Robert Merton Solow, GCIH (/ˈsoʊloʊ/; born August 23, 1924) is an American economist whose work on the theory of economic growth culminated in the exogenous growth model named after him. He is currently Emeritus Institute Professor of Economics at the Massachusetts Institute of Technology, where he has been a professor since 1949. He was awarded the John Bates Clark Medal in 1961, the Nobel Memorial Prize in Economic Sciences in 1987, and the Presidential Medal of Freedom in 2014. Four of his PhD students, George Akerlof, Joseph Stiglitz, Peter Diamond and William Nordhaus later received Nobel Memorial Prizes in Economic Sciences in their own right.