Are we dumber than our grandparents?

Social psychologists are tracking IQ scores and noticed a decline in the last decade after a steady rise since the 1950s. Some wonder if the recent downturn reflects genes that have been eroding all along. Are we evolving stupidity?

The concept of eroding genes—steadily but slowly marred by new slightly harmful mutations that occur every generation—has its proponents and detractors. New Scientist consultant Bob Holmes wrote, “The most controversial explanation is that rising IQ scores have been hiding a decline in our genetic potential.”¹

Holmes reviewed IQ score trends from Denmark, Japan, South Korea, Australia, Denmark, the UK, and Sweden. They show similarly rapid rises in postwar test results that peaked in the 1990s, and have steady declined since then.

Experts generally attribute the rise in IQ scores to the Flynn effect, named after University of Otago’s James Flynn. He thought that better nutrition and health, plus mental exercises that people in developed countries typically perform, would result in brighter brains and the higher IQ scores.

Holmes wrote, “If better nutrition and education have led to rising IQs, the gains should be especially large at the lower end of the range, among the children of those with the fewest advantages in their lives. Sure enough, that’s what testers usually see.”¹

But it’s looking like those gains are over.

Some researchers think the Flynn effect has been masking a steady underlying genetic erosion. Psychologist Richard Lynn of the University of Ulster, UK used IQ values from around the world to calculate that humanity has lost about 1 IQ point in the last 50 years. “In other words,” wrote Holmes, “although more people have been developing closer to their full potential, that potential has been declining.”¹

Just last year, psychologists led by Michael Woodley from Free University of Brussels linked dropping IQs to a long-term decrease in reaction time. The same nerve-cell health that enables quick physical reactions also powers quick-thinking.² And nerve-cell health can diminish as mutations mount.

Holmes cited a 2010 report in the Proceedings of the National Academy of Sciences (PNAS) by Indiana University biologist Michael Lynch that explained how most mutations are slightly harmful and can occur anywhere in the genome. If they occur in genes that brain cells use, those mutations can reduce intelligence.

In the PNAS report’s conclusion, Lynch wrote, “Thus, the preceding observations paint a rather stark picture. At least in highly industrialized societies, the impact of deleterious mutations is accumulating on a timescale that is approximately the same as that for scenarios associated with global warming—perhaps not of great concern over a span of one or two generations, but with very considerable consequences on timescales of tens of generations.”³

Decent nutrition and education may have done all the good they can for intelligence, but those factors can’t erase the accumulated mutations, let alone increase our genetic potential for greater intelligence. This preserves Lynch’s “rather stark picture” of a world population that will continue, according to Holmes, “evolving to be more stupid.”¹

Is there any way to reverse this gloomy forecast? Holmes wrote, “The only way to stop that might be to tinker with our genomes. Given our ignorance about the genetic basis of intelligence, and the ethical complexities, that is a long way off.”¹

Basically, someone would need to restore every mutation inherited from every generation. For this task, Mankind has far too little knowledge and power. It could only be done by the One who wrote the original and pristine human genome in the first place.⁴

Declining IQ scores, and the harmful mutations that likely cause them, powerfully confirm Scripture that teaches “the creation itself also will be delivered from the bondage of corruption into the glorious liberty of the children of God.”⁵

References

1. Holmes, B. Brain drain: Are we evolving stupidity? New Scientist. Posted on newscientist.com August 20, 2014, accessed August 27, 2014.
2. Woodley, M. A., J. te Nijenhuis, R. Murphy. 2013. Were the Victorians cleverer than us? The decline in general intelligence from a meta-analysis of the slowing of simple reaction time. Intelligence. 41 (6): 843-850.
3. Lynch, M. 2010. Rate, molecular spectrum, and consequences of human mutation. Proceedings of the National Academy of Sciences. 107 (3): 961-968.
4. Of course, God promises to supply those who trust in Him with a new body that is “incorruptible and undefiled and that does not fade away,” clearly implying that it will have no mutations (1 Peter 1:4).
5. Romans 8:21.

* Mr. Thomas is Science Writer at the Institute for Creation Research.

Article posted on September 19, 2014.