Lab Talk

Intelligence and Neuroscience

Intelligence and Neuroscience

Intelligence research has been the domain of psychology and sociology and barely intersects with neuroscience.  Yet intelligence has everything to do with the brain, and integrating these fields into a common framework is essential.

Taking on Intelligence

The study of intelligence has its roots in the 1800s with the polymath Francis Galton, and the publication of the Origin of Species by his cousin Charles Darwin.  On reading Origin of Species Galton wrote to Darwin that:

I have laid it down in the full enjoyment of a feeling that one rarely experiences after boyish days, of having been initiated into an entirely new province of knowledge, which, nevertheless, connects itself with other things in a thousand ways.

Darwin’s work, demonstrating that particular features could be selectively bred and were therefore inherited, was focused around plants and animals.  Galton wondered whether this could apply to man’s intellect as well, leading to a several decades long inquiry centered on the question of whether intelligence, like physical traits, were inherited or created.  It was he who coined the term nature versus nurture.

An obvious challenge at the time was that there was yet no ‘measure’ of intelligence of any kind.  As a proxy Galton considered ‘noteworthy accomplishments’ that were thought to be inherently intelligent. But what is a noteworthy accomplishment that is inherently ‘intelligent’?  Galton eliminated nobility, legislature and army from the study where he states that social position and class took precedence over able intellect. Instead he focused on the fields of science, literature, music and law where he believed intellect dominated. Using lists of noteworthy people he found that anywhere from 1 in 3 to 1 in 7 people have male relatives who are also noteworthy, he found. An exceptionally high number when considering the size of the population at large.  This led Galton to the conclusion that intelligence was likely an inherited trait.  Based just on his evidence, alternative explanations are plenty.  Nonetheless, it was the first probing of its kind and culminated in a book titled ‘Hereditary Genius’ published in 1869.

The idea that intelligence could potentially be hereditary was novel. On reading it Darwin penned a letter to Galton in which he wrote:

I have only read about 50 pages of your book (to the Judges), but I must exhale myself, else something will go wrong in my inside. I do not think I ever in all my life read anything more interesting and original… You have made a convert of an opponent in one sense, for I have always maintained that, excepting fools, men did not differ much in intellect, only in zeal and hard work; and I still think this is an eminently important difference.

150 years of Intelligence Research

It has been 150 years since then and the field of intelligence research has grown in two directions.  The first has been in the development of methods of measuring intelligence or IQ.  This began with Spearman’s idea of g or a general mental energy and the Binet-Simon scales developed at the turn of the century to stream French children entering primary school. This was followed by development of the Stanford-Binet IQ tests and subsequently the Wechsler Intelligence scales.  Recent years have given way to ideas around multiple intelligences and emotional intelligence. Debates still rage over what is a valid measure of intelligence.

The second major area of research and debate has been about the role of genes and environment in intelligence.  Since Galton’s early inquiry, many have joined the debate.  From Jensen’s equations and explanations that left little to environment, and Flynn’s studies that demonstrate a greater environmental component, this has been a field fraught with controversy and emotion.  Gene’s matter, so does environment, but how, and by how much?

The Brain and Intelligence

Missing in large part from these debates is the neuroscience community.  Intelligence is about the brain, and yet our understanding of how the physiology of the brain gives rise to intelligence is nascent.  A small group of researchers have sought to find links using brain imaging. For example, relationships have been found between intelligence and glucose metabolism with PET, the connectivity of white matter tracts using diffusion tensor imaging, and the overall integration of the brain using fMRI.

see related post Dendrite Complexity and Intelligence

However, aside from some small pockets of research, the neuroscience community has taken its own direction  (the EEG field is conspicuous in its paucity of intelligence research).  Few neuroscientists will speak of intelligence in the same language or constructs as the Intelligence research community, who are largely from psychology or sociology.  Rather neuroscientists have different cognitive constructs and are more likely to speak of Executive Function rather than intelligence.  Executive Function is a concept developed around the idea of self-control and inhibition that can enable attention and focus on a task at hand.   Without a common language or framework, however, it is difficult to make the links between such understanding of the brain and intelligence.

The lack of integration of these fields is unfortunate since it ultimately hinders our ability to move forward.  Yet integration of these fields is crucial.  At a societal level the most important questions rest around what gives rise to intelligence, and what the drivers are at the level of brain physiology.   It is not until we really understand what those are that we can really change outcomes.

see related post Cognitive Health: Defining and Measuring it




2 thoughts on “Intelligence and Neuroscience

  1. I commented to 20aug 2018

    Interesting, I have a big doubt that intelligence can be measured based on the self control. I can only take myself and my observations of people around me as an example, so the comment is far from scientific, but I am a very chaotic person and have a hard time focusing on one thing at a time , yet in my life I have achieved higher results then most my peers, I speak 6 languages fluently and communicate in a handful more, was a multinational entrepreneur at the age of 25 and created several companies since. I have achieved both academic and professional success, though one could aways argue that I would have achieved much more if I was more focused.
    The way I see it is that when so many ideas come to you it is very hard , if not impossible to be very organized and focused. I also know of People in my surrounding that are highly focused and achieve exceptionally well in their managing corporate positions, but are unable to actually “invent” anything, rather they are perfect manual readers and execute schedules with a Swiss precision. The same people, come to think, of it should show a stoic calm in case of crisis, yet there I totally take over, my mind focuses like a laser in crisis situations or accidents, while the 2 people I just described literally “lose it”.
    One could argue that the combination of methodical work and concentration mixed with huge creativity and ability to think beyond the boarders is what genius is about , but I suspect that those states are exceptional.
    In my own case I have an exteeme ability to focus SOMETIMES. When I invent, when I put together loser ends that float like soap bubbles in my head, I’m able to work non-stop for tens of hours not matter where I am ( assuming I can have a pen because I need to draw all as it floats in), yet 95%of the time I feel most my energy and thoughts are lost out into space and I struggle with hubdreds of unfinished tasks on my desk , shifting the paper and files.
    Curious to follow the mix of neuroscience and studies of intelligence as I see the same tendency , the lack of focus, in 2 of my 3 small children ( the third is completely different, learns in way I have not yet grasped)yet they are all very advanced compared to their peers, speaking 3 languages fluently, are self taught readers at the age of 4, and have mathematical skills mostly learning from nature and by logic. ( Not geniuses , just clever kids with no drilling from our side) .
    This year we are taking them out from school to World School as we will full time travel for a year, I will observe more then.

    Looking forward to read more on your site.
    Thanks and warm regards
    Madie Dee

  2. Some thoughts about EEG and intelligence: A US EEG researcher told me he had a paper on EEG and intelligence accepted by Science, then suddenly denied publication — my advice to him was to retitle the paper as being about EEG and “performance on executive thinking tasks” or some similar term … Another US EEG researcher collected a large library of EEG records from children – I asked him if he had looked for links between EEG and intelligence. He said that to do so would be unethical because results might be misused by regressive politicians. I replied that if widely used, such a measure might (also) be responsible for some poor children (e.g.) being sent to Harvard — he said he had never thought of that! A final association: In the heyday of ‘chaotic dimension analysis’ (often applied, without proper statistical control, to almost any data) I saw an EEG experiment poster analyzing EEG and performance from groups of more and less intelligent participants (by conventional measures). Their task event-related EEG dynamics showed no significant differences (the authors were disappointed) — But some EEG measures during ‘rest’ were more sensitive ….

Leave a Reply