Header 1

Our future, our universe, and other weighty topics

Monday, May 21, 2018

Memory Experimenters Have Giant Claims but Low Statistical Power

Last week the BBC reported a science experiment with the headline “'Memory transplant' achieved in snails.” This was all over the science news on May 14. Scientific American reported it with a headline stating “Memory transferred between snails,” and other sites such as the New York Times site made similar matter-of-fact announcements of a discovery. But you need not think very hard to realize that there's something very fishy about such a story. How could someone possibly get decent evidence about a memory in a snail?

To explain why this story and similar stories do not tell us anything reliable about memory, we should consider the issue of small sample sizes in neuroscience studies. The issue was discussed in a paper in the journal Nature, one entitled Power failure: why small sample size undermines the reliability of neuroscience. The article tells us that neuroscience studies tend to be unreliable because they are using too small a sample size. When there is too small a sample size, there's a too high chance that the effect reported by a study is just a false alarm.

An article on this important Nature article states the following:

The group discovered that neuroscience as a field is tremendously underpowered, meaning that most experiments are too small to be likely to find the subtle effects being looked for and the effects that are found are far more likely to be false positives than previously thought. It is likely that many theories that were previously thought to be robust might be far weaker than previously imagined.

I can give a simple example illustrating the problem. Imagine you try to test extrasensory perception (ESP) using a few trials with your friends. You ask them to guess whether you are thinking of a man or a woman. Suppose you try only 10 trials with each friend, and the best result is that one friend guessed correctly 70% of the time. This would be very unconvincing as evidence of anything. There's about a 5 percent chance of getting such a result on any such test, purely by chance; and if you test with five people, you have perhaps 1 chance in 4 that one of them will be able to make 7 such guesses correctly, purely by chance. So having one friend get 7 out of 10 guesses correctly is no real evidence of anything. But if you used a much larger sample size it would be a different situation. For example, if you tried 1000 trials with a friend, and your friend guessed correctly 700 times, that would have a probability of less than 1 in a million. That would be much better evidence.

Now, the problem with many a neuroscience study is that very small sample sizes are being used. Such studies fail to provide convincing evidence for anything. The snail memory test is an example.

The study involved giving shocks to some snails, extracting RNA from their tiny brains, and then injecting that into other snails that had not been shocked. It was reported that such snails had a higher chance of withdrawing into their shells, as if they were afraid and remembered being shocked when they had not. But it might have been that such snails were merely acting randomly, not experiencing any fear memory transferred from the first set of snails. How can you have confidence that mere chance was not involved? You would have to do many trials or use a sample size that guarantees that sufficient trials will occur. This paper states that in order to have moderate confidence in results, getting what is called a statistical power of .8,  there should be at least 15 animals in each group. This statistical power of .8 is a standard for doing good science. 

But judging from the snail paper, the scientists did not do a large number of trials. Judging from the paper, the effect described involved only 7 snails (the number listed on lines 571 -572 of the paper). There is no mention of trying the test more than once on such snails. Such a result is completely unimpressive, and could easily have been achieved by pure chance, without any real “memory transfer” going on. Whether the snail does or does not withdraw into its shell is like a coin flip. It could easily be that by pure chance you might see some number of “into the shell withdrawals” that you interpret as “memory transfer.”

Whether a snail is withdrawing into its shell requires a subjective judgment, where scientists eager to see one result might let their bias influence their judgments about whether the snail withdrew into its shell or not. Also, a snail might withdraw into its shell simply because it has been injected with something, not because it is remembering something. Given such factors and the large chance of a false alarm when dealing with such a small sample size, this “snail memory transfer” experiment offers no compelling evidence for anything like memory transfer. We may also note the idea that RNA is storing long-term memories in animals is entirely implausible, because of RNA's very short lifetime. According to this source, RNA molecules typically last only about two minutes, with 10 to 20 percent lasting between 5 and 10 minutes. And according to this source, if you were to inject RNA into a bloodstream, the RNA molecules would be too large to pass through cell membranes.

The Tonegawa memory research lab at MIT periodically puts out sensational-sounding press releases on its animal experiments with memory. Among the headlines on its site are the following:

  • “Neuroscientists identify two neuron populations that encode happy or fearful memories.”
  • “Scientists identify neurons devoted to social memory.”
  • “Lost memories can be found.”
  • “Researchers find 'lost' memories”
  • “Neuroscientists reverse memories' emotional associations.”
  • “How we recall the past.”
  • “Neuroscientists identify brain circuit necessary for memory formation.”
  • “Neuroscientists plant false memories in the brain.”
  • “Researchers show that memories reside in specific brain cells.”
But when we take a close look at the issue of sample size and statistical power, and the actual experiments that underlie these claims, it seems that few or none of these claims are based on solid, convincing experimental evidence. Although the experiments underlying these claims are very fancy and high-tech, the experimental results seem to involve tiny sample sizes so small that very little of it qualifies as convincing evidence.

