May 09 2019

Source Credibility

How much of an influence does the source of information have on our reactions to that information? Not surprisingly, it has a significant effect. A new study supports this conclusion, but I think the implications are far more narrow than the reporting suggests.

In the study subjects were first given a generally positive attitude toward a character named Kevin. They were then told something disturbing about Kevin, that he beat his wife. However, one group was told this information came from official police reports. The other was told it came from a friend of Kevin’s ex-girlfriend. The new information had a much greater effect on attitudes when it came from a credible source than a dubious one. This was true even if the information first created a negative impression of Kevin, and then the subjects were later told the source of the information. They quickly corrected their opinion with the new information.

I find none of this surprising given prior psychological research. When it comes to beliefs about which we are largely emotionally neutral (like our attitudes toward a fictional character in a study) we tend to naturally follow a Bayesian approach – we update our conclusions as new information comes in. We also have a desire to be correct, all things being equal, and therefore would reasonably consider the source of information. The study results may also be reflecting a small confirmation bias. If subjects already believe Kevin is a good guy, they would be biased against changing this conclusion unless the new information warranted it. So a rumor from a friend of an ex-girlfriend, which we can easily rationalize away as having a grudge, is not enough. It’s hard to argue with official police reports, however.

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May 07 2019

Why Prior Probability Matters

Back in the early days of my skeptical career I attended a skeptical conference hosted by CSI (then CSICOP). One panel stuck out, and I still remember some details more than two decades later. This was a panel on extrasensory perception (ESP). The proponent on the panel argued that the research showing that ESP is real shows as much of an effect as the research showing that aspirin prevents strokes. Therefore if we accept one, we should accept the other. Even my nascent skepticism was able to detect that this argument did not hold water, but now I understand why in far greater detail. There are many problems with the claim (such as the quality of the research and the overall pattern of results) but I want to focus on one – the role of prior probability.

This is often a sticking point, even among mainstream scientists and clinicians, I think because of the inherent human lack of intuition for statistics. Most scientists are not statisticians, and are prone to making subtle but important statistical mistakes if they don’t have proper consultation when doing their research. In fact, there is an entire movement within mainstream medicine that, in my opinion, is the result of large scale naivete regarding statistics – evidence-based medicine (EBM).

EBM focuses on clinical research to answer questions about whether or not a treatment works. Conceptually EBM explicitly does not consider prior probability – it only looks at the results of clinical trials directly asking the question of whether or not the treatment is effective. While this may seem to make sense, it really doesn’t.

Let me explain.

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May 06 2019

Detecting Lies in the Brain

It’s fairly common knowledge at this point that the polygraph test for detecting who is lying is not reliable enough to be used practically. Here is a good summary by the American Psychological Association (APA). The bottom line is that the entire idea of a lie-detector is problematic for various reasons. First, the underlying premises have not really emerged from psychological research, and has not been validated by research. The idea is that people will display physiological signs of stress when they are making an effort to be deceptive, or when confronted with incriminating information. However, the relationship between physiological signs and mental stress is too complex to develop any test. There is no universal feature of lying that can be detected.

The polygraph uses two basic techniques. The first is the control question test (CQT) – you ask questions of the person being examined, control questions that do not relate to the crime in question, and relevant questions related to the crime. The idea is that they will react more to the relevant than the control questions. The other method, the guilty knowledge test (GKT) is similar – mentioning random items along with one directly related to the crime may reveal guilty knowledge that only the perpetrator should know.

The idea sounds compelling, and it does work in that using these techniques results in a slight statistical advantage in determining who is lying and who isn’t. However, a small statistical advantage is all but worthless in practical application. There are too many false positives and false negatives to be useful. For any individual suspect, at the end of the test you still don’t know if they are lying or not.

Part of the problem is that people are complex and variable. Not everyone responds the same way to stress, or to the situations provoked in the testing. But the problem is worsened by the existence of effective mental countermeasures. There are two basic countermeasures that have been shown to be effective – lowering further the statistical effect of the polygraph. The first is to assign mental significance to control items or questions, thereby reacting similarly to the control and the relevant items. The second is to create mental distance to all the items, including the relevant ones. Focus on something else – the sound of the words, their precise dictionary meaning, or imagine a famous character saying them. If the statements are in writing, you can focus on the color of the ink, the font, or other superficial aspects.

These countermeasure work. They successfully blur any difference between control and relevant items.

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May 03 2019

Organic Solar Cell Breakthrough

It’s interesting to try to envision the energy infrastructure 50 and 100 years in the future. Which technologies will prove the most cost and carbon effective? Of course, this can be a bit of a self-fulfilling prophesy – the technologies we think will work will be the ones we invest in and develop. This is why I think we should hedge our bets by developing every viable option. Can nuclear fission be made cost-effective? Will fusion ever be practical? How efficient can solar get, and what grid storage options will work best?

