Idiot Brain by Dean Burnett Read Free Book Online

What’s going on there? Why would being taller make you more intelligent? It’s one of the weird and confusing properties of human intelligence.
    One of the more likely causes of this height–intelligence association, according to the available science, is genetic. Intelligence is known to be heritable to a certain degree. To clarify, heritability is the extent to which a property or trait of a person varies due to genetics. Something with a heritability of 1.0 means all possible variation of a trait is due to genes, and a heritability of 0.0 would mean none of the variation is genetic.
    For example, your species is purely a result of your genes, so “species” would have a heritability of 1.0. If your parents were pigs, you’ll be a pig, no matter what happens as you growand develop. There are no environmental factors that will turn a pig into a cow. By contrast, if you are currently on fire, this is purely the result of the environment, so has a heritability of 0.0. There are no genes that cause people to burst into flames; your DNA doesn’t cause you to burn constantly and produce little burning babies. However, countless properties of the brain are the result of both genes and environment.
    Intelligence itself is heritable to a surprisingly high degree; a review of the available evidence by Thomas J. Bouchard 13 suggests that in adults it’s around 0.85, although interestingly it’s only about 0.45 in children. This may seem odd; how can genes influence adult intellect more than children’s? But this is an inaccurate interpretation of what heritability means. Heritability is a measurement of the extent to which variation among groups is genetic in nature, not the extent to which genes cause something. Genes may be just as influential in determining a child’s intelligence as an adult’s, but with children it seems there are more things that can also influence intelligence. Children’s brains are still developing and learning, so there’s a lot going on that can contribute to apparent intelligence. Adult brains are more “set”; they’ve gone through the whole development and maturing process, so external factors aren’t so potent any more, so differences between individuals (who in typical societies with compulsory education will have roughly similar learning backgrounds) are more likely to be due to more internal (genetic) differences.
    All of this may giving a misleading idea about intelligence and the genes, implying it’s a far simpler and more direct arrangement than it is. Some people like to think (or hope) that there is a gene for intelligence, something that could make us smarter if it was activated or strengthened. Thisseems unlikely; just as intelligence is the sum of many different processes, so these processes are controlled by many different genes, all of which have a part to play. Wondering which gene is responsible for a trait such as intelligence is like wondering which piano key is responsible for a symphony. *
    Height is also determined by numerous factors, many of them genetic, and some scientists think that there might be a gene (or genes) that influences intelligence that also influences height, thus providing a link between being tall and being intelligent. It’s entirely possible for single genes to have multiple functions. This is known as pleiotropy.
    Another argument is that there’s no gene(s) that mediates both height and intelligence, but rather the association is due to sexual selection, because both height and intelligence are qualities in men that typically attract women. As a result, tall intelligent men would have the most sexual partners and be more able to spread their DNA through the population via their offspring, all of whom would have the genes for height and intelligence in their DNA.
    An interesting theory, but not one that is universally accepted. Firstly, it’s very biased towards men,