For the final book in 2018, I completed Russell Poldrack's, The New Mind Readers: What Neuroimaging Can and Cannot Reveal about Our Thoughts. He is a professor at the Stanford Neuroscience Institute.
fMRI, the new science
The book is about fMRI, which stands for Functional MRI scanning, which has allowed researchers to peer closely at how the brain works, as the mind works. The basic observation is that blood flows more to the area of the brain that is activated. For example if we see a wild animal and experience fear, blood flows to that part of the brain that causes that emotion to arise - and the fMRI captures it.
There are two basic disadvantages of the fMRI approach. Firstly, the blood flow process is a lot slower than the speed with which the neurons work. So the speed with which fMRI can capture the brain's actions is many orders of magnitude slower than the speed with which the brain works. Secondly, what the fMRI is seeing is not all that clear. In Poldrack's description, fMRI is like, "buying a digital camera with more megapixels but then taking photos through a foggy lens."
Despite these two fairly significant disadvantages, fMRI has revolutionized our understanding of the brain and its relationship to the mind.
Grow a brain
It turns out that our parents were wise when they admonished as as teens when we were asked to "grow a brain." Turns out that we can!
Firstly the frontal lobe that is responsible for executive function is underdeveloped for teens and thus their decision making, not just by experience, but by actual functional capability is undeveloped. The frontal lobe of the brain continues to develop beyond teen years into young adulthood.
Poldrack poses a nerve wracking conundrum in this regard.
If the above is true about teen brains - what about the true story of a teenager murdering an elderly woman and putting her into a car and pushing her off a cliff? How should this teenager be punished?
In a more pleasant example of "growing a brain," the book describes how musicians grow a different brain compared to non-musicians.
Musical experience changes both the structure and function of the brain, in direct relation to the amount of experience. One of the best-established findings is that the corpus callosum (the bundle of fibers connecting the brain’s two hemispheres) is thicker in musicians compared with nonmusicians, and these changes are particularly evident in musicians who started learning music at an early age.
Poldrack concludes, that this probably reflects the need for greater communication between the two hemispheres during musical performance, especially for players of keyboard instruments who have to coordinate their two hands.
Dopamine
Dopamine is a chemical in the brain released by neurons to send signals between specific neurons in the brain. In my reading, this might be the best known link between mind and brain. Dopamine neurons are constantly telling the rest of the brain how good the world is in comparison to our predictions, turning up their activity when the world exceeds our expectations and turning down when the world disappoints us.
The role of dopamine in addiction was a pretty powerful section in the book. Poldrack describes addiction as the result of a mismatch between our evolved brain and our modern environment. That is the context in which one is activating the release of dopamines is as important as the amount of drugs someone is consuming.
In a telling anecdote, Poldrack describes significant portion of the US veterans describing themselves as addicted to heroin while in Vietnam. However, vastly lower number reported being addicted upon returning to the US.
Kahneman meet Poldrack
Thinking Fast and Thinking Slow was a global best selling book by Nobel Prize winning Behavioral Economist Daniel Kahneman. Kahneman proposed in his Prospect Theory, that there are two levels of thinking in our brains - System 1 and System 2. System 1 is the fight or flight part of our brain and System 2 is the more goal oriented, systematic part of our brain. Kahneman arrived at this theory by observing how people made decisions.
In the perfect test case of mind meets brain, Poldrack wanted to see if Kahneman's theory holds up under fMRI imaging!
In particular, Poldrack tested two key concepts of Kahneman. First, that the psychological impact of a loss is greater than the impact of the same amount of gain. And second, that people will often behave differently depending on how a choice is described (or, how it is “framed”); when an outcome is described in terms of avoiding a loss people are more likely to take risks, compared to the same outcome described in terms of a gain.
In one of the most exciting parts of the book, Poldrack describes how they saw that the difference in brain responses to losses versus gains tracked the subjects’ choices, such that people who were more averse to losses in their choices also had a larger difference between the response to losses versus gains in their brain. Their study provided the first direct evidence from neuroscience in favor of prospect theory.
Detection of Alzheimer's Disease
One of the exciting developments is that the fMRI technique can be one of the tools used in understanding and detecting Alzheimer's disease. fMRI and other types of imaging show that there is a specific set of brain regions that is important for memory that starts to malfunction early in the development of Alzheimer’s disease. In particular, imaging allows researchers to quantify the amount of the damaging protein known as amyloid throughout the brain. Using this technique, they were able to demonstrate that the network of regions involved in memory also had the highest levels of amyloid, as well as showing the greatest amount of atrophy.
Also, sometimes thinner cortex (the outer layer of the brain) is bad, as in Alzheimer’s disease, where the cortex becomes overly thin.
In other cases thicker cortex can be bad; for example, many studies have reported that autistic individuals have thicker cortex in some parts of the brain compared to healthy controls.
Lies, damned lies and statistics
The most surprising insight from the book, was a universal truth that stood above the findings from fMRI. That was about statisitcs!
