Why do some people get motion sickness while others don't?

Me and some friends were on a roadtrip the other week and, because it was a very long journey, I’d bought a book along to help pass the time. One of my friends asked me how I could read in a moving car. Apparently he can’t read in a moving vehicle because it gives him motion sickness?

So why is it that some people get motion sickness while others don’t?

I don’t know if there is a definitive answer, but I would be very interested in knowing it, if there is one. It is an interesting question to me, also.

http://www.motionsickness.net/aboutms.html

It’s thought to be caused by perceptual conflict: your body is not moving the way you expect it to based on external stimuli. As for why some people feel it and some don’t… like allergies, some people are just more sensitive than others. I think a lot more people feel sea sickness than car sickness, but the perceptual conflict is stronger at sea.

Could age have anything to do with it? When I was a kid I could comfortably read in a moving car, but now I usually can’t. Also, when I was about 12 I went on a Boy Scout trip to Anacapa Island, off Southern California, and on the boat going over, all the adults got sick but the kids were fine. Similarly, my wife and I went on a cruise about 10 years ago (I was 38), and we had no problems at all with motion sickness; but when we took one last year, we both suffered a bit, though it was a rougher voyage as well.

I think it’s more genetic than related to age. None of the people on my mom’s side of the family (myself included, unfortunately) can read in cars or be on moored boats for any length of time. I haven’t been able to concentrate on something inside a car since cI cna remember. My dad’s side doesn’t have this problem.

I have noticed that it’s gotten worse as I get older but I think that’s more due with lack of exposure to motion sickness causing activities than age. When I was a child I was always the passenger in a car and often had to ride in the rear. I also had more opportunites for outdoor boat related activites and amusement park rides. As an adult, I am almost always the driver and spend less time on the water so I’m less accomstomed to the motion.