Conducted 3 experiments with 90, 38, and 40 undergraduates in which Ss had to indicate by a binary motor response whether a pair of letters was in proper or reversed alphabetic order. The times required to make such decisions were (a) shorter with greater separation of the 2 letters in the alphabet, (b) shorter for letter pairs in proper order than for reversed pairs, and (c) more affected by order of the pair at small than at large separations. Decision times were also systematically related to position of the letters in the alphabet, times generally increasing from the beginning to the end of the alphabet. (PsycINFO Database Record (c) 2006 APA, all rights reserved)