Showing posts with label intellectual disabilities. Show all posts
Showing posts with label intellectual disabilities. Show all posts

Friday, February 21, 2014

Are We Getting Stupider?

As we humans grow in our scientific knowledge and our technological advancement, surely we must be getting smarter too, right?

Wrong, according to the latest genetics research, published in November 2013 in the Cell Press journal Trends in Genetics. This research claims that we may in fact be slowly but surely losing both our intellectual and emotional abilities as individuals.


How is this possible? And doesn’t this appear to fly in the face of evidence that human IQ scores are on the rise? 

The new research suggests that we are losing ground intellectually and emotionally as a result of the intricate web of genes that give us our brain power.  It turns out that this gene web is highly susceptible to mutations – changes to the basic structure of a gene – and that changes in our societal behavior has weakened our genetic selections – that these important mutations are not being selected against in our modern society. 

Do you feel like you’re under pressure?  Maybe this is why; Human intelligence and behavior require optimal functioning of a large number of genes, which requires enormous evolutionary pressures to maintain.

"The development of our intellectual abilities and the optimization of thousands of intelligence genes probably occurred in relatively non-verbal, dispersed groups of peoples before our ancestors emerged from Africa," says the papers' author, Dr. Gerald Crabtree, of Stanford University.

In other words, Crabtree believes that we were genetically at our prime hundreds or even thousands of years ago – that if a person from ancient Greece were time-transported to 2014, that person would likely give most of us a run for the money in terms of intellectual capacity.

In the long-ago early African environment, intelligence was critical for survival, and there was likely to be immense selective pressure acting on the genes required for intellectual development. These pressures would naturally result in a peak in human intelligence. From that point, it's likely that we began to slowly lose ground.


Beyond that intelligence-needed-for-survival phase, the development of agriculture and resulting urbanization made survival and health easier to acquire, which, the researchers believe, may have weakened the power of selection to weed out mutations leading to intellectual disabilities.


Based on calculations of the frequency with which deleterious mutations appear in the human genome and the assumption that 2,000 to 5,000 genes are required for intellectual ability, Dr. Crabtree estimates that within the past 3,000 years – which equates to roughly 120 generations – we have all sustained two or more mutations that are harmful to our intellectual or emotional stability.

Genes serve a multitude of purposes in our bodies. Surprisingly, recent findings from neuroscience suggest that specifically those genes that help our brains to function are the most susceptible of our genes to mutations.  This, Dr. Crabtree argues, combined with less selective pressure, is eroding our intellectual and emotional capabilities.

There is some good news in all this; the greatest concern is not for you, but for your grandchildren’s grandchildren’s grandchildren.  In other words, the intellectual slippage is extremely gradual from generation to generation. 

Judging by society's rapid pace of discovery and advancement, the researchers believe that future technologies are bound to reveal solutions to the problem. "I think we will know each of the millions of human mutations that can compromise our intellectual function and how each of these mutations interact with each other and other processes as well as environmental influences," says Dr. Crabtree. "At that time, we may be able to magically correct any mutation that has occurred in all cells of any organism at any developmental stage. Thus, the brutish process of natural selection will be unnecessary."

As long as Dr. Crabtree is right – that we will be able to identify and solve for this genetic slide into mental oblivion before we’ve become intellectual amoebas – then there’s no need for us to worry.  We can safely return to watching our favorite, mind-numbing reality television shows, knowing that we’re a good dozen-or-more generations away from seeing the consequences of our genetic laxity.


Ric Moxley
Contributing Writer