Having said that, I do think it’s pretty clear that solar energy will play an increasing role in our energy infrastructure. As of 2018 solar represents only 1.6% of energy production in the US, but is growing rapidly. Most solar panels in use today are silicon based. They are getting cheaper and more efficient, and have already crossed the line to cost-effectiveness in most areas, and within a decade should be cost effective everywhere.

Solar, of course, is an intermittent energy source, not on-demand. Right now, with such little penetration, you can basically use the grid as your battery – put energy into the grid when you produce more than you use, and take energy from the grid when you need more than you produce. This is why net metering laws are so important – making sure that customers with solar get full credit for the excess energy they produce. This strategy will work until we get to about 20% penetration. Then storage will be necessary to get to higher levels of solar in the mix.

Storage can be individual, like having a power wall in your home. Or it can be massive grid storage run by the power companies themselves. Likely we will have both in the future. Exactly what we will do for storage, in my opinion, is one of the open technological questions.

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May 02 2019

Pilots Reporting UFOs

The Navy recently drafted new policies for how its pilots and other personnel should report any encounters with “unexplained aerial phenomena” – more commonly known as unidentified flying objects, or UFOs. They say this is in response to an uptick in pilots reporting such encounters and requesting a formal way to report them.

The reporting on this topic ironically reveals the underlying problem in the first place – there is a stigma attached to the reporting of UFOs because of their cultural association with claims that they are (or may be) alien in origin. People mentally equate UFO with flying saucer (a colloquial term for any alien spacecraft of any shape).

Even sober takes on this topic focus heavily on the probability that such sightings are an alien phenomenon. Tyler Cowen does touch on many possible interpretations of UFO sightings, but spends the bulk of his commentary exploring how probable it is that aliens are visiting. He concludes it is not likely, but the chance is non-zero and deserves to be explored.

While I basically agree, I still think the framing is problematic. Essentially we are taking a phenomenon that likely has multiple causes, some known and some unknown, and focusing most of our attention on what is probably the least likely unknown possible cause. This would be like defining a new clinical syndrome by the least likely possible disease that could be causing it. This constrains our thinking, and in this case creates an unfair stigma. It also fuels conspiracy theories and wild speculation by the public. An further, it has resulted in paying too little attention to a phenomenon that may have practical real-world implications.

Returning to the medical analogy – there are fake diseases in the popular culture used to explain very real symptoms. For example, some people with chronic skin symptoms think they have a bizarre form a parasitosis. They clearly don’t, but that should not cause us to be dismissive of everyone with the same symptoms, or to ignore the search for underlying real causes.

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Apr 30 2019

Skeptic vs Denier

The skeptic vs denier debate won’t go away. I fear the issue is far too nuanced for a broad popular consensus. But that should not prevent a consensus among science communicators, who should have a technical understanding of terminology.

A recent editorial in Forbes illustrates the problem. The author, Brian Brettschneider, makes a recommendation for when to use which term, which sounds superficially reasonable but I think he misses the essence of the issue. His solution is this – if you have an advanced degree in climate science and you have doubts about the mainstream view, then you are given the benefit of the doubt and should be referred to as a skeptic. If you do not have a formal degree in climate science, then you have no business going against the consensus of mainstream scientific opinion and you should not be given the benefit of the doubt, and are hence a denier.

This is not a bad rule of thumb as an initial assumption, but does not work as a technical distinction.

First let me say that I agree with the underlying premise. It is not a logical fallacy (argument from authority) to defer to a strong consensus of legitimate expert opinion if you yourself lack appropriate expertise. Deference should be the default position, and your best bet is to understand what that consensus is, how strong is it, and what evidence supports it. Further, if there appears to be any controversy then – who is it, exactly, who does not accept the mainstream consensus, what is their expertise, what are their criticisms, and what is the mainstream response? More importantly – how big is the minority opinion within the expert community.

This is where a bit of judgment comes in, and there is simply no way of avoiding it. There is no simple algorithm to tell you what to believe, but there are some useful rules. Obviously, the stronger the consensus, the more it is reasonable to defer to it. There is always going to be a 1-2% minority opinion on almost any scientific conclusion, that is not sufficient reason to doubt the consensus. But you also need to find out what, exactly the consensus is, and what is just a working hypothesis. Any complex theory will have multiple parts, and it’s not all a package deal.

For example, let’s take evolutionary theory. There is almost unanimous consensus (>98%) among experts that evolution happened, that all living things on Earth are related through a nestled hierarchy of common descent. Further, the evidence for that conclusion is overwhelming and cannot be reasonably denied. Further still, there is no alternative scientific hypothesis that can account for that mountain of evidence (note the word “scientific” in that sentence). But the same is not true of all aspects of evolutionary theory. That natural selection is a main driving force of evolutionary change is also well established, but there is still legitimate debate about the role and magnitude of other factors, such as genetic drift. When we drill down to details about which species evolved into which other species and when, drawing a precise tree of evolutionary relationships, then there is considerable debate and much that is unknown.

