Raven's Progressive Matrices (often referred to simply as Raven's Matrices) are non-verbal multiple choice measures of the reasoning (or, better, "meaning-making") component of Spearman's g, which is often referred to as general intelligence. The tests were originally developed by John C. Raven in 1936. In each test item, the subject is asked to identify the missing element that completes a pattern. Many patterns are presented in the form of a 4x4, 3x3, or 2x2 matrix, giving the test its name.