A typical experiment goes like this: (1) Some rodents are given electrical shocks; (2) the scientists try to figure out where in the rodent's brain the memory was; (3) the scientists then use an optogenetic switch to “light up” neurons in a similar part of another rodent's brain, one that was not fear trained; (4) a judgment is made on whether the rodent froze when such a thing was done.

Such experiments have the same problems I mentioned above with the snail experiment: the problem of subjective interpretations and alternate explanations. The MIT memory experiments typically involve a judgment of whether a mouse froze. But that may often be a hard judgment to make, particularly in borderline cases. Also, we have no way of telling whether a mouse is freezing because he is remembering something. It could be that the optogenetic zap that the mouse gets is itself sufficient to cause the mouse to freeze, regardless of whether it remembers something. If you're walking along, and someone shoots light or energy into your brain, you might stop merely because of the novel stimulus.

But the main problem with such MIT memory experiments is that they involve very small sample sizes, so small that all of the results could easily have happened purely because of chance. Let's look at some sample sizes, remembering that according to this scientific paper, there should be at least 15 animals in each group to have moderate confidence in your results, sufficient to reach the standard of a “statistical power of .8.”.

Let's start with their paper, “Memory retrieval by activating engram cells in mouse models of early Alzheimer’s disease,” which can be accessed from the link above after clicking underneath "Lost memories can be found." The paper states that “No statistical methods were used to predetermine sample size.” That means the authors did not do what they were supposed to have done to make sure their sample size was large enough. When we look at page 8 of the paper, we find that the sample sizes used were merely 8 mice in one group and 9 mice in another group. On page 2 we hear about a group with only 4 mice per group, and on page 4 we hear about a group with only 4 mice per group. Such a paltry sample size does not result in any decent statistical power, and the results cannot be trusted, since they very easily could be false alarms. The study therefore provides no convincing evidence of engram cells.

Another example is this paper by the MIT memory lab, with the grandiose title “Creating a False Memory in the Hippocampus.” When we look at Figure 2 and Figure 3, we see that the sample sizes used were paltry: the different groups of mice had only about 8 or 9 mice per group. Such a paltry sample size does not result in any decent statistical power, and the results cannot be trusted, since they very easily could be false alarms. No convincing evidence has been provided of creating a false memory.

A third example is this paper with the grandiose title “Optogenetic stimulation of a hippocampal engram activates fear memory recall.” Figure 2 tells us that in one of the groups of mice there were only 5 mice, and that in another group there were only 3 mice. Figure 3 tells us that in two other groups of mice there were only 12 mice. Figure 4 tells us that in some other group there was only 5 mice. Such a paltry sample size does not result in any decent statistical power, and the results cannot be trusted, since they very easily could be false alarms. No convincing evidence has been provided of artificially activating a fear memory by the use of optogenetics.

Another example is this paper entitled “Silent memory engrams as the basis for retrograde amnesia.” Figure 1 tells us that the number of mice in particular groups used for the study ranged between 4 and 12. Figures 2 and 3 tell us that the number of mice in particular groups used for the study ranged between 3 and 12. Such a paltry sample size does not result in any decent statistical power, and the results cannot be trusted, since they very easily could be false alarms.

The term “engram” means a cell or cells that store memories. Decades after the term was created, we still have no convincing evidence for the existence of engram cells. But memory researchers are shameless in using the term “engram” matter-of-factly even though no convincing evidence of an engram has been produced. So, for example, one of the MIT Lab papers may again and again refer to some cells they are studying as “engram cells,” as if they could try to convince us that such cells are actually engram cells by telling us again and again that they are engram cells. Doing this is rather like some ghost researcher matter-of-factly using the term “ghost blob” to refer to particular patches of infrared light that he is studying after using an infrared camera. Just as a blob of infrared light merely tells us only that some patch of air was slightly colder (not that such a blob is a ghost), a scientist observing a mouse freezing is merely entitled to say he saw a mouse freezing (not that the mouse is recalling a fear memory); and a scientist seeing a snail withdrawing into its shell is merely entitled to tell us that he saw a snail withdrawing into its shell (not that the snail was recalling some fear memory).

The relation between the chance of a false alarm and the statistical power of a study is clarified in this paper by R. M. Christley. The paper has an illuminating graph which I present below with some new captions that are a little more clear than the original captions. We see from this graph that if a study has a statistical power of only about .2, then the chance of the study giving a false alarm is something like 1 in 3 if there is a 50% chance of the effect existing, and much higher (such as 50% or greater) if there is less than a 50% chance of the effect existing. But if a study has a statistical power of only about .8, then the chance of the study giving a false alarm is only about 1 in 20 if there is a 50% chance of the effect existing, and much higher if there is less than a 50% chance of the effect existing. Animal studies using much fewer than 15 animals per study (such as those I have discussed) will result in the relatively high chance of false alarms shown in the green line.

false positive

The PLOS paper here analyzed 410 experiments involving fear conditioning with rodents, a large fraction of them memory experiments. The paper found that such experiments had a “mean normalized effect size” of only .29. An experiment with an effect size of only .29 is very weak, with a high chance of a false alarm. Effect size is discussed in detail here, where we learn that with an effect size of only .3, there's typically something like a 40 percent chance of a false alarm.

