Archive for May, 2020

May 29 2020

The Learning Styles Myth

I have written previously about the fact that the scientific evidence does not support the notion that different people have different inherent learning styles. Despite this fact, the concept remains popular, not only in popular culture but among educators. For fun a took the learning style self test at It was complete nonsense. I felt my answer to all the forced-choice questions was “it depends.” In the end I scored 35% visual, 35% auditory, and 30% kinesthetic, from which the site concluded I was a visual-auditory learner.

Clearly we need to do a better job of getting the word out there – forget learning styles, it’s a dead end. The Yale Poorvu Center for Teaching and Learning has done a nice job of summarizing why learning styles is a myth, and makes a strong case for why the concept is counterproductive.

The idea is that individual people learn better if the material is presented in a style, format, or context that fits best with their preferences. The idea is appealing because, first, everyone likes to think about themselves and have something to identify with. But also it gives educators the feeling that they can get an edge by applying a simple scheme to their teaching. I also frequently find it is a convenient excuse for lack of engagement with material.

There are countless schemes for separating the world into a limited number of learning styles. Perhaps the most popular is visual, auditory, vs kinesthetic. But there are many, and the Yale site lists the most popular. They include things such as globalists vs. analysts, assimilators vs. accommodators, imaginative vs. analytic learners, non-committers vs. plungers. If you think this is all sounding like an exercise in false dichotomies, I agree.

Regardless of why people find the notion appealing, or which system you prefer, the bottom line is that the basic concept of learning styles is simply not supported by scientific evidence.

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May 28 2020

Confidence Drives Confirmation Bias

Published by under Neuroscience

Human thought processes are powerful but flawed, like a GPS system that uses broken algorithms to lead you to the wrong destination. Psychologists study these cognitive biases and heuristic patterns of thought to better understand these flaws and propose possible fixes to mitigate them. To a large degree, scientific skepticism is about exactly that – identifying and compensating for the flaws in human cognition.

Perhaps the mother of all cognitive biases is confirmation bias, the tendency to notice, accept, and remember information that confirms what we already believe (or perhaps want to believe), and to ignore, reject, or forget information that contradicts what we believe. Confirmation bias is an invisible force, constantly working in the background as we go about our day, gathering information and refining our models of reality. But unfortunately it does not lead us to accuracy or objective information. It drives us down the road of our own preexisting narratives.

One of the things that makes confirmation bias so powerful is that it gives us the illusion of knowledge, which falsely increases our confidence in our narratives. We think there is a ton of evidence to support our beliefs, and anyone who denies them is blind, ignorant, or foolish. But that evidence was selectively culled from a much larger set of evidence that may tell a very different story from the one we see. It’s like reading a book but making up your own story by only reading selective words, and stringing them together in a different narrative.

A new study adds more information to our understanding of confirmation bias. It not only confirms our selective processing of confirming information, it shows that confidence drives this process. So not only does confirmation bias lead to false confidence, that confidence then drives more confirmation bias in a self-reinforcing cycle.

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May 25 2020

Can We See Personality?

Published by under Neuroscience

Is someone’s basic personality type written on their face? This is an interesting question, that research has not definitively answered. A new study uses AI to add one more piece of information, suggesting that the answer is – maybe, sort of.

Let’s start with a technical definition of personality:

“Personality refers to individual differences in characteristic patterns of thinking, feeling and behaving.”

It is uncontroversial that different people have different personality traits, although there are different schemes for how to divide up all the different recognizable personality traits people might display. One of the more accepted schemes is OCEAN (the big five) – Openness, Conscientiousness, Extroversion, Agreeableness, and Neuroticism. This does not capture every aspect of one’s personality, nor the rich background of experience and culture that helps mold our behavior, but it does seem to capture something fundamental about how humans vary.

Far more controversial is whether or not there are different personality types, meaning a suite of personality traits that tend to go together. There are many tests based on the assumption that people can be sorted into a small number of different personality types, but none of them have established validity. The best evidence we have so far, in my opinion, does not support the notion of personality types in any meaningful way.

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May 22 2020

Storing Carbon to Mitigate Climate Change

Published by under Technology

Here is a tiny bit of good news on the climate change front: A new analysis finds that there is more than enough storage space globally to fit the carbon we would need to capture and store if we wish to meet our climate change goals. The found:

No more than 2700 Gt of storage resource is required under any scenario to meet the most ambitious climate change mitigation targets.

Meanwhile current estimates of global carbon storage capacity are around 10,000 Gt. This does not mean we will meet our targets, it only means that global carbon storage capacity will not be a limiting factor. It’s always fun to learn that something you didn’t even know was a problem turns out not to be a problem anyway. But let’s break this down a bit.

