[amalia (OP)]

Ema worte to us with an interesting question:
Why do some of us experience fear of heights? And what happens in the brain when it happens?
Do you know the answer?

[alancalverd]

The fear is not generally of height itself, but of a perceptible edge that you can fall off. I haven't met anyone who was afraid of standing on a hill 1000 ft above sea level in the middle of England, but plenty of people dislike being near the edge of a 100 foot cliff at the coast or the Yorkshire moors.

I've flown passengers in hot air balloons, where my wife once remarked "The basket feels about 8 feet high when you try to climb into it, but as the balloon rises, the walls get smaller and at 10,000 ft everyone is huddled in the middle, trying not to trip over that little 6 inch fence around us." But the same passengers were perfectly relaxed when strapped into the seat of a glider, presumably because there was no possibility of tripping and falling out.

Despite flying all sorts of things to all sorts of heights with no concern, I dislike standing on tall ladders, but I'm perfectly happy to sit on a decorator's platform to paint the ceiling.

[evan_au]

This is an innate reflex which even young infants respect. Start at T=30seconds...

It should be fairly easy to study - I have seen adults freeze when using VR helmets showing a visual cliff.
Now, if only we had an MRI-safe VR headset.
The person in the MRI scanner can't move their head during the scan, but it would be easy to repeatedly show a scene walking up to a cliff. Human binocular vision can provide good cues about the surface you are walking upon.