Complex sentence: It was carried out by John B. Watson and his assistant Rosalie Rayner at Johns Hopkins University, and the results were first published in the February 1920 issue of the "Journal of Experimental Psychology".
Split into simpler sentences: It was carried out by John B. Watson and his assistant, Rosalie Rayner, at Johns Hopkins University. The results were first published in the February 1920 issue of the "Journal of Experimental Psychology".