Myth 1: Blood is blue in your body
A widely shared myth is that blood is blue until it is exposed to air or replenishes its oxygen.
Because veins are a greenish blue, that theory sounds reasonable enough.
But the fact is, human blood looks the same in your body as outside: red.
That hue is brighter when it’s oxygen-rich and darker when it needs that oxygen replenished, but it’s red all the same.
The tissue covering your veins affects how the light is absorbed and scattered, which is why the blood circulating your body looks blue.
Myth 2: Humans only use 10 percent of their brains
The idea of unlocking hidden brain power might make a compelling storyline for a movie, but it simply wouldn’t happen in real life.
One fact playing into the myth is that 90 percent of brain cells are “white matter” that help neurons survive, and only ten percent is the “grey matter” of neurons in charge of thinking.
But that white matter could never be used for brain power, so claiming 90 percent of our brain is wasted is like saying you waste peanuts when you throw out the shells.
Any MRI scan will show you that even saying a few words lights up way more than ten percent of your brain.
Scientists haven’t uncovered any area of the brain (much less 90 percent) that doesn’t affect thought, movement, or emotion in some capacity.
Myth 3: Neanderthals were a less evolved human ancestor
First of all, let’s get one thing straight: Neanderthals aren’t ancestors to modern humans.
The two species lived at the same time, mostly in different areas of the globe.
When the species did cross paths, there’s even evidence that they interbred.
But evidence doesn’t suggest they were cognitively inferior to humans.
Fossils show Neanderthals made tools, used fire, cleaned their teeth, ate medicinal plants, buried their dead, and maybe even cared for their sick and wounded.
Scientists no longer think Homo sapiens wiped out their Neanderthal cousins.
Neanderthals likely were already dying out as the climate changed, while modern humans’ trade networks, diverse diets, and innovative tools helped them survive.