To determine whether a sample size is large enough, a scientific paper is supposed to do something called a sample size calculation. The PLOS paper here reported that only one of the 410 memory-related neuroscience papers it studied had such a calculation.  The PLOS paper reported that in order to achieve a moderately convincing effect size of .80, an experiment typically needs to have 15 animals per group; but only 12% of the experiments had that many animals per group. Referring to statistical power (a measure of how likely a result is to be real and not a false alarm), the PLOS paper states, “no correlation was observed between textual descriptions of results and power.” In plain English, that means that there's a whole lot of BS flying around when scientists describe their memory experiments, and that countless cases of very weak evidence have been described by scientists as if they were strong evidence.

Our science media shows very little sign of paying any attention to the statistical power of neuroscience research, partially because rigor is unprofitable. A site can make more money by trumpeting borderline weakly-suggestive research as if it were a demonstration of truth, because the more users click on a sensational-sounding headline, the more money the site make from ads. Our neuroscientists show little sign of paying much attention to whether their studies have a decent statistical power. For the neuroscientist, it's all about publishing as many papers as possible, so it's a better career move to do 5 underpowered small-sample studies (each with a high chance of a false alarm) than a single study with an adequate sample size and high statistical power.

Thursday, May 17, 2018

Three Fallacies in This Week's “Multiverse News” Story

May 14, 2018 was another day showing that a good deal of what you read in the science news has little relation to fact. Besides some misleading neuroscience headlines I'll discuss in another post, there were news stories about some cosmological research. Fox News covered it with a headline of “Scientists believe alien life may exist in other universes after discovering a mysterious 'force.'” The “force” referred to is the cosmological constant, which was discovered to exist more than 25 years ago. So the implication of the headline (that some new force was recently discovered) is bunk. The Live Science site reported the same research as “Aliens May Well Exist in a Parallel Universe, New Studies Find.” The Daily Mail reported the same research with the headline, "Our universe may be one of many with life." 

The studies in question were actually “no real news” type of affairs. They considered what is called the cosmological constant or dark energy, which is basically the same as the vacuum energy density or the energy density of empty space. The studies found that in some other universe such a thing might be up to 300 times greater without ruling out life in such a universe. This is “no real news” in the sense that this was already known.

What we have in our universe is a vacuum energy density or cosmological constant that seems not quite zero but very close to zero. This means that the vacuum of space is very close to being devoid of energy. So it's hardly a surprise that you could multiply by a few hundred times this “very close to nothing” energy density of the vacuum, without affecting the universe's habitability.

But our science news media has distorted such studies, drawing unwarranted conclusions from them. For example, the Live Science story claimed this: “According to a new pair of studies in the journal Monthly Notices of the Royal Astronomical Society, there’s a decent chance that life-fostering planets could exist in a parallel universe.” I will now explain three fallacies involved in such claims, which certainly do not follow from the studies in question.

Fallacy 1: The Fallacy of Mistaking “Could Be Much Different Without Ruining Things” with “Being Likely to Be Life-Compatible”

Let us consider some particular parameter in a universe: for example, the strength of the gravitational constant. Imagine you show that such a parameter could vary by 100 times without ruining the chances of life in our universe. Would such a parameter be likely to be compatible with life's existence in a random universe? Not at all. Whether a particular parameter could be much different without ruining a universe's habitability (call this Question A) is a much different question than whether such a parameter would be likely to have a value not ruining the chances of life in a random universe (call this Question B).

How can we calculate this Question B? You would have to numerically compare two ranges of values: (1) a range of values (call it Range A) that the parameter could have without preventing life in our universe; (2) a much larger set of values (call it Range B) that the parameter might possibly have had.

Let's try this in the case of the gravitational constant. We know that the universe has four fundamental forces (the gravitational force, the weak nuclear force, the electromagnetic force, and the strong nuclear force). We also know that the ratio between the strongest of the forces (the strong nuclear force) and the weakest of these forces (the gravitational force) is about 10 to the fortieth power or 1040. So in estimating the set of values that any of these four forces might have had in a possible universe, a reasonable approach would be to assume that any of them might have varied by a factor of 1040. So for the gravitational constant it would seem that Range B should be something like the range of values between a value 1040 times smaller than the current value of the gravitational constant and a value 1040 times larger than the current value of the gravitational constant. But in this case Range A would only be a microscopic fraction of this Range B, because there are reasons why life could not exist in our universe if the gravitational constant was much more than about 100 times larger or smaller.

The ratio between this Range A and Range B is actually about 1 in 10 to the thirty-seventh power. So in the case of the gravitational constant two things are true: (1) the current value of the constant could be no more than about a hundred times larger or smaller without ruining the universe's chance of life; (2) the chance of such luck in a random universe seems to be less than 1 in 10,000,000,000,000,000,000,000,000,000.

