Meeting with Nobel prize winners Amartya Sen and Kenneth Arrow , and reading the work of John Rawls , whom he met during that year , gave Professor Phelps an interest to research outside of macroeconomics . Discussions with fellow Nobel prize winners Amartya Sen and Kenneth Arrow , and especially the influence of the philosophy of John Rawls , whom he met during the year at the Center , led Phelps to undertake some research outside macroeconomics .