1.7: Biological Psychology Myths

As complex as the brain is, naturally misconceptions make their way into popular culture. It’s valuable to address these myths about neuroscience and explain the evidence that refutes these statements .

“We only use 10% of our brain.”

This wildly-inaccurate statistic has been the foundation for several fictional movies, TV shows, and books. The truth is that we use every part of the brain, and most of our brain is active most of the time – just not at the same time. Neurologist V.S. Ramachandran uses a great analogy to describe the fallacy of this myth: does a traffic light only use 33% of its lights?

A properly functioning traffic light will use all three lights at very precise times. The activity of the brain is closely regulated by multiple mechanisms which prevent unusual electrical activity. In fact, if too many cells were active at the wrong times, just like a traffic light showing both green and red, chaos ensues – one cause of seizures is excessive neural activity.

“Forming memories causes new neurons to be born.”

Another misconception is the idea that each new cell in our brain represents a new memory. While we are far from understanding the process of exactly how memories are formed in the brain, we do have a few clues. Most likely, memories are stored at the sites of close contact between neurons, called synapses. Changes in in ways neurons connect and communicate with one another is likely the mechanism behind how memories are formed and stored, rather than the creation of new neurons.

Even though the process of cell reproduction is halted in the majority of adult neurons, we are still capable of new neuronal growth, a process called neurogenesis. A few brain areas in particular, like the hippocampus (used in learning and memory functions) and the olfactory epithelium (used for smelling), do exhibit frequent birth and death of new neurons.

“The brain cannot repair itself.”

If neurons aren’t being replaced in adulthood, then how do people spontaneously recover from neurological injuries like a stroke?

One of the most amazing features of the brain is the phenomenon of plasticity, the ability to change over time. Even if critical brain areas are damaged, it is theorized that the brain learns how to “rewire itself,” essentially figuring out how to carry out these functions without using the damaged connections.

Unfortunately, there are some conditions that are neurodegenerative, meaning that their symptoms get progressively worse over time. Many of these disorders, like Parkinson’s disease and Alzheimer’s disease, currently don’t have any simple cures or treatments that don’t carry risks and side effects. For people with these conditions, there isn’t strong evidence that the brain can recover from the destruction from these diseases.

Fascinatingly, we do have one strange quirk about signaling between the brain and the rest of the body: signaling pathways from the left brain crosses over to communicate with the right half of the body, and vice versa. This contralateral organization is an unintended consequence o f evolution, and is one of the major distinguishing features of the vertebrate brain.

“If you are analytical, you are left brain dominant, but if you are creative, you are right brain dominant.”

A common misconception is that the two hemispheres of the brain are responsible for wildly different functions. The truth is that nearly every function that the left half of the brain can do, the right half can do just as well, and vice versa. Sensory information, voluntary control of the muscles, memories, and many other behaviors can be performed equally well by both the left and right halves of the brain.

A major exception to the “left vs. right” component is the processing and production of language. For some reason unknown to scientists, these functions are heavily lateralized in the left hemisphere for most people.