I can give an analogy. Imagine there's an office door that requires people entering to type their 10-digit social security number. Imagine there are 100 employees in the office. In this case there are 100 random numbers you can type that would get you inside the office. But there's still only a tiny chance of success with a random number. So you should not at all make the mistake of thinking, “There's a good chance of getting in; there are a hundred numbers that will get you in.” The chance of getting in with a random number is actually less than 1 in 100 million. And similarly, the chance of a random universe having a life-compatible gravitational constant is much less than 1 in a billion, even though there are multiple random values for such a constant that might be compatible with life.

In the case of the cosmological constant, we would have to consider both the Range A mentioned by these scientific papers (plus or minus 300 times) and also a vastly larger Range B representing possible values for the cosmological constant. The cosmological constant is determined by various quantum contributions to the vacuum energy density, and physicists have long told us that these contributions should be enormous. Calculations based on quantum mechanics indicate that the cosmological constant should actually be 1060 or 10120 times larger than it is. This is the problem (discussed here) called the “vacuum catastrophe” problem, the problem that reality is not matching theoretical predictions.

So the Range B for the cosmological constant should be any value between 0 and a value 1060 times stronger than its value in our universe. In a random universe the energy density of a vacuum could be anywhere between nothing and the energy density of a neutron star. In this case the Range A (a value between the cosmological constant's value in our universe and a value 300 times greater) is only a tiny fraction of the Range B – less than a millionth of a billionth.

So far from showing that “there’s a decent chance that life-fostering planets could exist in a parallel universe,” the very item being considered (the cosmological constant or vacuum energy density) is a reason for thinking that there would be less than one chance in a million billion of a random universe having properties compatible with life.

Fallacy 2: Assuming That a Universe's Habitability Depends On Only One Factor

The habitability of a universe depends on a very large number of factors, including all of these:

  • the strength of the electromagnetic force
  • the strength of the strong nuclear force binding atomic nuclei together
  • the strength of the gravitational force
  • the value of Planck's constant, a constant that appears very often in nuclear equations
  • the value of the speed of light
  • the extent of the vacuum energy density or cosmological constant
  • the expansion speed of an expanding universe
  • the ratio between the absolute value of the electric charge on the proton and the absolute value of the electric charge on the electron (very precisely 1.000000000000000 in our universe, as discussed here)
  • the ratio between the mass of the proton and the mass of the electron
  • the size of primordial density fluctuations
  • suitable law of nature, such as those allowing electromagnetism
  • the amount of entropy in the universe

All of these things have to be right for a universe to be habitable, for reasons discussed here and here. Below is a table listing some of the requirements for a universe to have civilizations (see here for a discussion of each item in the table). Click on the table to see it at better resolution.

Anthropic Principle

It is therefore a great fallacy for anyone to be hearing about some study regarding one particular cosmic parameter or fundamental constant, and then saying, “Oh, so it's not so hard for a universe to be habitable.” That's rather like some young lady saying, “Okay, I've got a good hairstyle, now I've got a good chance of becoming a movie star.” Just as becoming a movie star has many different requirements (such as looks, a good agent, lucky breaks, connections, and acting talent), having a universe compatible with life has many different requirements.

Fallacy 3: Assuming That a Habitable Universe Equals a Good Chance of a Planet with Intelligent Life

It is important not to confuse necessary conditions and sufficient conditions. A necessary condition is some condition that must be met in order for some thing to occur. A sufficient condition is something that will guarantee that such a thing will occur. For example, buying a lottery ticket is a necessary condition for winning a lottery jackpot, but not at all a sufficient condition for such a thing. Having your head cut off is not a necessary condition for death, but it is a sufficient condition for death, guaranteeing that someone will die.

In regard to the appearance of intelligent life on a planet, a habitable universe is a necessary condition for such an appearance, but not at all a sufficient condition for such a thing. Beyond the many conditions for a habitable universe, there are many additional conditions that must be met for life to get started in any universe: (1) the appearance of a genetic code; (2) the appearance at one spot of more than 100,000 base pairs achieving a functional end allowing a cell to reproduce; (3) the appearance of a molecule like DNA; (4) the appearance of a cell membrane. Then there are many additional improbable conditions that must be met for life to arise to the state of multicellular complexity and intelligence. These additional conditions are so steep that they might never occur in any of a million random universes, even if they all happened to be habitable.

There are many highly improbable conditions that must be met for any random universe to be either life-compatible or compatible with the existence of stars. For reasons discussed in this post, with overwhelming likelihood a random universe would be both lifeless and light-less. The bottom line on the cosmological constant or vacuum energy density is that it is one of many needles that must be threaded for you to have a universe compatible with life, one of many distant target bulls-eyes that must be hit to end up with a universe compatible with the existence of intelligent life.  

cosmic finetuning

Sunday, May 13, 2018

The Dubious Dogma That Thought Comes from the Frontal Lobes or Prefrontal Cortex

Scientists lack any coherent explanation for how a brain could generate thought or intellect. Thoughts are immaterial things, so how could they possibly be generated by material things such as neurons? We know how physical things can generate other physical things (such as continental plates generating earthquakes), and we know how mental things can generate other mental things (such as one idea leading to a related idea). But nobody can give a coherent explanation as to how a physical thing such as a brain could produce a mental thing such as a thought or idea.

