TEMPORAL AND SPATIAL REPETITION AVOIDANCE

An experiment is introduced in which subjects had to mark with either an ''X'' or a point 100 squares arranged in a 10 by 10 matrix randomly . One group of subjects had to proceed horizontally (starting with the top row, left to right), another group vertically (starting with the left-most column, top to bottom). Two forms of repetition avoidance we re found, temporal (avoidance of preceding choice) and spatial (avoida nce of the mark contained by the neighboring cell, i.e., the one above or the one to the left for the horizontal and vertical procedures, re spectively). Selection of a ''random'' choice in a two-dimensional arr ay is thus affected by internal (self-generated) as well as external s timuli. The two forms of avoidance were negatively intercorrelated, in dicating that suppression of internal and external cues are separate a nd mutually competing functions. Random matrix tasks may provide a sim ple means to assess a person's relative susceptibility to either form of repetition avoidance.