ABSTRACT: Conducted 10 replications of the same design in which a total of 165
Ss rapidly named series of digits presented in a focal channel (visual for Replication
I-VIII, auditory for Replication IX-X) while hearing simultaneous distracting
digits (dichotic presentation in Replication IX-X). Rate of stimulus presentation
was varied in the range from 1 trial/sec to 1 trial/4 sec. In 5 replications,
mostly those using the slower stimulus presentation rates, conflict due to distractors
was reduced when the same digit was repeated for several trials in the distractor
channel. Of these 5 replications, evidence for both perceptual filtering prior
to verbal analysis of distractor content and suppression of responses to the distractor
was obtained in 4. These and other results indicate that the nervous system may
(a) limit perceptual analysis of verbal distractor sequences that are either random
or predictable, and (b) suppress verbal responses that tend to be elicited by
predictable distractors. These perceptual-filtering and response-suppression processes
apparently function best at relatively slow stimulus input rates.