Graphology handwriting analysis has spawned several systems. Integrative graphology focuses on strokes and their relation to personality. Graphoanalysis was the most influential system in the United States, between 1929 and 2000. The Sistema de Xandró is another method of integrative graphology. Holistic graphology is based on form, movement, and use of space. The psychogram is another method which uses specific diagrams to analyze handwriting. The Personal Worth Chart is one such method developed by the Handwriting Consultants of San Diego during the early 1980s. The psychograph is an additional psychogram method. was developed by Leslie King during the 1970s. The Wittlich
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"