Scientists often fall back on localization claims to try to hide this shortfall. A scientist who cannot explain the how of a brain making an idea or a decision will often try to use a where as a substitute, by suggesting that specific mental capabilities come from particular parts of the brain. A common claim is that higher thought comes from the frontal lobe of the brain. More specifically, someone may claim that higher thought comes from the front-most part of the frontal lobe, what is called the prefrontal cortex. But the evidence fails to strongly support such claims, and the evidence often conflicts with such claims.

We certainly do not know from brain scans that higher thought comes from the frontal lobe or the prefrontal cortex. With the exception of the auditory and visual cortex, which show clear signs of “lighting up” during visual or auditory perception, there is no part of the brain that shows more than about a 1 percent increase in activity when humans think, decide, or remember. As a technical paper states, “cognitive effects give signal changes on the order of 1%.”

Those visuals showing “activating regions” of the brain in red are typically making use of a deceptive data presentation technique in which mere 1 percent differences in activity (or less) are represented in red, making them looking like big differences when they're really tiny differences. When you run, your heart gives a very clear signal of being involved in such a thing – for your heart rate may increase by 50 percent. But when you think, decide, or remember an old memory, there is no part of your brain that gives any clear sign of shifting into high gear or being crucially involved in such a thing.

Interestingly, a recent scientific paper notes that "neuroimaging studies have shown that intelligent individuals, despite their larger brains, tend to exhibit lower rates of brain activity during reasoning." So here we have an inverse correlation between brain activity and thinking. 

Let us look at general intelligence and the frontal lobe. It is part of the dubious folklore of neuroscientists that the prefrontal cortex is some center of higher reasoning. But the scientific paper here tells us that patients with prefrontal damage "often have a remarkable absence of intellectual impairment, as measured by conventional IQ tests." The authors of the scientific paper tried an alternate approach, using a test of so-called "fluid" intelligence on 80 patients with prefrontal damage. They concluded "our findings do not support a connection between fluid intelligence and the frontal lobes." Table 7 of this study reveals that the average intelligence of the 80 patients with prefrontal cortex damage was 99.5 – only a tiny bit lower than the average IQ of 100. Table 8 tells us that two of the  patients with prefrontal cortex damage had genius IQs of higher than 140.

In a similar vein, the paper here tested IQ for 156 Vietnam veterans who had undergone frontal lobe brain injury during combat. If you do the math using Figure 5 in this paper, you get an average IQ of 98, only two points lower than average. You could plausibly explain that 2 point difference purely by assuming that those who got injured had a very slightly lower average intelligence (a plausible assumption given that smarter people would be more likely to have smart behavior reducing their chance of injury). Similarly, this study checked the IQ of 7 patients with prefrontal cortex damage, and found that they had an average IQ of 101.

It is sometimes claimed that the dorsolateral prefrontal cortex is the "CEO" of the brain. This study examined six patients with damage to the dorsolateral prefrontal cortex, and found that they had an average IQ of 104, above the average of 100. This study says, “We have studied numerous patients with bilateral lesions of the ventromedial prefrontal (VM) cortex” and that “most of these patients retain normal intellect, memory and problem-solving ability in laboratory settings.”

In the paper "Neurocognitive outcome after pediatric epilepsy surgery" by Elisabeth M. S. Sherman, we have some discussion of the effects on children of hemispherectomy, surgically removing half of their brains to stop seizures. Such a procedure involves a 50% reduction in the frontal lobe of the brain, and a 50% reduction of the prefrontal cortex. We are told this:

Cognitive levels in many children do not appear to be altered significantly by hemispherectomy. Several researchers have also noted increases in the intellectual functioning of some children following this procedure....Explanations for the lack of decline in intellectual function following hemispherectomy have not been well elucidated. 

Referring to a study by Gilliam, the paper states that of 21 children who had parts of their brains removed to treat epilepsy, including 10 who had surgery to the frontal lobe, none of the 10 patients with frontal lobe surgery had a decline in IQ post-operatively, and that two of the children with frontal lobe resections had "an increase in IQ greater than 10 points following surgery." 

The paper here gives precise before and after IQ scores for more than 50 children who had half of their brains removed in a hemispherectomy operation.  For one set of 31 patients, the IQ went down by an average of only 5 points. For another set of 15 patients, the IQ went down less than 1 point. For another set of 7 patients the IQ went up by 6 points. 

Now let us look at whether there is good evidence that decision making is generated by the prefrontal cortex. It should be first noted that the evidence discussed above discredits such an idea, because you can't perform well on an IQ test unless you have a good decision-making ability. Each IQ test question requires you to make a decision; none are tests of learned knowledge. For example, when an IQ test asks which of 5 figures most closely resembles a particular figure, that is something that requires you to make a decision rather than just remember something you have learned.

