Tuesday, May 21, 2019

Wishful Thinking Often Drives Science Activity

A recent article in The Atlantic is entitled "A Waste of 1000 Research Papers." The article is about how scientists wrote a thousand research papers trying to suggest that genes such as SLC6A4 were a partial cause of depression, one of the leading mental afflictions.  The article tells us, "But a new study—the biggest and most comprehensive of its kind yet—shows that this seemingly sturdy mountain of research is actually a house of cards, built on nonexistent foundations." 

Using data from large groups of volunteers -- between 62,000 and 443,000 people -- the scientific study attempted to find whether there was any evidence that any of the genes (such as SLC6A4 and 5-HTTLPR) linked to depression were more common in people who had depression. "We didn't find a smidge of evidence," says Matthew Keller, the scientist who led the study.  "How on Earth could we have spent 20 years and hundreds of millions of dollars studying pure noise?" asks Keller, suggesting that hundreds of millions of dollars had been spent trying to show a genetic correlation (between genes such as SLC6A4 and depression) that didn't actually exist. 

The article refers us to a blog post on the Keller study, one that comments on how scientists had tried to build up the gene 5-HTTLPR as a causal factor of depression. Below is a quote from the blog post by Scott Alexander:

"What bothers me isn’t just that people said 5-HTTLPR mattered and it didn’t. It’s that we built whole imaginary edifices, whole castles in the air on top of this idea of 5-HTTLPR mattering. We 'figured out' how 5-HTTLPR exerted its effects, what parts of the brain it was active in, what sorts of things it interacted with, how its effects were enhanced or suppressed by the effects of other imaginary depression genes. This isn’t just an explorer coming back from the Orient and claiming there are unicorns there. It’s the explorer describing the life cycle of unicorns, what unicorns eat, all the different subspecies of unicorn, which cuts of unicorn meat are tastiest, and a blow-by-blow account of a wrestling match between unicorns and Bigfoot."

How is it that so many scientists came up with an answer so wrong?  One reason is that they used sample sizes too small. The article in The Atlantic explains it like this:

"When geneticists finally gained the power to cost-efficiently analyze entire genomes, they realized that most disorders and diseases are influenced by thousands of genes, each of which has a tiny effect. To reliably detect these miniscule effects, you need to compare hundreds of thousands of volunteers. By contrast, the candidate-gene studies of the 2000s looked at an average of 345 people! They couldn’t possibly have found effects as large as they did, using samples as small as they had. Those results must have been flukes—mirages produced by a lack of statistical power. "

Is this type of problem limited to the study of genes? Not at all. The "lack of statistical power" problem (pretty much the same as the "too small sample sizes" problem) is rampant and epidemic in modern neuroscience. Today's neuroscientists very frequently produce studies with way-too-low statistical power, studies in which there is a very high chance of a false alarm, because too-small sample sizes were used. 

It is well known that at least 15 animals per study group should be used to get a moderately convincing result. But very often neuroscience studies will use only about 8 animals per study group. If you use only 8 animals per study group, there's a very high chance you'll get a false alarm, in which the result is due merely to chance variations rather than a real effect in nature.  In fact, in her post "Why Most Published Neuroscience Studies Are False," neuroscientist Kelly Zalocusky suggests that neuroscientists really should be using 31 animals per study group to get a not-very-strong statistical power of .5, and 60 animals per study group to get a fairly strong statistical power of .8.  


This is the same “too small sample size” problem (discussed here) that plagues very many or most neuroscience experiments involving animals. Neuroscientists have known about this problem for many years, but year after year they continue in their errant ways, foisting upon the public too-small-sample-size studies with low statistical power that don't prove anything because of a high chance of false alarms.  Such studies may claim to provide evidence that brains are producing thinking or storing memories, but the evidence is "junk science" stuff that does not stand up to critical scrutiny. 

So part of the explanation for why the "depression gene" scientists were so wrong is that they used too-small sample sizes, producing results with way-too-low statistical power. But there's another big reason why they were so wrong: their research activity was driven by wishful thinking.  Showing that genes drive behavior or mental states has always been one of the major items on the wish list of scientists who favor reductionist materialism.  

If you're an orthodox Darwinist, you're pretty much locked in to the idea that genes control everything.  Darwinists believe that a progression from ape-like ancestors to humans occurred solely because of a change in DNA caused by random mutations.  So if you think that some difference in DNA is the sole explanation for the difference between humans and apes,  you've pretty much boxed yourself into the silly idea that every difference between a human and an ape boils down to some gene difference or DNA difference.  I call the idea silly because the genes that make up DNA basically specify proteins, but no one has a coherent idea for how a protein could cause a mental state such as sadness, imagination,  spirituality or curiosity, nor a coherent idea of how a three-dimensional body plan could ever be stored in DNA (written in a "bare bones" language limiting it to only very low-level chemical information such as the amino acids that make up a polypeptide chain that is the beginning of a three-dimensional protein molecule). 

So the scientists wanted very much to believe there were "genes for depression," and genes for almost every other human mental characteristic; and they let their belief desires drive their research activities. 