The study modeled climate change mitigation scenarios using different assumptions about reducing fossil fuel use, increasing renewable energy, electrifying the transportation sector, energy efficiency, and carbon capture. They ran 1,200 different scenarios through the simulation, and found that under any scenario the maximum amount of carbon storage that would be necessary to meet the goal of no more than 2 C warming is 2,700 Gt. How much storage we would actually need, however, varied considerably based upon the other details. Specifically, the faster we ramp up carbon capture and storage (CCS) the less storage space we will ultimately need. The longer we wait, the harder it will be, and the more we will need to make up for lost time with CCS.

Also, like many resources, space for CCS varies in terms of convenience and cost. The more space we need, the more we will have to rely upon the less and less efficient storage space. So the longer we delay climate mitigation, the harder it will get.

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May 21 2020

Localizing Executive Function

Published by under Neuroscience

Where in the brain is a specific ability located? This is a more complex question than it may at first seem, mainly because we first have to define each specific ability. Some are obvious, like the ability to voluntarily move your right hand. The motor strip in the cortex physically maps to the body, and it is relatively easy to correlate a specific part of the brain to weakness of any specific body part. But even something as simple as motor control has many layers – other parts of the brain that modify control, allowing for smooth coordinated movement, for example.

Arguably the most difficult functions to localize in the brain are the more abstract ones, like executive function. This is extremely challenging partly because we don’t really know what those functions are at their most fundamental level. We can learn what behaviors they allow, but how? What is actually happening in the brain when you make a decision, for example?

Some of these more abstract functions are also difficult to study because they may be bilateral, meaning that the same structure on both sides of the brain contribute to the function. Therefore a lesion taking out one side won’t necessarily cause any deficits. Motor control, by contrast, is unilateral, so one single lesion causes an obvious deficit. This is important because studying lesions is one major way neuroscientists localize brain function – wait for it to break and than see what doesn’t work. Historically such lesion studies have been the most important method for mapping the brain.

Today we have other methods, such as imaging the brain functioning (fMRI), mapping electrical activity with EEG, and even temporarily influencing brain function with electrical or magnetic stimulation. This data (the first two methods, anyway), however, is mostly correlational. It can still be powerful, but a lesion is helpful in confirming causation.

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May 19 2020

Low Accuracy in Online Symptom Checkers

A new study published in Australia evaluates the accuracy of 27 online symptom checkers, or diagnostic advisers. The results are pretty disappointing. They found:

The 27 diagnostic SCs listed the correct diagnosis first in 421 of 1170 SC vignette tests (36%; 95% CI, 31–42%), among the top three results in 606 tests (52%; 95% CI, 47–59%), and among the top ten results in 681 tests (58%; 95% CI, 53–65%). SCs using artificial intelligence algorithms listed the correct diagnosis first in 46% of tests (95% CI, 40–57%), compared with 32% (95% CI, 26–38%) for other SCs. The mean rate of first correct results for individual SCs ranged between 12% and 61%. The 19 triage SCs provided correct advice for 338 of 688 vignette tests (49%; 95% CI, 44–54%). Appropriate triage advice was more frequent for emergency care (63%; 95% CI, 52–71%) and urgent care vignette tests (56%; 95% CI, 52–75%) than for non‐urgent care (30%; 95% CI, 11–39%) and self‐care tests (40%; 95% CI, 26–49%).

More distressing than the fact they the first choice was correct only 36% of the time, is that the correct diagnosis was only in the top 10 only 58% of the time. I would honestly not expect the correct diagnosis to be in the #1 slot most of the time. For any list of symptoms there are a number of possibilities. If there are 3-4 likely diagnoses, listing the correct one first about a third of the time is reasonable. You could argue that the problem there is simply not ordering the top choices optimally.

But not getting the correct diagnosis in the top 10 is a completely different problem. This implies that the correct diagnosis was entirely missed 42% of the time.

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May 18 2020

No Benefit from Hydroxychloroquine for COVID-19

In March Trump tweeted: “HYDROXYCHLOROQUINE & AZITHROMYCIN, taken together, have a real chance to be one of the biggest game changers in the history of medicine. The FDA has moved mountains – Thank You!” He has continued to support this untested drug since, turning what should have been a minor footnote in the COVID-19 pandemic into a political controversy.

As evidence of putting politics above science, Dr. Rick Bright claims he was removed from his post simply for questioning the promotion of hydroxychloroquine:

Dr. Rick Bright was abruptly dismissed this week as the director of the Department of Health and Human Services’ Biomedical Advanced Research and Development Authority, or BARDA, and removed as the deputy assistant secretary for preparedness and response. He was given a narrower job at the National Institutes of Health.

In a scorching statement, Dr. Bright assailed the leadership at the health department, saying he was pressured to direct money toward hydroxychloroquine, one of several “potentially dangerous drugs promoted by those with political connections” and repeatedly described by the president as a potential “game changer” in the fight against the virus.

The Plandemic conspiracy theorists promoted hydroxychloroquine as a cure for the pandemic, suggesting the government (yes, the same one headed by Trump) was withholding it to make money off an eventual vaccine.

