Littman tentatively attributed the popular imagery to Pavlovâ s contemporaries Vladimir Bekhterev and John B. Watson , until Thomas found several references that clearly said Pavlov did , indeed , use a bell . Littman tentatively attributed the popular imagery to Pavlovâ s contemporaries Vladimir Mikhailovich Bekhterev and John B. Watson , until Thomas found several references that unambiguously stated Pavlov did , indeed , use a bell .