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 three minutes and fifty-five seconds (3:55), "What Love Is Made Of" is an uptempo dance and house track that has been described as "rave-y" and "trance-y". Its instrumentation contains the sounds of pianos and synthesizers. Jordan Sargent of "Spin" observed that it continued the musical style first introduced in Katy's 2012 extended play (EP), "Danger EP", which was "straight-forward house". Idolator's Sam Lansky compared her performance in the song to recording artist Siobhán Donaghy. Critical response to "What Love Is Made Of" was generally positive: most critics noted Katy's vocal performance and commended its sound. Siân Rowe from "NME" was