 A son of Talmud scholar Marcus Jastrow, Joseph Jastrow was the younger brother of the orientalist, Morris Jastrow, Jr. Joseph Jastrow came to Philadelphia in 1866 and received his bachelor's and master's degrees from the University of Pennsylvania.During his doctoral studies at Johns Hopkins University, Jastrow worked with C. S. Peirce on experiments in psychophysics that introduced randomization and blinding for a repeated measures design.From 1888 until his retirement in 1927, Jastrow was a professor at the University of Wisconsin–Madison, where he advised Clark L. Hull.