Poldrack repeatedly and throughout the book constantly cautions that a new scientific tool need not make good science. The instinct of the research community and society at large is to be enamored by the toy, and start making claims without validation.
He constantly tests fMRI findings against these statistical traps:
- Is the study with a small sample?
- Is the study design too flexible?
- Is the field the latest "in thing"?
- Is the data being protected and not shared?
He consistently uses these tests to ensure that claims from fMRI tests are not overstated.
This becomes rather serious if one considers criminality and legal procedure.
fMRI started being touted as being able to become a lie detector and was being purported to find guilt or innocence of the accused. The courts finally ruled that fMRI was not allowed in legal proceedings.
Summary
Poldrack provides one of the most salient definitions of science I have read. He says:
"It is important to remember that science is not simply a body of knowledge, but rather a way of asking questions.
It’s not guaranteed to give us the right answer, and in fact we are pretty sure that many of the ideas we hold right now will be overturned in the long run.
The importance of the scientific method is what it drives us to do: Rather than asking how we can find support for our ideas, science drives us to find out how we might be wrong.
The constant questioning and self-doubt are ultimately the best way that we know to keep from fooling ourselves."
Our brain uses the power of approximately a 20 watt light bulb, yet is such a powerful computing and decision making organ. fMRI has shown that the brain is not the body’s only computer—for example, the gut has its own as well, with about half a billion neurons.
In the hands of thoughtful and careful scientists like Russell Poldrack, fMRI shows great promise as a powerful new tool that is opening up a new world of understanding of ourselves, of our bodies and most importantly, of our brains.
fMRI, the new science
There are two basic disadvantages of the fMRI approach. Firstly, the blood flow process is a lot slower than the speed with which the neurons work. So the speed with which fMRI can capture the brain's actions is many orders of magnitude slower than the speed with which the brain works. Secondly, what the fMRI is seeing is not all that clear. In Poldrack's description, fMRI is like, "buying a digital camera with more megapixels but then taking photos through a foggy lens."
Despite these two fairly significant disadvantages, fMRI has revolutionized our understanding of the brain and its relationship to the mind.
Grow a brain
It turns out that our parents were wise when they admonished as as teens when we were asked to "grow a brain." Turns out that we can!
Firstly the frontal lobe that is responsible for executive function is underdeveloped for teens and thus their decision making, not just by experience, but by actual functional capability is undeveloped. The frontal lobe of the brain continues to develop beyond teen years into young adulthood.
Poldrack poses a nerve wracking conundrum in this regard.
If the above is true about teen brains - what about the true story of a teenager murdering an elderly woman and putting her into a car and pushing her off a cliff? How should this teenager be punished?
In a more pleasant example of "growing a brain," the book describes how musicians grow a different brain compared to non-musicians.
Musical experience changes both the structure and function of the brain, in direct relation to the amount of experience. One of the best-established findings is that the corpus callosum (the bundle of fibers connecting the brain’s two hemispheres) is thicker in musicians compared with nonmusicians, and these changes are particularly evident in musicians who started learning music at an early age.
Poldrack concludes, that this probably reflects the need for greater communication between the two hemispheres during musical performance, especially for players of keyboard instruments who have to coordinate their two hands.
Dopamine
Dopamine is a chemical in the brain released by neurons to send signals between specific neurons in the brain. In my reading, this might be the best known link between mind and brain. Dopamine neurons are constantly telling the rest of the brain how good the world is in comparison to our predictions, turning up their activity when the world exceeds our expectations and turning down when the world disappoints us.
The role of dopamine in addiction was a pretty powerful section in the book. Poldrack describes addiction as the result of a mismatch between our evolved brain and our modern environment. That is the context in which one is activating the release of dopamines is as important as the amount of drugs someone is consuming.
In a telling anecdote, Poldrack describes significant portion of the US veterans describing themselves as addicted to heroin while in Vietnam. However, vastly lower number reported being addicted upon returning to the US.
Kahneman meet Poldrack
Thinking Fast and Thinking Slow was a global best selling book by Nobel Prize winning Behavioral Economist Daniel Kahneman. Kahneman proposed in his Prospect Theory, that there are two levels of thinking in our brains - System 1 and System 2. System 1 is the fight or flight part of our brain and System 2 is the more goal oriented, systematic part of our brain. Kahneman arrived at this theory by observing how people made decisions.
In the perfect test case of mind meets brain, Poldrack wanted to see if Kahneman's theory holds up under fMRI imaging!
In particular, Poldrack tested two key concepts of Kahneman. First, that the psychological impact of a loss is greater than the impact of the same amount of gain. And second, that people will often behave differently depending on how a choice is described (or, how it is “framed”); when an outcome is described in terms of avoiding a loss people are more likely to take risks, compared to the same outcome described in terms of a gain.
In one of the most exciting parts of the book, Poldrack describes how they saw that the difference in brain responses to losses versus gains tracked the subjects’ choices, such that people who were more averse to losses in their choices also had a larger difference between the response to losses versus gains in their brain. Their study provided the first direct evidence from neuroscience in favor of prospect theory.
