After his two years teaching, he married Bertha Lutzi with very little money. [ 3 ] After marrying Bertha Iutzi, they both began attending the University of Michigan . [ 3 ] [ 4 ] Here he began his formal study of psychology and graduated with his bachelor's degree in 1913. [ 3 ] [ 4 ] After teaching in Kentucky, Hull accepted a teaching assistant position at the University of Wisconsin under Joseph Jastrow in order to join their graduate program. [ 3 ] [ 5 ] While taking classes and working, he privately worked on research based on the evolution of concepts, which he later applied to his dissertation, "Quantitative Aspects of the Evolution of Concepts." [ 3 ] [ 4 ] [ 5 ] After graduating, he spent some time working as a half-time assistant and eventually teaching as a full-time instructor at the University of Wisconsin before moving on to Yale. [ 3 ] [ 4 ] [ 5 ]