There are cases of people with no sense of pain. Here's an article about it:
http://findarticles.com/p/articles/mi_m1200/is_25_170/ai_n26713199/
...and a link to the primary it references, if you have a subscription to Nature:
http://www.nature.com/nature/journal/v444/n7121/full/nature05413.html
A relevant quote from the review:
"The team's first research subject, a 10-year-old boy, was well known in his community for street performances in which he placed knives through his arms and walked on hot coals. Despite tissue damage, he apparently felt no discomf...
Hello from the lurking shadows!
Some stats:
I've pretty much always been at least an aspiring rationalist, and I convinced myself of atheism at a pretty early age. My journey to LW started with my discovery of Aubrey de Gray in middle school and my discovery of the transhumanism movemen...
Hello, I'm an undergrad student who's been reading LW for about six months now. So far I've stuck to lurking for a couple of reasons. For one thing, most of the comments I have are already made by other people. Also, there's enough information on LW that it seems more fruitful to move on to a new article than to post a question.
There's a LOT of background reading available here on LW, which is intimidating to a new reader. I can say for myself that it's difficult to bring myself to post when I know there are dozens of background articles I still need to re...
Also, vitamins deficiency might set in at different times for adults and children. Children grow a lot, so their nutritional needs are probably different from adults.
No source, just speculation.