Who is the smartest out of you and your friends?
If you wanted to quickly find out the answer, how would you go about measuring it?
You might already think you know the answer but in reality, there probably isn’t a right answer. You probably know a guy or girl in your group of friends who is conventionally ‘book smart’. But how are they when it comes to creative thinking? And maybe one of your friends happens to be slightly better at math. Or slightly better at coming up with witty retorts.
In other words, there are multiple ways in which a person can be clever. There are different types of intelligence - or so it would seem. And measuring someone’s IQ is only going to give you a vague notion of how smart someone is ‘in general’.
So just what is ‘intelligence’ and what is the best indicator of someone’s overall smarts? Is there even a logical answer to this question?
One theory regarding the nature of intelligence comes from psychologist Gardner, who suggested that you could categorize smarts into different kinds of intelligence in his 1983 book Frames of Mind: The Theory of Multiple Intelligences. The theory proved popular and since then, has served as the basis for a lot of research and a lot of self-development literature.
Specifically, Gardner suggested that there might be nine different types of intelligence. Those are:
Naturalistic Intelligence – The ability to ‘connect with the wild’, to be good with animals and to be able to survive in the bold outdoors. Ray Mears is someone we might consider to have ‘naturalistic intelligence’.
Musical Intelligence – Someone with good musical intelligence will have an affinity for music, an appreciation and likely be naturally ‘gifted’ at playing instruments and whistling tunes.
Logical-Mathematical Intelligence – Someone with this kind of intelligence is your typical maths whizz, perhaps someone who is good at programming and maybe someone who works in physics.
Existential Intelligence – This intelligence is all about deep thought and reflection. If you are prone to philosophical musings and someone who has lots of thought provoking ideas, you might have good existential intelligence.
Interpersonal Intelligence – This is your ‘people skills’ or your emotional IQ. Someone with good interpersonal intelligence might be charming, or just very understanding and sympathetic.
Bodily-Kinaesthetic Intelligence - This is intelligence in movement. Good hand-eye coordination and muscle control is seated in the brain and thus it too can be considered a form of intelligence.
Linguistic Intelligence – Linguistic intelligence is verbal reasoning, reading comprehension and perhaps being gifted as a polyglot.
Intra-Personal Intelligence – Knowledge of oneself and self-control.
Spatial Intelligence – Finally, spatial intelligence refers to your ability to rotate three dimensional objects in your mind’s eye.
So, the big question is: does this theory hold up? Are there really 9 types of intelligence?
The short answer is no, not really. While the notion that intelligence isn’t as simple as an IQ score is valid, the implementation of the theory is largely arbitrary. Many of the ‘types’ of intelligence describe knowledge and personality as much as intelligence, several overlap and others are apparently missing (creativity being a big one). What is the role of memory here meanwhile? Or attention?
The more modern way to consider the nature of intelligence is to compare the ‘modular’ approach to ‘global brain connectivity’.
Those that subscribe to a modular view of intelligence look at the brain as having distinct regions, dedicated to specific tasks. For instance, we know that the motor cortex is responsible for motor movements, whereas the default mode network appears to be in charge of creative thinking and imagination.
When someone demonstrates remarkable ability in a particular aspect of intelligence, the responsible brain region tends to be larger. We know that through brain plasticity, it is possible to grow specific brain regions just like working out a muscle – but it’s also likely that there are some genetic and developmental differences that might predispose a person to certain types of thinking.
But there are not nine brain regions and their interplay is far more complex than Gardner’s theory suggests.
Moreover, there is also another factor that might have more to do with a person’s ‘general’ intelligence – which is their global brain connectivity. In other words: how well these various brain regions are connected by grey matter and how adept the ‘owner’ is at using those multiple brain regions in unison.
It turns out that the amount of neural tissue connecting disparate brain areas appears to be strongly correlated with nearly all measures of intelligence.
If we look at Einstein’s brain, then we can see evidence for both theories of intelligence. Einstein had a particularly well developed inferior parietal lobule – an area of the brain that we know to be responsible for spatial and mathematical thinking: the precise kind of thinking that might help a person to discover the general theory of relativity. Meanwhile, Einstein also struggled with verbal reasoning and appeared to have poorer performance in verbal tests. He reportedly could not speak until he was 3. On the surface, this appears to show strong specialization and support for theories of different forms of intelligence.
However, the inferior parietal lobule is also a part of the ‘association cortex’ – a network of brain regions that work together in order to help synergize information from across the brain. Einstein also showed more global connectivity, more grey matter and a thicker ‘corpus callosum’. The corpus callosum is a bundle of nerves that crosses the two hemispheres of the brain, allowing them to communicate.
In short, Einstein’s brain suggests a propensity for spatial, mathematical reasoning and a greater overall connectivity.
So, what is intelligence?
We still don’t know for sure, but our best guess is that it is a combination of factors: specific growth in useful brain regions, connectivity throughout those brain areas and a propensity for growth and learning along with the opportunity to do so.