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Apr 29 2019

Phosphorene Nanoribbons

As technology advances we find better and better ways to use existing materials. However, material science has the potential to introduce new materials to the equation, changing the game. It’s ironic that news about new materials tends to get relatively little attention in the media, but perhaps has the greatest potential to change our world.

That is exactly what I felt when I read this news about a production process to produce phosphorene nanoribbons. Sound boring, right? That’s why the popular reporting doesn’t even mention any of those things in the headline, but rather goes with the potential applications – We accidentally created a new wonder material that could revolutionise batteries and electronics.

As an aside, I don’t like the common narrative that something was discovered, “by accident.” The unspoken premise is that science is mostly looking directly for a specific effect or application. That is only a small subset of science, called translational research, where we are taking a discovery and looking to translate it into specific applications. However, the majority of research is just trying to figure out how stuff works. Often the findings of research are unexpected, and lead to new questions, and open up new possible applications. This is not “accidental” – it’s just part of the process. But the media loves that meme.

In any case, the actual paper, published in Nature, is not even about discovering the new material itself (which was discovered 5 years ago) but rather a process for reliably manufacturing large quantities of it with controllable properties. If you know anything about material science, that’s a huge deal, because most new wonder materials can’t get out of the lab because there is no way to mass produce them.

Phosphorene nanoribbons are “tagliatelle-like ribbons one single atom thick and only 100 or so atoms across, but up to 100,000 atoms long.” (Love the pasta reference.) They are made of phosphorous, which is an abundant element. Many 1 or 2-dimensional nanomaterials have been in the news over the last decade, most famously carbon nanosheets and nanofibers – 1 atom thick layers of carbon atoms which can be rolled into fibers. This class of materials is exciting because they have unique properties, such as strength (for their size), and electrical properties that can make them either incredible conductors or insulators, with low energy and heat dissipation needs.

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Apr 23 2019

Behind the Curve – Flat Earth Exposed

I finally watched Behind The Curve, a documentary about the Flat Earth movement. It is a powerful documentary which provides important insights into this fascinating phenomenon. If you haven’t seen it yet, I highly recommend it.

For me the most interesting moments were those when the Flat Earth believers the film focuses on show a flash of insight. They never quite get there, but they have all the pieces in front of them, they see them, they see their significance, but can’t quite make the final emotional connection.

The other aspects that I found most interesting were those that provided generic insight into how ideological movements work. There is some basic and universal human psychology going on, and in some ways it’s a mirror to any group of humans, including skeptics.

I also was especially interested in the question, directly addressed by the film, of how best to approach Flat Earthers and the entire movement. What is our responsibility here as science communicators, and what is our best strategy?

Some reviews have focused on those moments when Flat Earthers did experiments to test their theory, and were wrong. These are, of course, delicious. For example, one group purchased a ring laser gyroscope, a $20k device that can very sensitively measure movement. They say straight up, and correctly, that if the earth is a globe and it rotates once every 24 hours, then there should be a 15 degree drift in the gyroscope every hour. That is their experimental hypothesis.

So – they set up the device and…it measures a 15 degree drift every hour. QED – the Earth is a rotating globe.

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Apr 22 2019

Partially Reviving Dead Pig Brains

I turns out they were only “mostly dead.” Well, it depends on your definition of death.

This is an interesting study that has been widely reported, with a surprisingly small amount of hype. The New York Times writes:

‘Partly Alive’: Scientists Revive Cells in Brains From Dead Pigs
In a study that upends assumptions about brain death, researchers brought some cells back to life — or something like it.

All the reporting I have seen so far has appropriate caveats, but they are really trying hard to maximize the sensational aspects of this study. I actually wrote about this study one year ago when the data was first presented. Now it has been published, so there is another round of reporting (which interestingly ignores the prior reporting).

The quick version is that Yale neuroscientists collected decapitated pig brains four hours after death and then tried to keep the brain cells alive in order to see what would happen. It’s actually a great real-life Frankenstein type experiment, a fact not missed by some outlets. Here is what they did: Continue Reading »

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Apr 18 2019

Should We Ban Plastic Bags

Probably – but it’s complicated.

That is often the unfortunate answer when we ask big questions about how best to manage the world. We want to feel good about ourselves for being good citizens, or at least champion clear policies that are objectively better and effective at achieving our goals. Reality rarely accommodates these desires.

Part of the problem is that there are over 7 billion people on the planet and growing, and our industrial civilization uses a lot of resources. So anything that millions or billions of people do is likely to have an impact. Because of this there may simply be no perfect option.

But further, the available options tend to have trade-offs. Therefore if you ask, which option is better, the answer often is – it depends. It depends on how you ask and how you answer the question. Defining the problem is often easier – the solution, not so much.

The problem here is clear – single use plastic products do not biodegrade. They survive in the environment for about 400 years. They will break down into microplastics, but these stay in the environment and can still cause problems. A recent study found microplastics in remote regions of the Pyrenees. They are basically everywhere. Plastics clog our oceans and increasingly animals are turning up dead bloated with plastic waste.

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