Often people expect I have some touching personal story about kidney disease, but it's actually the mathematics that led me to it.
When you're doing kidney transplants, you have to find out who can exchange kidneys with whom, doing blood tests to make sure it's true. You can't just work on the preliminary data. Then you have to organize the logistics.
It turns out that a Nobel is also followed by other recognitions, and perhaps the most unexpected of these is that the Japan Karate Association in Tokyo has now made me an honorary 7th-degree black belt, something that, given my athletic abilities, is even more unimaginable than being an Economic Sciences Laureate.
My Ph.D. is in operations research. I was interested in making things work better and using mathematics to help do that. So operations research is what I studied as an undergraduate and graduate student.
Maybe we could think of science as being like a nuclear chain reaction in which people and ideas bounce off each other, and if critical mass is reached, a new field is formed.
I gravitated to economics because I'm interested in how people coordinate and collaborate with each other. Economics studies all the ways people get along with each other.