A 2002 scientific paper was entitled “Decision-making processes following damage to the prefrontal cortex.” The scientists who wrote the paper identified 19 patients with damage to the prefrontal cortex, and had them do various tests. Some of the results are below:
  • Patients with local orbitofrontal lesions performed normally (at control levels) on three-decision making tasks.
  • There was no statistically significant difference among the four frontal subgroups and controls on letter fluency or category fluency.
  • Pattern recognition performance (percentage correct) was not significantly impaired in either the combined frontal group or the five subgroups.
  • On spatial recognition (percentage correct), the combined frontal group were unimpaired relative to controls.
  • On a gambling test to determine decision making, “The combined frontal group did not show poorer decision making than controls... and there were no significant differences among the five subgroups.”
Based on the results above, you would have to conclude that the idea that the prefrontal cortex generates decisions or thoughts is false. But there's another test that neuroscientists use in cases such as these – a kind of very subtle and sneaky test. We might put this test under a category of “desperately seeking evidence of performance deterioration.

The test is called the “Iowa gambling task.” A person will sit in front of a computer screen that shows four card decks. The person can pick from any of the decks, and is told that when you pick a card, your money can be either increased or decreased. Normally decks A and B give you a much higher money reward, compared to decks C and D. For example, it might be that picking from deck A will normally give you about $100, and picking from decks C and D will normally give you only about $10. But there's a sneaky catch. Occasionally decks A and B will cause you to lose a large amount such as $1200.

So a person doing this test has to recognize a very subtle rule that can be detected only after 40 or 50 trials – that even though decks A and B normally give more money, they can cause big money subtractions, which means that it's really better to keep picking from decks C and D.

As a test of executive ability, the Iowa gambling task is dubious indeed. One reason is that it may be largely testing short-term memory or prolonged concentration rather than executive ability. Another reason is that it is debatable whether the assumption of the people applying this test (that picking from decks C and D is a wiser decision) is correct. It can be argued that the person who picks from decks A and B has made a correct short-term decision. Such a person is like an investor who continues to invest in the stock market because of nice annual gains even though he knows that about every 8 years or so, stock markets have nasty downturns in which investors lose 30% or so of their money. This wikipedia page on the Iowa gambling task gives some scientific papers that argue it is flawed, and should not be used to judge executive ability.  

In the paper I referred to above, the patients with prefrontal damage did worse on the Iowa gambling task, although whether that actually was inferior executive ability is debatable. We can summarize the paper by saying its tests provided no clear evidence that decisions are produced by the prefrontal cortex, and no clear evidence that damage to the prefrontal cortex significantly impairs executive ability.

Another dubious test used on some patients with frontal lobe damage is called the Wisconsin Card Sorting Test. Subjects are asked to put a card in one of 4 card stacks. As soon as they make a choice, they are told whether their choice was correct. We are told in 1:34 of this video that “After ten consecutive correct matches, the classification principle changes without warning.” So this test is also a subtle, sneaky type of test, not a straightforward test of executive ability. What it tests is the ability to discard a principle you have already adopted when the evidence no longer supports that principle. One paper says, “These findings strongly suggest that WCST scores cannot be regarded as valid nor specific markers of prefrontal lobe function.” 

The studies above are studies involving small numbers of unusual subjects with damage in the frontal lobes. Perhaps a much better way to consider the issue of how much cognition depends on the frontal lobes (or the prefrontal cortex) is to consider a much larger class of subjects: the many millions of people older than 60.

This scientific paper states this: “General linear model analyses revealed that the greatest age effects occurred in prefrontal cortex gray matter... with an average rate of volumetric decline of 4.9% per decade” after age 18. This should result in a decline in the prefrontal cortex gray matter of more than 20% by the time someone reaches 70. But we see nothing like a 20% decline in intelligence or decision-making ability in those who have reached the age of 70. People older than 70 still serve as presidents, congressmen, senators and CEO's. 

I could cite some statistics comparing the IQ tests of 20-year-olds and 70-year-olds, but then we would run into the confounding factor known as the Flynn Effect. The Flynn Effect is that for many decades, the performance of young people on IQ tests has been improving, with the improvement being about 3 points per decade. The study here states the following:

The Flynn effect was large enough to account for 100% of the variance in performance between age groups for cross-sectional analyses. After accounting for the Flynn effect, IQ was found to be relatively stable across the adult portion of the lifespan. Verbal abilities remain stable and even show gains through a large segment of the lifespan, while abilities measured by the Performance scale show modest declines from younger to older samples.

So the study finds that after we adjust for the Flynn effect, the IQ of people about 70 is about the same as people about 20. This finding is not at all what we should expect if the prefrontal cortex is responsible for intellectual capabilities, given a decline of about 20% that should occur in the prefrontal cortex between the age of 20 and 70.

