The project is related to magical practices and perception of their efficacy. Psychologists Paul Rozin and Carol Nemerroff demonstrated that magical beliefs/practices are based on the idea of contamination. As defined by psychologists and biologists, contamination involves transmission of a contaminated substance from a source (a person or an object), that is also "a vehicle" of this substance, to a recipient (another person or object). In some cases, contamination includes a medium that transfers a contaminated substance from the source to the recipient. This substance (essence) then becomes part of the recipient's body (Rozin, Nemeroff 1990, p. 207). Contamination activates strong emotions of disgust and fear; any contact with contaminated things, however minor, is repulsive (Bloom, 2004, p. 159). According to evolutionary psychologists, these emotions are an outcome of an evolutionary pressure that might keep us from contact with toxic substances and objects that might cause disease. Although what is disgusting is culturally determined, universally those substances that spontaneously trigger disgust are objects likely to contain infectious agents, including dead bodies, rotting foods, and bodily fluids such as feces, phlegm, vomit, blood, and semen, and it motivates proximal avoidance of such things (Tybur, Lieberman, Griskevicius 2009).