Robert Yerkes was born in Breadysville, Pennsylvania (near Ivyland, Pennsylvania). Growing up on a farm in rural Pennsylvania, Robert Yerkes wanted to leave the hard life of the rural farmer and become a physician. With the financial help of an uncle, Yerkes attended Ursinus College from 1892 to 1897. Upon graduating he received an offer from Harvard University to do graduate work in Biology. Faced with a choice of Harvard or medical training in Philadelphia, he chose to go to Harvard.
At Harvard, Yerkes became interested in animal behavior, so much so that he put off further medical training to study comparative psychology. He earned his Ph.D. in the Psychology Department in 1902.