Humans Getting Dumber

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“Human beings are getting dumber” proclaims an article in 19 February 2013. This blunt unflattering assessment of humanity is based on articles by Gerald Crabtree of Stanford University entitled “Our Fragile Intellect” published in Trends in Genetics January 2013. Crabtree lists two reasons: genetic mutations have damaged genes involved in human intellect, and evolution no longer selects for intellect. Crabtree reminds readers: “Recent human genome studies revealed that there are, per generation, about 60 new mutations per genome and about 100 heterozygous mutations per genome that are predicted to produce a loss of function, some of which are likely to affect genes involved in human intellect”. He estimates that between 2,000 and 5,000 genes contribute to human intellect, and therefore, over thousands of years, genetic mutations must have damaged some of them. Because all human races have the same intellectual capacity he surmises that the genes for human intellect were “optimised for abstract thought” during the time when the common ancestors of all human races were hunter/gatherers in Africa.

Crabtree believes the human brain, with its capacity for complex abstract thought, evolved “in our prehistoric African ancestors, well before written language and before we had the modern voice-box to produce sophisticated verbal language but after the first tools”. He writes: “Somehow the selective pressures on these ancestors led to the evolution of a brain capable of writing symphonies and performing higher mathematics, indicating that life as a hunter–gatherer was more intellectually demanding than we might think”. During this time natural selection worked in favour of intellect and emotional stability, but modern civilisation no longer exerts this evolutionary pressure. Crabtree explains with the following example: “A hunter–gatherer who did not correctly conceive a solution to providing food or shelter probably died, along with his/her progeny, whereas a modern Wall Street executive that made a similar conceptual mistake would receive a substantial bonus and be a more attractive mate. Clearly, extreme selection is a thing of the past”.

He also suggests that if people from ancient civilisations, e.g. Ancient Greece, came back to earth today they “would be among the brightest and most intellectually alive of our colleagues and companions, with a good memory, a broad range of ideas, and a clear-sighted view of important issues”. In spite of this Crabtree claims: “The sciences have come so far in the past 100 years that we can safely predict that the accelerating rate of knowledge accumulation within our intellectually robust society will lead to the solution of this potentially very difficult problem by socially and morally acceptable means”., Trends in Genetics

Editorial Comment: Crabtree is correct about mutations degrading the human genome, and therefore it is inevitable that some mutations would damage human brain function. Recent genome studies such as the 1000 Genome Project have shown that genes are being rendered useless (and therefore effectively lost) or less functional with every generation. However, no-one has reported a newly formed gene that improves human intellect (or any other human function). There is, therefore, no evidence mutations created and “optimised” these genes in any human ancestor, and caused them to evolve a large complex brain, especially as they are observed to be doing the opposite! Instead, degeneracy caused by genetic collapse (mutations) is the predictable result of taking Biblical history as reliable. Genesis tells us God created all things “very good” but the world was later ruined by human sin and God’s judgement. This means the most optimal brains ever made were the ones God created in Adam and Eve, and any mutations affecting the human brain have degraded it, not improved it.

Crabtree’s description of how natural selection could act on hunter/gatherers is also correct, but irrelevant since man started as a farmer in a prepared Garden, and faced his first survival selection pressure when he was subject to dealing with weeds and thorns after expulsion from Eden. Either way, survival pressures only serve to remind us that natural selection can only remove individuals who are less fit because they possess already less-optimal genes, and thus leave the ones who already had the optimal genes. Natural selection is never observed to create or improve any genes.

Crabtree’s assessment that human beings were smarter in the past is certainly supported by recorded human history when we look at the achievements and writings of ancient civilisations, especially when we ask: “how much could you learn, even from your mistakes, if your lifespan was 930 years, as Adam’s was?” Historical smartness and present decline is, again, exactly what would result from the Biblical history of the human race. Since Adam and Eve rebelled against God the human race has been going downhill, so it should be no surprise that the closer people were to the beginning, as in ancient civilisations, the fewer genetic mutations they would have. However, there is more to human beings than just their bodies and their genes. Genesis tells us that man was created in the image of God, and consists of body, soul and spirit. Any intellectual achievements by humans are not the results of random activity in the brain. Our minds are influenced by our relationship with our Creator, and our first parents ruined that when they disobeyed God in the beginning. Therefore, Crabtree’s optimism about us saving ourselves with science and education is wishful, but fallacious thinking. The only way we can be restored in body and mind is by the work of the Creator who made us in the first place, and came to earth as Jesus Christ, who died and rose again to restore our relationship with God. Our current earthly bodies are doomed, like this world, to continue to degenerate, but all those who put their trust in Jesus will receive a new body, including a new brain, in the new heaven and earth that God will create when this world is destroyed. Renewal of the mind can start right now for all who are transformed by faith in Christ, but will not be complete until the resurrection to eternal life with Christ. It won’t make you smarter now, but it can help you to live better in this world if you use your mind to know God’s Word and seek to live by it. (Ref. anthropology, genetics)

Evidence News 27 February 2013