Everyone is made up of the same matter; most humans have the same anatomy – 2 hands, 2 legs, 1 head, etc. Layouts are roughly the same. But, the more you zoom in, the more differences you find. We have differently-sized palms, we have different eyebrows, lips, noses, etc.
So why are we unique if we have the same brain and body?
The answer lies in how much you are willing to zoom-in into the brain or someone’s mental capacity to draw comparisons.
While it is true that most of us have roughly the same brain structure, there is a whole lotta difference at the finer level of neural connections and neural density. This difference is an “accumulated difference” from all of our experiences, past learning, stress from the environment, and even the order in which we learned things and used them professionally. The form of our brain is genetically determined in its rough structure but dependent on the environment for finer differences.
We, individuals, have many differences. 80 billion neurons – each with 100s of 1000s of connections to other neurons. The way these neurons are connected changes how the brain functions. Due to minute changes in how our genes organize the cells in our bodies, the ever-changing environment, and differences in our experiences, these 80 billion neurons have small differences in how they connect to each other. These individual differences exist.
Differences in intelligence
Researchers have looked at intelligence from just about every angle – genetic, adaptation and evolution, theoretical models, arrangement of neurons, cell structure, life experience, etc. From our personal uniqueness point of view, Howard Gardner’s 8 intelligence types is useful. He defines intelligence as “biopsychological potential to process information that can be activated in a cultural setting to solve problems or create products that are of value in a culture.
His 8 types are:
- Visuo-spatial intelligence – Describes sophistication in visualizing and arranging information in a mental map.
- Naturalist intelligence – Describes an understanding of nature and life forms
- Bodily-kinesthetic intelligence – Describes a deep understanding of movement, body positions, coordination, dance, sports, etc.
- Musical intelligence – Describes an intuitive understanding of sounds, rhythm, voice, etc.
- Linguistic intelligence – Describes language skills and comprehension
- Intra-personal intelligence – Describes personal insight, self-reflection, self-awareness, etc.
- Interpersonal intelligence – Describes social and emotional intelligence regarding relationships, culture, communities, etc.
- Logical-mathematical intelligence – Describes scientific thinking, liking of numbers and theories, etc.
These intelligences are not just cultivated, they are partly inherited through biology. During a child’s growth, society observes these and encourages them to build skills in some areas. So a small bump in 1 type of intelligence becomes a specialized intelligence in the future. Similarly, there could be high intelligence in all 8 domains but only a few are encouraged in schools and at home, so over time, a child acquired specialized skills in just 1 or 2 domains. It’s predisposition + lifelong developments that create unique differences in intelligence.
Regardless of IQ scores, one study on 1000+ 12 to 16-year-old school children saw there was a huge diversity in all types of intelligence and most students (low and high IQ) had more than 2 types of intelligence. But only logical-mathematical, music, and visuo-spatial intelligence correlated with IQ. Students had other forms of intelligence unrelated to IQ, but more often than not, schools and society don’t encourage honing those other forms of intelligence. That’s an opportunity for developing unique intelligence in children.
The main finding here is that children had multiple types of intelligence simultaneously, which means they also had unique combinations of intelligence, making them as students, more unique.
Fluid vs. Crystalized intelligence
Let’s now simplify this. Another approach to individual differences in intelligence is to look at crystallized and fluid intelligence. Crystalized intelligence is past learning and Fluid intelligence is the brain’s processing power in a particular situation.
All 8 domains could technically improve crystallized intelligence if someone builds skills and specializations.
Fluid intelligence is very interesting because researchers know we have cognitive processes like memory, attention, perception, and decision-making working together. But where is the “core” intelligence here? One point of view, which I personally think fits the world as we know it, is that our ability to break down problems into small chunks and then combat big problems is a form of intelligence in itself. Here’s an example. You are new at your college and you’ve been given a new assignment on a topic you’ve never studied before. Will you have the capacity to break down that new topic into small manageable parts and conquer it, or the whole thing has to make sense from the very start?
One study suggests our ability to make micro-decisions and break down a complex task into small sub-tasks is our “fluid intelligence”. It uses attention, memory, working memory, critical assessment, etc., together. Why should this be the case? Researchers argue that high fluid intelligence can manage more complex sub-tasks. And low fluid intelligence makes it harder to manage complex sub-tasks even if they are small tasks. Fluidity in intelligence is proportional to the complexity of a small task that one can handle.
