A projective personality test published by Herman Rorschach in 1921. In the test, the subject is asked to interpret abstract, symmetrical inkblots. Because the stimulus is ambiguous, the respondent must impose his or her own structure on it. In doing so, thoughts, feelings and themes, some of which are unconscious, are projected into the material. The test is particularly used for detecting the types of disordered thought patterns seen in schizophrenia and other psychotic disorders.