How does our vision stay steady when moving?

06 September 2016


How does our vision remain steady even when we are moving?


We eyed up Andrew Holding for an answer to this...

Andrew - I went and look this up just a bit earlier and there's kind of two ways of dealing with this problem and actually, they're both mentioned in the question. If you're a camera nerd, you may have come across two ideas - optical stabilisation and digital stabilisation. So the first one, optical stabilisation is the idea that the camera has something in it that means the lenses and the sensor all move as you move along. That kind of takes a bump out so we see them with steady cams where you have these big rigs. So when the guy walks forward, the whole camera stays still.

Kat - So this is kind of like suspension for a camera.

Andrew - Well, your whole head can do that to something. Your eyes can stay fixed on a single location and you can move your head around. So, if you take a bird of prey and you have it on your room, if you move a bird of prey on your room, its head stays absolutely still. It's quite hilarious because you can move around really quite viciously and the head will stay exactly still.

Kat - They're just like locked on.

Andrew - Yeah. Eventually, the bird of prey will get annoyed and fly off.

Kat - And peck your own eyes out or something like that.

Andrew - And then the other half is this idea of distal stabilisation. So the way a digital camera does that is it takes a bigger picture than it needs. And then as the image moves around, it centres on the same point and just throws away the external information it doesn't need. And your brain can do that slightly differently because you've got your ears turning about motion. So as the image moves around, your brain sort of says, "Well, I know it's not really moving." Of course, the problem with that is if you're in a car and you're not look at where you're going, your ears and your eyes are telling different things. Your brain goes, "There's only one thing that can be happening right now unless I've been poisoned." Because evolution hasn't yet caught up with the invention of cars and that's why we then get really sick.

Kat - Does anyone else get travel sick?

Andrew - My daughter gets very travel sick.

Kat - It's the worst. I just got worse and worse, and worse as I got older. So it's like, "Are my ears and my eyes getting worse?" And then talking to each other less.

Andrew - So, there is a thing that, as you get older, you get more dizzy. So, if you're a young kid and you're on a roundabout, you can do that and go around, around, around and walk off and it's hilarious. You do it when you're in your 30s and suddenly, you'll feel really ill. I've never heard of people doing it in their 60s. maybe there's people out there who are still able to do it and still getting strong.

Kat - If any of our listeners, please do it safely. If you would like to put your elderly relatives on a roundabout and report back and compare them with younger children that would be really great or maybe not.

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