I love seeing science become mainstream and cool, but sometimes “pop-sci” borders on pseudoscience and becomes an entirely different beast. There are certain myths and themes that crop up across the internet as well as in movies and conversations that just plain bother me because they are so completely unfounded in truth. Today’s post is a rant against one of the worst.
The “10% of Our Brains” Myth
This is one of the worst offenders I know. It has cropped up in movies like Wedding Crashers and Limitless, even on TV shows like Stargate SG-1, and every once in a while gets brought up in conversation. The myth goes something like this:
We only use 10% of our brains; if we could use the other 90% we’d be much more capable!
What, I wonder, do proponents of this myth believe the other 90% of our brain is doing? Just sitting idly by? Do they propose that there is no electrical charge going through it, that the neurons are effectively dead?
It is true that not every neuron in the brain is firing at any given moment, but this hardly means that we do not use those neurons. It would make no sense for every single part of your brain to be active every single moment. Like a computer, the way the brain functions is to activate parts “as needed” (to over simplify matters). I believe what spreaders of this myth are referring to is the fact that much of our brain does not directly/obviously contribute to a conscious decision making process.
Here’s the truth: the human brain evolved in stages and can be broken into three distinct layers. The first two are commonly called the reptilian and mammalian brain. Reptiles have only the first, mammals both. Finally, humans have a third layer stacked atop both called the neo-cortex. This progressive (stacked) organization shows us how our species evolved over time.
It is true that the neo-cortex is responsible for much of what we consider higher-thought and consciousness. However it would be a gross over-simplification to say the other parts are not used. These more “basic” parts of our brain are responsible for maintaining homeostasis and sub-conscious functions, for example. They make sure that we keep breathing when we’re not actually thinking about it, that our body temperature stays regulated, and so on. In other words, these parts keep us alive.
Maybe the myth is lamenting the fact that we need to use a portion of our brain for such tasks. However, emotional systems are built into these parts of the brain. As Malcom Gladwell points out in the book Blink: The Power of Thinking Without Thinking, these systems still perform an important role in the decision making process. He calls it “thinking without thinking” and he is right – these parts of the brain (which contribute emotional and other content) make important contributions to our conscious thoughts.
“Conscious thought” is clearly a phenomenon which we do not entirely understand, but one thing is clear: many subtle factors contribute to it. Another one of the primary responsibilities of the “lower parts” of the brain is processing incoming sensory data (sight, sound, smell, etc.). Some of the more respected theories about human conscious thought suggest that it came about (partially) as a byproduct of there being enough space in the brain for all of the data from these lower-order systems to interact (I highly recommend the book Big Brain: The Origins and Future of Human Intelligence if you are interested in the neuroscience here). From this perspective, sensory data is not just a connection to the outside world – it is the very stuff upon which human consciousness is built! Clearly we need these lower systems to operate not just to maintain the health of our bodies but to provide the fundamental data that allows us to think in the first place.
Have you heard this myth before? Do you know of any bad pseudo-science offenders? Let me know below!