Before we continue, it is important you can distinguish between the two different types of intelligence.
- Crystallized Intelligence
- Fluid Intelligence
Crystallized Intelligence refers to the knowledge and skill one accumulates over their lifetime. For example, being able to point out the Atlantic Ocean on a map, or knowing the meaning of the word “Mercenary” represent crystallized knowledge. Your accumulation of general facts and knowledge represent your crystallized intelligence. This is not the type of intelligence IQ tests focus on.
Fluid Intelligence has been defined in many different ways. But to be put simply, it refers to one’s ability to understand and reach valid conclusions based on new information. Another way to think of fluid intelligence is one’s capacity to understand and solve a novel problem. This is the type of intelligence IQ tests measure.
However, Fluid Intelligence does rely on Crystallized Intelligence. Take the work associated problem:
Vindictive is to Revenge, as Mercenary is to __________ Answer: Money
If you don’t know the meaning of the words, Vindictive, Revenge, and Mercenary, (examples of crystallized intelligence) you can’t solve the problem. Being able to determine the relationship between these words tests your Fluid Intelligence. Vindictive people get Revenge, Mercenaries get Money.
There Are Many Theories on Intelligence
What you’ve read so far represents the most basic definition of intelligence. The truth is there are many theories which try to narrow down the definition of intelligence. By understanding the merit and flaws in these theories, we can gain insight into how intelligence works in the human brain and what we can do to improve it.
- Theory of Multiple Intelligence (Howard Gardner)
- Two Factor Theory of Intelligence (Charles Spearman)
- Working Memory Theory of Intelligence
- Abstraction Reasoning Theory of Intelligence
Theory of Multiple Intelligences
This theory is broken intelligence down into a number of different components including, logico-mathematical, linguistic, spatial, musical, kinesthetic, interpersonal, and intrapersonal. Gardner argues that IQ tests only measure the spatial, linguistic, and logical components of intelligence. Many people criticize his theory because it has never been tested or subjected to peer review. Others point out evidence of strong correlations between many of his categories of intelligence, suggesting there is an underlying factor.
Two Factor Theory of Intelligence
This theory proposes all intellectual abilities are comprised of two factors. This theory states there are separate categories of intellectual ability similar to the Multiple Intelligence Theory called ‘S’ factors, but there is also an underlying general intelligence factor which affects all those categories called ‘G’ factor.
While the existence of a ‘G’ factor is a statistical regularity and isn’t being debated, scientists have yet to agree on the exact neuroscience cause behind it. The ‘G’ factor is closely linked to one’s ability to learn novel material and understand complex concepts. IQ tests are frequently used to estimate an individual’s ‘G’ factor. Genetics are thought to account for 40-80% of the ‘G’ factor. Brain size and cortical thickness share a moderate correlation.
Working Memory Theory
Working memory refers to the system in a brain which provides temporary storage and manipulation of information necessary for complex tasks such as language comprehension, learning, and reasoning. Having a greater working memory allows you to hold and manipulate a greater amount of information in your head for longer periods of time.
Some scientists theorize that one’s working memory capacity is almost identical to the “G” factor, identified in the two-factor theory. Some studies have found their correlation to be identical, while others have found the correlation to be lower.
Abstract Reasoning Theory
Abstraction is defined as a process by which higher concepts are derived from the usage and classification of “real” or “concrete examples. Another way to think of abstractions are the similarities which exist between multiple examples.
To better understand this, let’s turn to the word problem from earlier.
Vindictive is to Revenge, as Mercenary is to __________ Answer: Money
The abstraction here is “the “want” or goal” of the first word. By recognizing vindictive people want to get revenge, you can determine Mercenaries want money. Simply put, abstract reasoning refers to one’s ability to recognize these types of similarities between concrete examples. You “abstract” or identify the most relevant similarities between events.
Some scientists argue abstract reasoning is primarily responsible for the ‘G’ factor as there is a very high correlation between the two.
Criticisms of the ‘G’ Factor
The most well-known criticism of the ‘G’ factor was presented by the biologist Stephen Jay Gould. He suggested the ‘G’ factor is a fallacy. That it isn’t a physical thing in the brain, but simply a product of statistical calculations. In other words, scientists treat the ‘G’ factor as a concrete thing, when it isn’t a concrete thing, but merely an idea.
What Does All of This Mean?
Statistically speaking, there is an underlying factor (‘G’ factor or IQ) which accounts for a large percentage of one’s capacity to understand and solve novel problems. However, Stephen Jay Gould’s criticism holds some weight. Scientists pruning the brain for a root cause such as working memory or abstract reasoning are likely to come up empty-handed.
Without a doubt, the ‘G’ factor is a culmination of many different processes in our brain. Some processes may even be more important, depending on the person. Recently, scientists have identified many different ways to improve not just your ‘G’ factor but cognitive processes such as memory and focus.
We now know the human brain is comparable to any muscle in our body. We can grow and strengthen our brain through use. 1 The problem is, not many people know how to properly grow their brain. There are many constraints which can slow or even reverse brain growth, and there are variables which can be harnessed to accelerate brain growth. Furthermore, you should target and grow the most important areas.
Do Genetics or Your Environment Determine How Intelligent You Are?
The nature vs. nurture debate on intelligence used to be a big issue. Scientists were trying to answer the questions, Do genetics determine one’s intelligence? Does the environment determine one’s intelligence? Or is it a combination of the two? And if it is a combination, does one’s genetics or one’s environment play a bigger role?
There are two things we do know for sure. First, genetics do play in role in one’s intelligence. Genome-wide association studies, which can complete sets of DNA for variation, have confirmed this. 1 Scientists have identified at least 20 genetic variants associated with intelligence, estimating each accounts for under 1% of variation between IQ scores. 2
Second, one’s environment also plays a role in their intelligence. For example, when oppressed Tibetan and Chinese ethnic minorities are brought to Canada and the United States at an early age, their IQs skyrocket 20-30 points over their oppressed, but genetically similar counterparts. 3
We know that intelligence is a combination of one’s genetics and environment, but which contributes more?
Many studies have been conducted in an attempt to answer these questions, and the answer is different every time. One study concluded that intelligence is 50% heritable, while another concluded 80%. 5 But there is an innate flaw in types of studies which try to pinpoint an exact number. There is no exact number.
You can decrease the heritability of any trait by increasing environmental variation. Variance in environmental factors will modify differences in performance, and show the environment had a large effect on the trait being studied. Alternatively, if everyone is subjected to the same environment, the differences in the trait would be attributed to genetics. In short, the heritability of any trait depends on environmental variation.
Don’t be bothered by the absence of an exact number. What’s important is that the environment does play a huge role in the determination of one’s cognitive abilities. Genetics determine our intellectual potential, and our environment determined whether we reach that potential.
How many people do you think ever achieve their full genetic potential?
The sad truth is, virtually no one lives up to their full genetic potential. Most people don’t know they can improve their cognitive abilities, don’t care about improving them, or don’t know how.
If you are on this site, chances are you already care. But many are skeptical, and reluctant to believe they can enhance their IQ, memory, focus, and capacity to learn. The truth is this, your brain is comparable to any muscle in your body. You can strengthen it, and improve all your cognitive abilities.
- Garlick, Dennis. Intelligence and the Brain: Solving the Mystery of Why People Differ in IQ and How a Child Can Be a Genius. Burbank, CA: AESOP, 2010. Print.