Random generation of digits as a measure of attention: Relation to text redundancy and recall

Generation of a random series of digits appears to require more attention than a nonrandom series; thus the randomness of a series can be used to monitor attention. Instructions to recall rather than listen to passages varying in approximation to English while Ss were simultaneously generating random digits produced a significant decrement in randomness. The decrease varied inversely with the amount recalled. Recall varied positively with level of approximation. The findings suggest that more attention is being paid to the higher levels of approximation, accounting in part for the increase in recall.