Kids with high pain tolerance

I have heard of this from a family that adopted a Chinese toddler. They noticed that she didn't cry much, but they really got concerned when she got her finger pinched in a door and didn't make a peep - just stood there looking and hoping someone would get her finger out. Their theory was that in the orphanage where she had lived, crying didn't get the children any attention, so they learned not to cry. Their daughter had to basically learn to cry when she was sad or in pain. She did learn it and they are "happy" to report that she cries plenty now! Good luck!