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May 15 2020

Stimulating the Visual Cortex

Published by under Neuroscience

For adults who had vision but then lose it due to eye disease or damage to the optic nerve, their visual cortex is still intact. It is deprived if input, but is theoretically capable of functioning normally to create images. The ultimate technological expression of this potential would be something like the visor of Geordi La Forge – a device that can see (even in frequencies and particles humans cannot normally see) and transfer that information to the visual cortex. Obviously we are a long way away from any such technology, but we have taken the first baby steps in that direction, including a recent study which makes one tiny advance (but more on that shortly).

Early research into this approach involved animals and simply tried to determine if the monkeys could “see” the stimulation. Often simple behaviors, like moving their eyes, were used to see if the stimulation was having any effect. Some of the research also comes from trying to map the visual cortex, not necessary allow the blind to see. This research has been encouraging, because it shows that the primary visual cortex is arranged in a way to reflect the images it sees (so-called retinal mapping). The neurons, in short, are like a bitmap of an image. So if you stimulated a circle of neurons in the primary visual cortex, subjects would see a circle.

Of course there is more to vision than the primary visual cortex. A lot of processing occurs in the nerves  and pathways carrying information to the cortex. After the basic image is formed it is then sent to higher visual cortical areas for further processing, so a two-dimensional image is given shape, shading, movement, distance, three-dimensionality, and ultimately meaning. But hopefully we wouldn’t need to worry about all that higher levels of processing because once the image is presented to the primary visual cortex, the rest should take care of itself.

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May 14 2020

It’s Time for Telehealth

Perhaps one of the positive outcomes of the pandemic is an acceleration of acceptance of telehealth and telementalhealth – treating patients online instead of in person. For example, we have been trying to institute telehealth where I work for years, but have met with roadblocks. Then, all of a sudden, we were able to do it. Our clinic manager estimates that we accomplished in three weeks what would have otherwise taken three years. I have been doing mostly telehealth visits for the last two months now. It’s not perfect, but for many patients it is an ideal option.

The advantages are pretty obvious. A regular visit involves driving into a clinic (which may be in a city, and involves fighting traffic and finding parking), then checking in, and sitting in the waiting room until finally called. Then the meeting happens with the physician. Afterwards you go to check out, and then have to drive home. Depending on the length of the drive, you may spend 2 hours or more total time for 10 minutes of face time with the physician for an uncomplicated follow up visit. Compare this to signing onto an app from the comfort and convenience of your home, having the 10 minute visit over video, then you are done. This also means you are not sitting in a waiting room with potentially sick individuals. Many patients also have a difficult time getting to the clinic. They have physical limitations, and may even require special transportation to get there.

You can even do a limited physical exam over video. Anything that is purely visual and doesn’t require physical contact can be examined. But many patients do not require a physical exam as part of their follow up – their original exam was normal and there is nothing to follow. I see many patients with migraines, for example. Once it has been established that their headaches are indeed migraines (the workup, including exam, for other causes is negative) there is no need for any further physical exam unless something changes. Continue Reading »

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May 12 2020

Do Facemasks Work?

The question of whether or not wearing a facemask “works” is incredibly complicated. It may not seem so at first, but let me list some of the specific questions contained in that broad question. We need to consider different kinds of masks – cloth, surgical, N95. We need to consider who is wearing the mask – someone known to be infected, someone who is well, and in what setting, out in public or in the presence of those known to be sick. We also need to operationally define “work.” We can measure reduction in the spread of the virus, in droplets, in aerosolized particles, and also in different conditions (breathing, coughing) and at different distances. We can measure deposition of virus on surfaces. We can also measure transmission of actual disease, both the chance of spreading and of catching specific illnesses. And of course, all of these questions need to be addressed with each specific infection, and so prior research may not apply perfectly to COVID-19. And further we need to compare the efficacy of wearing a mask to the real-work effectiveness of intending to use a mask.

It should not be surprising, therefore, that we do not have all the answers to these questions specifically for COVID-19. What we have are slices of research with different results and therefore you can look at the preliminary evidence we do have and come to different conclusions. The CDC and the WHO, in fact, have done this. Here is the CDC recommendation:

CDC recommends wearing cloth face coverings in public settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies), especially in areas of significant community-based transmission.

CDC also advises the use of simple cloth face coverings to slow the spread of the virus and help people who may have the virus and do not know it from transmitting it to others.  Cloth face coverings fashioned from household items or made at home from common materials at low cost can be used as an additional, voluntary public health measure.

Cloth face coverings should not be placed on young children under age 2, anyone who has trouble breathing, or is unconscious, incapacitated or otherwise unable to remove the mask without assistance.

The cloth face coverings recommended are not surgical masks or N-95 respirators.  Those are critical supplies that must continue to be reserved for healthcare workers and other medical first responders, as recommended by current CDC guidance.”

And here is the WHO:

If you are healthy, you only need to wear a mask if you are taking care of a person with COVID-19.

The WHO recommends masks for those who are symptomatic or known to have COVID-19, and those exposed to people who are sick, but not for the healthy out in public. The guidelines are actually not that far off from each other, but there is that one difference.

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