Raven's Progressive Matrices and Vocabulary tests were originally developed for use in research into the genetic and environmental origins of cognitive ability. Raven thought that the tests commonly in use at that time were cumbersome to administer and the results difficult to interpret. Accordingly, he set about developing simple measures of the two main components of Spearman's "g": the ability to think clearly and make sense of complexity (known as eductive ability) and the ability to store and reproduce information (known as reproductive ability).