Does this happen rarely in the world of science? No, it happens all the time. Very much of modern scientific activity is driven by wishful thinking. It is easy to come up with examples that remind us of this "depression genes" misadventure:

  • Countless “low statistical power” neuroscience papers have been written trying to suggest that LTP has something to do with memory, an idea which makes no sense given that LTP is an artificially produced effect produced by high-frequency stimulation, and given that LTP typically lasts only hours or days, in contrast to human memories that can persist for 50 years.
  • Countless “low statistical power” neuroscience papers have been written trying to suggest that synapses or dendritic spines are involved in memory storage, an idea which makes no sense given that synapses and dendritic spines are made up of proteins with lifetimes of only a few weeks or less, and that neither synapses nor dendritic spines last for even a tenth of the time that humans can remember things (50 years or more).
  • Countless “low statistical power” brain imaging studies have tried to show neural correlates of thinking or recall, but they typically show that such activities do not cause more than a 1% change in signal strength, consistent with random variations that we would see even if brains do not produce thinking or memory recall.
  • Having a desire to reconcile the mutually incompatible theories of quantum mechanics and general relativity, physicists wrote thousands of papers filled with ornate speculations about something called string theory, a theory for which no evidence has ever been produced.
  • Faced with biological organisms having functionally complex systems far more complex than any found in the most complex human inventions, and wishing fervently to avoid any hypothesis of design, scientists engaged in countless speculations about how such innovations might have been produced by random mutations of genomes, ignoring not merely the mathematical improbability of such "miracle of luck" events happening so many times, but also the fact that genomes do not specify body plans (contrary to the "DNA is a blueprint for your body" myth advanced to support such speculations).  
  • Faced with an undesired case of very strong fine-tuning involving the Higgs boson or Higgs field, scientists wrote more than 1000 papers speculating about a theory called supersymmetry which tries to explain away this fine-tuning; but the theory has failed all experimental tests at the Large Hadron Collider.  Many of the same scientists want many billions more for the construction of a new and more powerful particle collider, so that their fervent wishes on this matter can be fulfilled. 
  • Faced with an undesired result that the universe's expansion rate at the time of the Big Bang was apparently fine-tuned to more than 1 part in 1,000,000,000,000,000,000,000, scientists wrote more than a thousand speculative “cosmic inflation” cosmology papers trying to explain away this thing they didn't want to believe in, by imagining a never-observed instant in which the universe expanded at an exponential rate (with the speculations often veering into multiverse speculations about other unseen universes). 
  • According to this paper, scientists have written some 15,000 papers on the topic of "neural coding," something that scientists want to believe in because they want to believe the brain is like a computer (which uses coding).  But there is not any real evidence that the brain uses any type of coding other than the genetic code used by all cells, and no one has been able to discover any neural code used for either transmitting information in the brain or storing information in the brain.  Referring to spikes in brain electricity, this paper concludes "the view that spikes are messages is generally not tenable," contrary to the speculations of thousands of neuroscience papers. 
  • Scientists have had no luck in trying to create a living thing in experiments simulating the early Earth, and have failed to create even a single protein molecule in such experiments. But because scientists really, really wish to find extraterrestrial life somewhere (to prove to themselves that the origin of life is easy to naturally occur), scientists want billions of dollars for a long-shot ice-drilling space mission looking for life on Jupiter's moon Europa.
  • When the Large Hadron Collider produced some results that might have been preliminary signs of some new particle, physicists wrote more than 500 papers speculating about the interesting new particle they wanted to believe in, only to find the new particle was a false alarm. 
  • Scientists ran many very expensive experiments attempting to look for dark matter, something that has never been observed, but which scientists devoutly hoped to find, largely to prove to themselves that their knowledge of large-scale cosmic structure is not so small. 

Quite a few of these cases seem to be "imaginary edifices" in which the main controlling factor is what a scientist wants to believe or does not want to believe. 


Europa mission
NASA visual of a long-shot mission to look for life on Europa

The article in The Atlantic states the following, painting a portrait of a science world with very serious problems: 

“ 'We’re told that science self-corrects, but what the candidate gene literature demonstrates is that it often self-corrects very slowly, and very wastefully, even when the writing has been on the wall for a very long time,' Munafo adds. Many fields of science, from psychology to cancer biology, have been dealing with similar problems: Entire lines of research may be based on faulty results. The reasons for this so-called “reproducibility crisis” are manifold. Sometimes, researchers futz with their data until they get something interesting, or retrofit their questions to match their answers. Other times, they selectively publish positive results while sweeping negative ones under the rug, creating a false impression of building evidence."
In the world of science academia, bad ideas arise, and often hang around way too long, even after the evidence has turned against such ideas, because what is really driving things is what scientists want to believe or do not want to believe.  Wishful thinking is in the driver's seat, and the result of that is quite a few houses of cards, quite a few castles in the air, quite a few imaginary edifices that are often sold as "science knowledge."  

1 comment:

  1. I suspect that powerful motives for what you are exposing include money, prestige and power.

    ReplyDelete