I may note that the very fact of the Flynn effect is inconsistent with the dogma that our intelligence is a product of our brain. The Flynn effect, which involved an increase in IQ scores of about 3 percent per decade, went on for at least seven decades (although some think it is wearing off). During this time there was no change in human brains that could account for such a change.

Another relevant point is that the human brain is currently much smaller than it was previously. A science article in the mainstream Discover magazine tells us this: “Over the past 20,000 years, the average volume of the human male brain has decreased from 1,500 cubic centimeters to 1,350 cc, losing a chunk the size of a tennis ball.” But most people would guess that humans are smarter, or as least as smart, as those who lived 20,000 years ago.

A recent article on Aeon mentions how there is little correlation between brain size and intelligence, or a correlation between intelligence and the size of a frontal cortex. The article states the following:

Some of the most perspicacious animals are the corvids – crows, ravens, and rooks – which have brains less than 1 per cent the size of a human brain, but still perform feats of cognition comparable to chimpanzees and gorillas. Behavioural studies have shown that these birds can make and use tools, and recognise people on the street, feats that even many primates are not known to achieve. ….Among rodents, for instance, we can find the 80-gram capybara brain with 1.6 billion neurons and the 0.3-gram pygmy mouse brain with probably fewer than 60 million neurons. Despite a greater than 100-fold difference in brain size, these species live in similar habitats, display similarly social lifestyles, and do not display obvious differences in intelligence.

Consider the growth of intelligence in a child. A child is born with about as many neurons as it will ever have. During the period from birth to age 18, the child's intelligence seems to grow by perhaps 300%. But there is no corresponding brain growth.

There are, however, many new connections formed between brain cells. But an article at Neurosciencenews.com tells us the following:

The more intelligent a person, the fewer connections there are between the neurons in his cerebral cortex. This is the result of a study conducted by neuroscientists working with Dr Erhan Genç and Christoph Fraenz at Ruhr-Universität Bochum; the study was performed using a specific neuroimaging technique that provides insights into the wiring of the brain on a microstructural level.. The researchers associated the gathered data with each other and found out: the more intelligent a person, the fewer dendrites there are in their cerebral cortex.

Let's put some of these facts into a table listing predictions of the theory that your intelligence comes from your brain, comparing such predictions to reality.

Prediction of theory that intelligence comes from brain, specifically the frontal lobe or prefrontal cortex Reality
Injury to prefrontal cortex or frontal lobes should cause sharp drop in intelligence, as should hemispherectomy This does not generally occur
Human intelligence should not have increased since 1900, because there has been no change in brain size or
structure .
Since about 1930, IQ scores have risen by about 3 percent per decade (the Flynn Effect).
People about 70 should be much less intelligent than 20-year-olds, because of 5% volume decline in prefrontal cortex per decade. Adjusting for Flynn Effect, no such drop in intelligence occurs.
Humans today should be much more stupid than humans 20,000 years ago, because our brains are smaller by about the size of a tennis ball. Most people today would guess that humans are smarter, or at least as smart, as humans 20,000 years ago.
Elephants should be much smarter than humans, because their brains are three or four times heavier. Humans are actually smarter than elephants.
Crows should be very stupid, because their brains are tiny, and have no neocortex. Crows are astonishingly smart.
Greater number of connections in the brain should increase effective intelligence.  "The more intelligent a person, the fewer connections there are between the neurons in his cerebral cortex." -- neuroscience news cited above. 
Men should be about nine percent smarter than women, because their brains are about nine percent bigger. It is generally recognized that on average men are not significantly smarter than women.
Adults should not be much smarter than babies or toddlers, because they have no more brain cells than babies or toddlers. Adults seem to be much smarter than babies and toddlers.

We see from this table that the claim that intelligence comes from the brain (specifically the frontal lobe or prefrontal cortex) massively fails to predict reality correctly.

The evidence discussed here argues against the claim that the prefrontal cortex or the frontal lobe can be identified as the source of decision making or the center of higher thought in the brain. The evidence discussed here is consistent with the claim that human higher thought capability does not come from the brain but from some unknown other source. Such a claim is also supported by many other considerations discussed at this site, including (1) convincing and well-replicated laboratory evidence (discussed here and here) for psychic phenomena such as ESP, evidence suggesting that the mind has powers that cannot be explained by brain activity; (2) evidence for near-death experiences indicating minds can continue to function even when brains have shut down because the heart has stopped.

Wednesday, May 9, 2018

Dubious Statements in National Geographic's Show About Life's Origin

National Geographic has a new series called One Strange Rock, dealing with all the things that needed to go right in order for humans to exist. This is a promising premise for a TV show, a topic that receives way too little discussion on television. But I was disappointed by a recent episode in the series, which was entitled “Genesis” and dealt with the origin of life. Below are some of the misleading statements on the show.

That's what life needed to get started: energy.”

This statement was made by a narrator on the show. Energy may be a requirement for life to get started on a planet, but such an event requires enormously more than just energy. So citing energy as “what life needed to get started” is rather absurd, given so many other steep requirements.

We're all made of the same dead dust that makes the planet -- it's just mixed up differently.”

