Proactive inhibition by mentally retarded persons: effects of distracter vocalization.

Mentally retarded adolescents were tested in eight experimental conditions using the Brown-Peterson paradigm of proactive inhibition. Length of retention interval, absence or presence of vocalization during the retention interval (naming colored lights), and rate of light presentation varied. The purpose was to determine the influence of amount of vocalization during the retention interval on retrieval from short-term memory. A filled retention interval had more a deleterious effect on retrieval than did an unfilled one, but significant amounts of memory loss occurred whether the interval was filled or unfilled. Amount of vocalization did not affect recall.