Is intelligence simply a matter of how much brain we use? What accounts for I.Q., and its differences from person to person? Noted 19th century psychologist William James attempted to tackle these questions by studying savants—geniuses—and proposed that there must be underused mental potential in everyone. What else could explain why some people could perform extraordinary mental tasks and others could not?
Ever since, James’ research and quasi-metaphysical speculations have been misinterpreted and misquoted, and even wrongly attributed to figures like Albert Einstein (Robynne Boyd. “Do People Only Use Ten Percent of Their Brains?,” Scientific American, February 7, 2008).
The truth is that we “pretty much use one hundred percent of our brains,” according to PhDs Sam Wang and Sandra Aamodt, Princeton neurologists and co-authors of Welcome to Your Brain (2009). They reason, based on extensive research, that there are no “unused parts,” and that the functioning human brain is basically complete. If any part of your brain went “missing in action,” says Dr. Wang, “you would notice—and you would be sorry... or depending on which part, you might not be sorry!” Consider also that any cells or muscles not used tend to atrophy and die; and the entire brain is an active organ, using about one-fifth of the energy produced by the body.
Under normal circumstances, we use all of the “fearfully and wonderfully made” (Psalm 139:14) brain God gave us. However, many of the brain’s processes (e.g. breathing) are unconscious and work best without our awareness. In fact, abnormally high I.Q. often comes with a price, as with some cases of autism and similar neurological disorders. These disabilities occur when parts of the brain that should be active do not do their jobs correctly, while other parts—governing sensory sorting and creativity—work abnormally or without inhibition.
The real key to mental development is not how much of the brain you use, but how much and how often you use your brain! Although experience, training, injury or disability may limit our mental capacities, our real potential to learn, grow and fill the brain with useful information may be far greater than we realize—and we reach that potential by hard work and taking advantage of every opportunity. And we should not take for granted even those capacities that seem almost universal—something as basic as human speech is as complex and remarkable as creating beautiful works of art or solving complicated mathematical equations.
So, why is the “10 percent myth” so pervasive? To many, it hints at superhuman powers that could be manifested by something other than hard work! It tempts some toward magic, occultism and the like. And it encourages us to imagine how we could work powerful wonders if we could “unlock the other 90 percent.” This is not a new desire; remember the example of Simon Magus in Acts 8, who tried to buy “power” from those who seemed to have it (vv. 18–19). His sin was covetousness and idolatry, and he hoped to present himself as a god. But God calls idolatry and the works of men nothing (Isaiah 41:28–29).
Even though God performs miracles through His servants at times, they could do nothing apart from God (John 15:4–6)—and even Jesus Christ while in the flesh gave all glory to His Father in Heaven (John 5:19; 5:39–40). But God has given us a way to exceed the limits of the carnal human mind and brain—not through human effort or occult dabbling, but through the gift of God’s Holy Spirit—which connects the human spirit to wisdom inaccessible to carnal mankind (1 Corinthians 2:14).