This idea of life as a mere mixture was stated more than once in the show. In another place a narrator stated that “it's hard to get the ingredients right,” again implying the idea that life will appear whenever some particular mixture of ingredients appears. But even the simplest life is more than just an appropriate mixture – it's a state of organization vastly greater than in any mere mixture.

Narrator says she was excited by the “thought that energy can make lifeless stuff come alive.”

One of the show's narrators said this after mentioning origin of life experiments of the 1950's. Again, the show suggested the completely erroneous idea that mere energy can create life. The idea was further enforced by a long sequence showing a lightning rod technician climbing high up a skyscraper. Someone watching the show might have said, “Wow, I didn't know that – maybe you'll get life after just the right lightning flash.”

If you want to make stardust into life, there's a bit more to it than just add water.”

This statement implied that it is pretty easy to make life, just a “bit more” than adding water to dust. This is rather absurd considering the mountainous requirements for the origin of life, which I'll mention near the end of this post.

The origin of all of us was fired out of a hot chimney at the bottom of an ocean.

This statement was made by a narrator after discussing the theory that life originated in hydrothermal vents. Since such a theory is purely speculative, the idea should have not been described as fact.

A hydrothermal vent (credit: NASA)

The claim the DNA has every detail of what makes you you.

The idea that DNA has every detail of what makes you you is very much erroneous. For one thing, you are largely a mental and intellectual thing consisting of your attitudes, beliefs, principles, and memories, and none of these are specified by DNA. It is also not even true that DNA specifies your body plan. The idea of DNA as a blueprint for constructing a human is unfounded, for the reasons I discuss at length in this post. DNA is best described as an ingredient list. It mainly specifies the amino acids to build particular proteins. We do not understand how the linear sequences of amino acids specified in DNA turn into the elaborate three-dimensional shapes of protein molecules (which is the mystery of protein folding), and we also do not understand how a speck-sized human egg is able to grow to became a human baby (the mystery of morphogenesis).

The claim that carbon can connect in almost infinite ways with other elements to create all the molecules for a living cell.

Strictly speaking, this statement was not inaccurate, but it was highly misleading in the sense of implying that incredibly complicated molecules such as protein molecules or DNA molecules are somehow consequences of carbon or things that we might predict from what is known about carbon. They are not any such things, but are instead things that could possibly be created out of carbon and other elements given incredibly improbable luck. Saying that carbon can connect with other elements to make the molecules needed for life is rather like saying that the scrabble squares in your Scrabble box can connect together to form meaningful instructions. In both cases this is something that will only happen given deliberate intention or incredibly unlikely luck.

A person watching the National Geographic “Genesis” TV show might have gone away with the idea the origin of life was pretty easy. That's because the show totally failed to mention the main thing it should have mentioned: that even the simplest life is a state of organization vastly greatly than that of non-life. A team of 9 scientists wrote a scientific paper entitled, “Essential genes of a minimal bacterium.” It analyzed a type of bacteria (Mycoplasma genitalium) that has “the smallest genome of any organism that can be grown in pure culture.” According to wikipedia's article, this bacteria has 525 genes consisting of 580,070 base pairs. The paper concluded that 382 of this bacteria's protein-coding genes (72 percent) are essential. So multiplying that 580,070 by 72 percent, we get a figure of about 418,000 base pairs in the genome that are essential functionality. So even the most primitive microorganism known to us seems to need a minimum of more than 400,000 base pairs in its DNA. For such a state of organization to have appeared from non-life would have required what we must call an organization explosion or an information explosion -- as would the appearance of the genetic code.

We could imagine various ways in which a TV show could have conveyed the idea of an organization explosion as big as the one needed for life to appear from non-life. For example, on a TV set we might have seen the host with one of those transparent lottery ball spinners. Then the show might have shown the host pouring into the lottery ball spinner ten or twenty types of ingredients: metal nuts, screws, nails, strips of wood, strips of wire, strips of steel, steel angle brackets, and so forth. Then we could see the TV host spinning the lottery ball spinner. We then could have been told that for life to originate from non-life, it would be like this random chamber of ingredients forming not merely into a machine, but a machine capable of making copies of itself (with each of the copies also being capable of making copies of themselves).

Then the TV viewer would have got a proper idea of how miraculous would have been the luck needed for such an origin of life from non-life – an idea completely different from the “just add water and zap a good mixture of dust” drivel suggested by National Geographic's TV show.

Postscript: A comparable show was a NOVA Wonders episode on the search for extraterrestrial life. The transcript is here. There was a long narration  that made no mention of the great complexity of even the simplest life. There was a scientist named Kevin Hand who stated this about Jupiter's moon Europa: "So, if we found amino acids in ice, that could be a pretty strong sign of life within that ocean." But it would be no such thing. Life requires not only DNA but many proteins, each of which is a very complex functional arrangement of many amino acids of different types. Finding some amino acids is no more a strong sign of life than finding some stones in the woods is a sign  there's a stone house over the hill.