FactSentinel

The claim that humans only use 10% of their brain is a persistent myth with no scientific basis. Modern brain imaging technologies, including functional MRI (fMRI) and PET scans, clearly demonstrate that all parts of the brain show activity over the course of a day. While not every neuron fires simultaneously—which would actually cause a seizure—brain scans reveal that even during simple tasks, multiple areas across the entire brain are engaged. Furthermore, the brain accounts for about 2% of body weight but consumes roughly 20% of the body's energy, which would be remarkably inefficient if 90% of it sat unused.

Neurological evidence further disproves this myth. Damage to even small areas of the brain through stroke, injury, or disease typically results in measurable impairments in function, indicating that these regions serve important purposes. If 90% of the brain were truly unnecessary, such damage would have minimal effects, which is clearly not the case. Additionally, evolutionary biology suggests the brain would not maintain such an energetically expensive organ if the vast majority served no function.

This misconception likely persists because it's an appealing idea—suggesting untapped human potential—and has been perpetuated through popular media and self-help literature. In reality, humans do use their entire brain, though different regions activate for different tasks and not all neurons fire at once, which may have contributed to the misunderstanding.