Detection of Alzheimer's Disease
One of the exciting developments is that the fMRI technique can be one of the tools used in understanding and detecting Alzheimer's disease. fMRI and other types of imaging show that there is a specific set of brain regions that is important for memory that starts to malfunction early in the development of Alzheimer’s disease. In particular, imaging allows researchers to quantify the amount of the damaging protein known as amyloid throughout the brain. Using this technique, they were able to demonstrate that the network of regions involved in memory also had the highest levels of amyloid, as well as showing the greatest amount of atrophy.
Also, sometimes thinner cortex (the outer layer of the brain) is bad, as in Alzheimer’s disease, where the cortex becomes overly thin.
In other cases thicker cortex can be bad; for example, many studies have reported that autistic individuals have thicker cortex in some parts of the brain compared to healthy controls.
Lies, damned lies and statistics
The most surprising insight from the book, was a universal truth that stood above the findings from fMRI. That was about statisitcs!
Poldrack repeatedly and throughout the book constantly cautions that a new scientific tool need not make good science. The instinct of the research community and society at large is to be enamored by the toy, and start making claims without validation.
He constantly tests fMRI findings against these statistical traps:
- Is the study with a small sample?
- Is the study design too flexible?
- Is the field the latest "in thing"?
- Is the data being protected and not shared?
He consistently uses these tests to ensure that claims from fMRI tests are not overstated.
This becomes rather serious if one considers criminality and legal procedure.
fMRI started being touted as being able to become a lie detector and was being purported to find guilt or innocence of the accused. The courts finally ruled that fMRI was not allowed in legal proceedings.
Summary
Poldrack provides one of the most salient definitions of science I have read. He says:
"It is important to remember that science is not simply a body of knowledge, but rather a way of asking questions.
It’s not guaranteed to give us the right answer, and in fact we are pretty sure that many of the ideas we hold right now will be overturned in the long run.
The importance of the scientific method is what it drives us to do: Rather than asking how we can find support for our ideas, science drives us to find out how we might be wrong.
The constant questioning and self-doubt are ultimately the best way that we know to keep from fooling ourselves."
Our brain uses the power of approximately a 20 watt light bulb, yet is such a powerful computing and decision making organ. fMRI has shown that the brain is not the body’s only computer—for example, the gut has its own as well, with about half a billion neurons.
In the hands of thoughtful and careful scientists like Russell Poldrack, fMRI shows great promise as a powerful new tool that is opening up a new world of understanding of ourselves, of our bodies and most importantly, of our brains.
4 comments:
When reading this bit…
Poldrack describes addiction as the result of a mismatch between our evolved brain and our modern environment.
It reminded me of this bit from Memetic Tribes and Culture War 2.0 …
Stimulation and The Sobriety Crisis. Is the image of a beetle hopelessly attempting to have sex with an empty beer bottle the perfect metaphor for the state of humanity? In 2011 Darryl Gwynne and David Rentz won the Ig Nobel Prize for their research on the male jewel beetle’s proclivity to attempt copulation with littered Australian beer stubbies. They found that these discarded bottles greatly attracted the male jewel beetle because their size, coloring, and dimpled design were similar to the male jewel beetle’s female counterpart. In fact, according to Darryl Gwynne, the male beetle found the beer bottle so attractive that they ignored the females and their “attempts to copulate with stubby beer bottles continue until they are killed by the hot desert sun or by foraging ants.”
This phenomenon is known as an evolutionary trap: adaptive instincts turn maladaptive due to exposure to supernormal stimuli; magnified and more attractive versions of evolved stimulus. Nikolaas Tinbergen, the ethologist who coined the term supernormal stimuli, demonstrated that he could trick birds, fish, and insects into evolutionary traps using exaggerated dummy objects designed to trigger their instincts. In Supernormal Stimuli: How Primal Urges Overran Their Evolutionary Purpose, psychologist Deirdre Barrett points out that humans are just as fallible to these superstimuli. Whether it be junk food, laugh tracks, pornography, or likes on social media, these artificial triggers addict us and hijack our agency.
I especially liked the “Lies, damned lies and statistics” section…
Poldrack repeatedly and throughout the book constantly cautions that a new scientific tool need not make good science. The instinct of the research community and society at large is to be enamored by the toy, and start making claims without validation.
Which has been a real problem with the popularization of fMRI research results. It’s a new technology that’s allowed us to peek inside a living brain for the first time. But it’s a technology closer to Galileo’s crude telescope than the Hubble. Or like the first double-slit experiment giving us a hint at what’s going on at the quantum level, vs today’s large hadron collider results. A long way to go before getting deeply meaningful results. So some humility is in order, which this writer seems to possess.
Many thanks for your very thoughtful book reviews - it’s been great when our interests have overlapped, but even more so when you highlighted a book I had not seen!!
Thanks for your well researched and very interesting posts throughout the year. I really enjoy reading them.
Good writeup. And the study of the brain is so recent. What will it be with deeper understanding 50 years down the line?!
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