Study Technology, also referred to as study tech, is a teaching methodology developed by L. Ron Hubbard, founder of the Church of Scientology. Study Technology is used by Scientologists as part of their training, and is also promoted outside the church by the affiliated corporation Applied Scholastics, which presents Study Tech as a secular, universally applicable method to enhance the comprehension of any student, studying any topic. However, the method has many critics, including former teachers, claiming that the "technology" and associated schools are intrinsically linked with religious aspects of Scientology. Hubbard wrote in a Scientology policy letter in 1972 that "Study Tech is our primary bridge to Society." Most Study Tech books include a two-page biography of Hubbard that does not mention his role in creating Scientology. Religious scholar J. Gordon Melton said that Hubbard wrote the Study Tech materials to help people who joined Scientology with a low level of literacy, and that the materials are used within the Church of Scientology “not to proselytize for the religion but to teach people how to read.” Theory According to Study Tech, there are three barriers that prevent students from learning: "absence of mass", too steep a gradient, and the misunderstood word. According to Hubbard, each barrier produces a physiological response in the student such as yawning, or feeling bored or frustrated. In accordance with L. Ron Hubbard's beliefs, the method denies the existence of psychiatric conditions, or any biological learning difficulties. Harley and Kieffer (2009) stated that what they knew was Study Tech materials claim that "absence of mass" is the idea that abstractions must be illustrated physically before they can be fully understood: learning about trains is accelerated if the student can see a train or a representation of one. Scientology classrooms are equipped with modeling clay and "demo kits", small collections of everyday objects, such as corks, caps, pen tops, and paper clips. Modeling clay or the contents of such a kit are used to create a physical model of what is being studied, thereby giving the student "mass". One of the course requirements for people learning to be Scientology trainers is to model in clay the premise of every paragraph in Hubbard's book, Dianetics. Scientology classrooms are supplied with different kinds of dictionaries, and students are directed to "find your misunderstood [word]." Yawning is taken as a physical sign that a student has misunderstood a word