This is where humans get more interesting. Breaking down a task into small units is a skill we acquire since birth. We develop this skill differently based on how we are challenged, what we are exposed to, what we are encouraged to do, etc., So our fluid intelligence itself becomes diverse and unique. And on top of that, all our life experience adds to more variation in crystallized intelligence.
It is also very easy to say we are similar to chimps and yet we have the internet and they don’t. It’s about how detailed a picture you are looking at to see the differences. Humans and chimps have about a 95% similarity in genetic coding. Humans on average, from any race and place, are 99.9% similar. You can read more about genetic variation here.
But that ain’t the main thing. Humans are plastic and developmental beings. That means we change over our lifespan. Many of our traits and capacities are ephemeral. We change how we think, how well we think, how our brain is organized, etc.
Neural connections change based on what we learn. There are massive differences between some regions for musicians and non-musicians, professional taxi drivers, and direction-void people like me.
Neural changes have a 2-way channel with mental capacities. Just like mental capacities have a 2-way channel with neural changes. One affects the other in both directions.
Some cultures have different ways of conceptualizing ideas and have different words for them. The Kuuk Thaayorre people from Pormpuraaw (west of Cape York) don’t have words for left and right. They always speak in terms of north, south, east, and west. They even locate objects based on these directions. For example, they can point to a rock and say it is northwest of me. This cultural quirk has positively affected their direction orientation and spatial reasoning, making them better than us – we, the traditional ‘left-right’ people.
Another example of a debated phenomenon is the extensive vocabulary the Inuits have for snow. Turns out they have many different words and this may be due to the dominance of snow in their area which has conditioned their senses to perceive subtle differences. Here is a detailed account of it. Most of us from non-snowy regions call all things white, soft and falling from the sky snow.
These differences further affect one’s readiness to assess something ‘intelligently.’ One isn’t stupid if one can’t differentiate between multiple types of snow. The context matters. Similarly, one isn’t more intelligent because one can recognize everyone’s voices perfectly. Such differences are abundant. And there are transfer effects (a skill in one domain helping in a different domain) in noticing changes that could contribute to higher or lower IQ.
These factors contribute to what we call intelligence. Now IQ is not intelligence. What people often misunderstand is that IQ is a number that correlates with many abilities that predict intelligence – verbal ability, attention span, memory, etc.
IQs are roughly stable but one cannot say that IQ is hardcoded in us. Early experiences that help build memory or train your attention span can affect IQ in the future. So human experiences and their biology, both contribute to IQ.
IQs follow the normal distribution where the human average is an IQ of 100 (by design). 99.9
Now, how someone uses their cognitive capacity to function in life is further affected by their motivation to do so – by their readiness to do well, their confidence in their own ability, etc. This may not guarantee neural changes over a short term but it can affect the IQ score.
Add a layer of expectations and confidence to real-life differences in intelligence. Let’s take memory as an example. Your confidence in what you can remember or not, affects what you actually remember. And, other people’s expectations affect how well you perform in school. (it’s called the Pygmalion effect)
Motivation during an IQ is very well documented, and we see 1 trend – motivation determines the IQ score. On average, trying hard to do well in an IQ test and getting incentivized to take the IQ test can bump your score by 10 points. Researchers propose that the value of IQ reduces in predicting achievement and success once you consider how much motivation affects the score.
This is a crazy opportunity for individual differences to arise.
Do you see why it is so easy for people to have different IQs, different personalities, different skills, etc. even though we all roughly have the same brain structure?
A lot of it depends on your choices while you are alive. You are uniquely intelligent. That’s probably the best way I can put it and that isn’t political correctness.
P.S. I have something more for you if you liked this article. Have you wondered if you are weird or normal? You’ll find your answer here.
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Hey! Thank you for reading; hope you enjoyed the article. I run Cognition Today to paint a holistic picture of psychology. My content here is referenced and featured in NY Times, Forbes, CNET, Entrepreneur, Lifehacker, 10-15 books, academic courses, and research papers.
I’m a full-time psychology blogger, part-time Edtech and cyberpsychology consultant, guitar trainer, and also overtime impostor. I’ve studied at NIMHANS Bangalore (positive psychology), Savitribai Phule Pune University (clinical psychology), and IIM Ahmedabad (marketing psychology).
I’m based in Pune, India. Love sci-fi, horror media; Love rock, metal, synthwave, and pop music; can’t whistle; can play 2 guitars at a time.