The human brain is a fascinating miracle of nature. Chemicals and electrical signals race around a webbed network of cells to allow us to see, hear, breathe and, most importantly, think. And we’re still figuring out exactly how it works.
One of the more peculiar behaviors of the brain is that while our ears are quite good at what they do, the control center inside our skull doesn’t fully trust them. Instead of just taking that auditory input and letting us know what we heard, the brain gets ahold of that and compares it to what we see.
In ordinary circumstances, this helps us to better understand sounds in an environment where we can’t hear quite right, like a howling windstorm or a noisy factory. But since the effect works whether we want it to or not, with the right input, our brain can be fooled into thinking it heard something it really didn’t. This brain-bending video from the BBC will have you trusting your ears even less than your brain does.