At first glance, it seems as though a person’s IQ would be a reasonable proxy for intelligence. The faculties tested – pattern matching, logic, spatial recognition, etc – are strong tools for grasping truths, relationships, facts, and meanings. However, viewing them as tools illuminates an important caveat: tools must be used, properly wielded, and maintained.
Now, assume that the genes and biologically relevant environmental factors that are responsible for innate intellectual capacity are effectively independent. I am neither an expert in biology nor genetics, but this seems like a reasonable assumption (see note below). Elementary statistic will show that the distribution of the product (or sum) of n normally distributed variables is normally distributed. Hello, bell curve.
However, it is one thing to assume the biological factors responsible for innate intellectual capacity are independent. It is an entirely different matter to assume that the non-biological factors of intelligence are dependent on neither the biological factors nor time, effort and accumulated knowledge!
Employing reductio ad absurdum and the Einstein as the poster-child cliché: what would Einstein have been if he was isolated at birth with no social interactions or mental exercise offered? Again, I am not an expert psychologist, but I think it is reasonable to think that he would not have amounted to much – and would probably have been insane.
Without stimulation, your mind will atrophy. With a predominance of erroneous information feeding your mind, it becomes diseased (in the abstract sense.) Having strong biological machinery may be a necessary precondition for being “very smart,” but it is certainly not a sufficient condition. I do not think I am conflating knowledge with intelligence. The ability to learn — to grasp truths, relationships, facts, and meanings — is conditioned upon an individuals existing knowledge. If things that are taken as given are erroneous, errors ensue. Errors have a tendency not only to accumulate unculled, but given intellectual path dependency, results in a higher probability of accepting more falsehoods as truths.
As intelligence is conditional upon many factors chained together, it is more gamma than Gaussian. There are far more dumb people than polite company cares to admit; there are also very few very intelligent people. Contrary to what I often prefer to think there are intellectual giants. They exist at the intersection of favorable enviroment, genetics, motivations, and opportunities. Feynman was not only smarter than I am now; he was smarter than I could potentially ever be.
Note: Some prominent geneticists have suggested that intelligence may be geographically and racially dependent. These people are usually lambasted — promptly. Even if this was found to be true, I don’t think the deviation between means would be large enough to matter.
P.S. This post was not me saying IQ tests are useless. My IQ is big. Ladies, you’ll love it.
P.P.S. I started writing this a while ago in response to a friends politically charged assertion, “Democrats are Smarter than Republicans.” Initially, this was a private email response to him. However, I became more interested in the non-political part of my response (i.e. IQ is not normally distributed.) I made my politically-oriented part — Democrats are Smarter Than Republicans — into a seperate post in an attempt to maintain the integrity of my central thesis while lessing the probabilty of Goodwin’s law asserting itself.
