribed to a giant flood and another hundred to correlate geographical features into a coherent history.

It took about two hundred years, from the 1600s to the 1800s, to demonstrate that animal species had died out or changed over time. At this point, it was a historic discipline, like political history, studying what had occurred in the past by the evidence that remained. Darwin’s and Wallace’s brilliant suggestion as to how that happened, in general, was rapidly accepted. As Darwin pointed out, if cave critters had been specially designed for caves, you’d expect to find the same perfect cave critters everywhere. Instead, cave critters in each ecosystem are modified versions of the organisms that live above the ground in that area, just as if they had descended from something that fell or wandered into the cave.

However, at that time genes and chromosomes were unknown. Neither Darwin nor his colleagues knew how a special trait could become more common and not blend back into the average. About that time, Gregor Mendel, breeding peas for years and recording the results, worked out the math of simple dominant inheritance with one gene or two genes; but he published in an obscure Austrian journal. His work did not reach the larger scientific community until almost one hundred years later. In the 1930s, when the genetic theory was added to the theories of natural and sexual selection, the theory of evolution became robust.

Quite a bit of mathematical analysis and prediction, by R.A. Fisher and others, made testable cases for evolution, and evolution passed them. For example, why do most species have equal numbers of both sexes? What should the ratio be when resources are temporarily plentiful? What if resources are restricted but it’s easy to find a mate?  But what carried the genetic information was still a mystery. Was it DNA or a protein, perhaps albumin? In the late 1930s, DNA was proven to be the key to inheritance.

The giant chromosomes in the salivary glands of fruit flies let us see something of their structure. Since then, we have learned to trace the evolution and ancestry of individual genes and chromosomes. For example, chimpanzees have one more chromosome than we do: but one of our chromosomes matches up with two of theirs; and there’s even an extra centromere in our chromosome, vestige of its former existence as a separate unit. It’s pretty obvious that we diverged from chimpanzees before the chromosomes fused.

Molecular evolution was developed in the 1960s; that’s where we trace the changes in a single important molocule through various species, noting the changes along the way. It’s the equivalent of literary research, where a single change in a manuscript of the Bible, e.g. the change from “young woman” to “virgin,” is used to track what further manuscripts were copied from the new error clarification.

The “family trees” made from comparing organisms agree with the evidence of fossils. Hypotheses about the environments and conditions where significant evolution might have occurred suggest places for scientists to look for fossils. That’s how the famous Tiktaalik transitional fossil was found in the sediments of Devonian freshwater swamps. And new discoveries occur all the time. Surely you know of the complete set of transitional mammals, discovered in the 1990s, from a hoofed land-dweller to a swimmer to whales.

In the past decade, evolution has been observed in the laboratory with the development of completely novel traits in bacteria. Evolution has been observed in the wild with two new species of flower developing in the U.S. Northwest in the 1940s. It has been observed in the development of a new species of mosquito that inhabits the London subway system, in a mere 150 years. On a similar time scale, the hawthorn gall midge produced a variety that prefers apples and does not mate with its ancestral strain. Other examples abound.

It only strengthens the case for evolution when the family trees drawn by research into molecular evolution match those drawn on the basis of physiology and fossils.

Then look into ERVs: endogenous retroviruses. Viruses can and do read themselves into our genes. Those, too, are inherited and can also be traced in family trees. Many of them are inactive; however, mutations sometimes reactivate them by chance. For example, the ERV for mouse mammary tumor gives women a higher chance of developing breast cancer.

With evolution, with science, it’s all about the facts.

Credulous documentary rubbished in review

This Media Watch video chastises the Australian Broadcasting Corp. for showing Lee Berger’s documentary about a variety of small humans on the island of Palau in Micronesia without noting that his research had been debunked more than a year previously.

For more info and commentary, see Anthropology.net, “Berger can’t get a break.”

Russet feathers!

Before birds, there were feathers–naturally enough. Feathers, like hair, no doubt provided insulation and were grown by dinosaurs. Indeed, reptilian scutes when properly treated with a mild acid can fall apart into a feather-like structure. I suspect that the first advantage that they imparted was warmth for a small animal. But camouflage probably came second. When you have temporary structure like feathers, you can change color with the seasons. The color can vary by combining red and black pigments. It can pulse on and off as the feather grows or in different parts of the body to form pigmented bands. I have seen dinosaur-bird fossils where the bands in the feathers call to mind the wings and tail of a hawk.

But that’s just a hypothesis! Scientists have shaved a pigmented fossil into microscopic bits to identify the pigment granules and classify their color type: black or Irish-setter red. They applied their findings to the reconstructed fossil to see its color pattern. Behold!

True colors

The lovely illustration is by Chuang Zhao and Lida Xing

GrrlScientist has a fine, detailed description and lots of images of how the research on Sinosauropteryx was done with scanning electron microscopy.

It’s easy to create lines, cross-hatching, or speckles when two such color pulses combine into a moire pattern.