Simplify the following text for a Grade 12 native English-speaking person.
Original: Ivan Petrovich Pavlov ( 14 September 1849 â `` 27 February 1936 ) was a Russian physiologist , psychologist , and physician .
Simplified: Ivan Petrovich Pavlov ( September 14 , 1849 - February 27 , 1936 ) was a famous Russian physiologist .