20. Hermann Ebbinghaus
Hermann Ebbinghaus was a German psychologist who began self-experimenting despite it being taboo in the world of psychology at the time. His studies focused on the human memory and from 1879 to 1880 he conducted a self-experiment by crafting a clinical trial that revolved around 2,300 nonsensical syllables, which he committed to memory.
The purpose of using nonsensical syllables was in order to reduce the chance that he would retain the memory of the real syllables due to prior association. At the end of his experiment, he concluded that the more one has to commit to memory, the longer it takes to learn it. However, once it’s forgotten and one has to relearn the material, it is a much quicker process. Isn’t the human brain fascinating?