“…The method seems to have been introduced by Heron (41) and has received explicit approval for use in learning studies by Tolman and Nyswander (123), Nyswander (87), Leeper (64), Anastasi (4), and Tryon (130). Tryon (130, p. 154) not only accepts the method, but has argued that " for such experimentally determined material as scores on successive trials in a maze, Spearman devised the method of collecting odd elements in one set, and even elements in the other set (the elements may be trials or blinds), correlating these two independent sets, and then applying the correction which eventually became known as 'Brown's formula' (sic).…”