In the 19th Century, serious physicists believed that the Universe was filled with an imaginary substance called luminiferous ether, and doctors believed that illnesses were caused by smelly vapours called miasmas. Both of these scientific myths survived for over one hundred years until they were vanquished by evidence.
Myth #1: You have a lizard in your head
The idea that your mind is a battleground between passion and reason goes all the way back to Ancient Greece
- More recent neuroscience clearly shows that brains don’t evolve in layers like adding icing to an already-baked cake
- Instead, the brains of all mammals, and possibly all vertebrates, follow a single manufacturing plan
Myth #7½: You can’t grow new brain cells
This is partly true, but only in the hippocampus, which is important for learning, remembering, regulating how much you eat, and other biological functions.
- Interestingly, many other animals can regrow neurons throughout much of their brains, but we cannot. Why can’t we?
Myth #2: The left side of your brain is logical and the right side is creative
Pretty much every action you take and every experience you have is computed by neurons distributed across your whole brain.
- So it’s simply not the case that some neurons in the left hemisphere create a computer engineer and some on the right create a poet.
Mirror neurons are special cells that create empathy
In reality, they are just everyday neurons engaged in ordinary, miraculous prediction
- Your brain’s predictions begin as silent commands to move parts of your body, like adjusting your heart rate, contracting your intestines, gushing some hormones, or raising your arm
- Copies of these commands are sent to your sensory systems to become predictions of what you’ll see, hear, and feel if you move
Myth #3: Cortisol is a stress hormone, and serotonin is a happiness hormone
No hormone has just one specific psychological purpose, and all the chemicals that help create your mind work in concert
- Cortisol, for example, boosts the amount of glucose in your bloodstream to provide a quick burst of energy for your cells when your brain predicts the need, whether you feel stressed or not
- Serotonin is not a “happiness hormone,” it has many functions including regulating fat production and keeping track of energy expenditure and gaining
Your brain stores memories
Your brain reconstructs your memories on demand with electricity and chemicals
- Each time a memory is assembled, it might be built with some different neurons
- This is one reason why eyewitness testimony in legal trials can be unreliable
- Memories are highly vulnerable to reshaping
Myth #4: Your eyes see, your ears hear, and your skin feels
All of your sensations are computed in your brain, not detected in the world by your sense organs.
- You don’t see with your eyes – you see through your brain based on a combination of what’s in your head and the sense data coming from your retinas
- Likewise, you hear with your brain as it constructs sounds based only in part on sense data from your ears
- Your experiences of smell, taste, and touch are similarly constructions
Your brain reacts to events in the world
Your brain is constantly guessing what might happen in the next moment, and comparing its guesses to the sense data it receives from the outside world and inside your body.
- These guesses are the seeds that give rise to your actions and experiences.
