We Use Only 10% of Our Brains and Evolution Is Just a Theory

Nonsense is prevalent but you don't have to buy into it.

Posted Dec 05, 2014

Myth: Humans use only 10% of their brains.

Fact: Functional neuroimaging studies have revealed that we use most of our brain, only not all at once. A fair analogy to explain brain activity is the use of electricity in a house.  A house pulls a certain amount of energy just for baseline operation to power things like plugged in smoke detectors, lamps, chargers, clocks, cordless phones, etc.  Moreover, if a few lights, a computer, a TV, and a charging cell phone are drawing energy from the grid, only a small percentage of the house's full capacity is in use. But if the air conditioner, washer and dryer, refrigerator compressor, many lights, several appliances and various devices are also on, then a lot more of the house's full energy potential would be in use. Thus, it wouldn't be accurate to say we use only 10% of our houses' electrical potential.  We just don't usually have everything running all at the same time.

Similarly, a fair amount of metabolic energy is used by several brain regions just to keep basic life support going (i.e., essential functions like blood pressure, heart rate, digestion, waste formation, etc.). Now add to that all the brain activity occuring when a person is doing even someting simple like taking an audio tour at a museum.  Their auditory cortex is processing the sound of the narrative being listened to; their visual cortex is processing the images; their frontal lobes and convergence zones are interpreting all the verbal and sensory input; other neocortical structures are producing cogntive events like interpreting and evaluating the information; their limbic system is contributing to emotional responses; their motor cortex is producing movement; their somatosensory cortex is processing various external and internal sensory data (e.g., ambient sound, other sights, temperature, smells, internal body sensations, spacial orientation, etc.).  Seems like a lot of activity, right?

In fact, despite weighing only about 2% of our body weight, our brains consume over 20% of all our calories.  What's more, it is extremely unlikely that evolution would have led to an adaptation that is so dangerous and inefficient. The size of our big brains is a serious liability for both maternal and neonatal birth survival, and infants are utterly defenseless for many years after birth while their already big brains continue to grow and develop. Therefore, it its hard to believe that evolution would equip us with big, dangerous, metabolically expensive, mostly unused brains.  And, as noted above, current neuroscience indicates that it didn't.

Myth: Evolution is only a theory.

Fact: Evolution is an incontrovertible fact of nature despite being referred to as only a "theory." The confusion arises because when used in a non-scientific context the word "theory" implies that something is unproven. But when used in a scientific context, a theory is an explanatory framework based on observation, experimentation, and replication of results which helps in understanding and predicting phenomena.

Just as we have "a theory of evolution," we also have "a theory of gravity." But few would argue that gravity is only a guess or insist that some alternative explanation for the myriad phenomena it predicts and explains is more credible. (Like "intelligent design" has been proffered as an alternative to evolution; see footnote below.) Evolution is a fact like gravity. And while we may refer to them as "theories," they are not guesses, unproven or speculative.

Hence, ignore or deny the theory of gravity at your peril and deny the theory of evolution if it's your "truth" to do so. But keep in mind that "truth" changes while facts remain.

Remember, for thousands of years people were speaking the "truth" when they stated that the Earth was flat and that all celestial bodies revolved around it. Now we know the facts and they are not likely to change.  In fact, Pope Francis himself recently declared that the big bang and evolution are real.  He just believes they are not incompatibe with creationism stating "God is not a wizard or magician."  In other words, the Pope himself stated that whatever got the universe going did so 13.7 billion years ago and humans likely evolved from ancestral progenitors.

Thus the idea of strict, Biblical literalism - i.e., the Earth was created in six days appproximately 6500 years ago when the first humans were created into Eden - has been called into question by the absolute leader of the Catholic Church. Hence, while the "truth" of Catholicism's central dogma has just changed for almost one billion Catholics, the facts [of physics, cosmology and evolution] remain unchanged.

Footnote: "Intelligent design" is not science. In fact, it's the exact opposite of science because it starts with a conclusion and then works backwards to "prove" its theory. Science starts with hypotheses or observations, conducts experiments, makes measurements, collects data and then endeavors to build a theory (an explanatory and predictive model) for what was observed or measured. Hence, scientific theories are constantly changing to incorporate new data. Indeed, the best science tries to disprove its theories and hypotheses rather than fit the facts to its ideas. So, unless a theory is testable, potentially falsifiable, and its data are reproducible, it simply is not science. Thus intelligent design is not science since it meets none of these criteria and is, therefore, better categorized as philosophy, theology or religion.

Remember: Think well, act well, feel well, be well!

Copyright by Clifford N. Lazarus, Ph.D.