Graphology in handwriting analysis. He published his findings shortly after founding "Société Graphologique" in 1871. The most prominent of his disciples was Jules Crépieux-Jamin who rapidly published a series of books that were soon published in other languages. Starting from Michon's integrative approach, Crépieux-Jamin founded a holistic approach to graphology. Alfred Binet was convinced to conduct research into graphology from 1893 to 1907. He called it "the science of the future" despite rejection of his results by graphologists. After World War I, interest in graphology continued to spread in Europe as well as the United States. In Germany during the 1920s,
What Love Is Made Of extremely positive about "What Love Is Made Of", describing it as "darker than anything" from "On a Mission", while calling it "slinky". The reviewer went on to commend the "irresistibly pouty" chorus. Pitchfork Media's Katherine St. Asaph commented that, in the song, the singer "sound[ed] completely enthralled, by either her lover or the music" and complimented her voice, noting that it seemed "ten times bigger than before". Jordan Sargent of "Spin" magazine called the track "exuberant" and highlighted Katy's vocal performance, which he deemed "typically fantastic", while the team from pop music website Popjustice gave "What Love Is Made Of"