They Don't Sound Like They Know How Minds Could Arise Neurally

Neuroscientists frequently claim that minds come from brains. But this claim is simply a speech custom of neuroscientists rather than anything they have established through observations or experiments. When people attempt to produce evidence to back up their claim that minds are made by brains, such attempts do not hold up well to critical scrutiny. A recent such attempt was a long review article in "The Scientist" magazine, one entitled “The Biological Roots of Intelligence.” Let's look at why this article by Shawna Williams fails to establish the claim that your thinking is produced by your brain.

The first thing mentioned by Williams is the Flynn Effect. She notes the following:

Children in Japan, for example, gained an average of 20 points on a test known as the Wechsler Intelligence Scale for Children between 1951 and 1975. In France, the average 18-year-old man performed 25 points better on a reasoning test in 1974 than did his 1949 counterpart.

But how could this be true if our brains were producing our minds? There was no major change in brains between 1949-1951 and 1974-1975. So the Flynn Effect is actually hard-to-explain under the assumption that brains make minds.

The Williams essay then tells us, “A recent study of 1,475 adolescents across Europe reported that intelligence, as measured by a cognitive test, was associated with a panoply of biological features.” But if you actually look at that study, you will find it reports only a very slight relation between intelligence and the brain. For example, the authors say that a difference in gray matter in the striatum can account for less than 1% of the variation in scores, and that a difference in “polygenic scores” can account for less than 1% of the variation in scores. After doing some more statistical analysis, some of these faint effects seemed to disappear. The authors state “in this additional analysis gray matter in striatum showed no significant association” with IQ. At the end of their paper, the authors state this about their study: “The effect sizes studied are small but in the same range as previous studies (2.4% in previous structural imaging studies and up to 4.8% for previous polygenic scores).” Such very small percentages (of between about 1% and 3%) certainly do not add up to any good evidence that your intelligence comes from your brain.

One reason you should not at all be persuaded by such small effects is that they could easily be results that won't be replicated on a consistent basis. Imagine 20 different teams of neuroscientists comparing some group of brain scans and genomes to the corresponding IQ scores. If one of the teams of scientists check for 100 different things, they could easily get a few slight apparent correlations purely because of random variations in data that had nothing to do with a real biological root of intelligence. It also could be that 9 out of 10 scientists looking for such correlations find nothing, and don't bother to publish their data (or have their papers rejected because of the bias against null results). The 1 in 10 teams of scientists getting a slight correlation because of random variations might be the ones who end up getting their papers published.

Later Williams refers to a study by Richard Haier that scanned the brains of people while they were problem solving. But she quotes Haier as saying, “The people with the highest test scores actually showed the lowest brain activity.” Oops, this is the exact opposite of what we would expect if our brains were producing our minds. Williams states, “Some researchers are beginning to question the premise that the key to intelligence can be seen in the anatomical features of the brain.” Again, this is not something that inspires confidence in the dogma that brains make minds.

Later in a box labeled “Parsing Smartness,” Williams confesses, “The biological basis for variations in human intelligence is not well understood.” Why would that be if our brains were producing our minds? In the same box we read this: “One well-known hypothesis, backed by evidence from brain scans and studies of people with brain lesions, proposes that intelligence is seated in particular clusters of neurons in the brain, many of them located in the prefrontal and parietal cortices.” But you do not explain how a brain could produce intelligence by pointing to some part of the brain, and saying that such a part is where the effect is coming from (just as I would not explain how I could produce a thunderstorm if I told you that my thunderstorm creation ability comes from my left thumb). The long-stated claim that intelligence and judgment comes from the prefrontal cortex is actually not well-supported by facts, as you can read about in this long discussion of the evidence related to this claim, which discusses many things that contradict such a claim.

In the same “Parsing Smartness” box we read the following:

Researchers have also proposed a slew of other hypotheses to explain individual variation in human intelligence. The variety of proposed mechanisms underlines the scientific uncertainty about just how intelligence arises.

From this it sounds like our neuroscientists are vacillating all over the map, without any clear basis for claiming that minds or intelligence comes from brains. The Williams essay then has a quote from a neuroscientist, who says, “General intelligence originates from individual differences in the system-wide topology and dynamics of the human brain.” That's just empty phraseology that means nothing. You don't explain how people are able to think and understand by merely suggesting it comes from “differences.”

Referring to the problem of how intelligence arises, Williams states, “Santarnecchi finds himself frustrated that research has not yielded more-concrete answers about what he considers one of neuroscience’s central problems.” Oops, sounds like our neuroscientists don't really have any concrete reasons for believing in biological roots of intelligence. Later the Williams essay states, “Von Stumm is skeptical that genetic data will yield useful information in the near term about how intelligence results from the brain’s structure or function.” Such a statement seems to clash with the author's claim that there are biological roots of intelligence.

Williams later states the following: “In a meta-analysis published earlier this year, a team led by then University of Edinburgh neuropsychologist Stuart Ritchie (now at King’s College London) sifted out confounding factors from data reported in multiple studies and found that schooling—regardless of age or level of education—raises IQ by an average of one to five points per year.” If that's true, even after reaching adulthood each year of schooling raises your IQ. But why would that be so if your brain was generating your mind? An adult's brain doesn't get bigger when he is being educated. In fact, the density of synapses in the brain sharply declines between the age of 12 and 22.

Next Williams refers to “the biology of intelligence that remains a black box.” As every computer programmer knows, a black box means some mysterious thing you don't understand. Similarly, Williams later refers to the “intractable phenomenon of intelligence.” But why would our neuroscientists still not understand it if brains actually made minds?

Shawna Williams was supposed to be writing a long essay that would sum up all the best evidence that intelligence comes from the brain. But she fails to produce any convincing evidence for that dubious claim. And along the way, several of the statements and quotes in her long essay give us reason to doubt that there is any such thing as “biological roots of intelligence.” It's not Shawna's fault. The problem is that the evidence just doesn't really suggest that brains make minds. While there are a few little things here and there which may seem to whisper that maybe your brain makes your mind, there are other things which speak in a louder voice that brains do not make minds. Among many such things is the fact that hemispherectomy operations (in which half of a brain is removed to stop seizures) do not usually have a major effect on intelligence, and the fact that a French man managed to long hold a job as a civil servant even when 90% of his brain was destroyed by disease.