Simplify the following text for a Grade 13 native English-speaking person.
Original: However , his writings record the use of a wide variety of stimuli , including electric shocks , whistles , metronomes , tuning forks , and a range of visual stimuli , in addition to ringing a bell .
Simplified: However , his writings also record the use of many stimuli , including electric shocks , whistles , metronomes , tuning forks , and a range of visual stimuli .