Listening to one of two synchronous messages.

Abstract

Subjects were required to give verbal answers to questions coming from a loudspeaker. Occasionally two questions would start at once, one to be answered and one to be ignored. If the only clue to the message to be answered was the usual auditory call-sign, few correct answers were given; no improvement was found when the call-signs were made more distinctive. A non-auditory signal indicating which message was to be answered increased efficiency, provided that it was given before the message rather than after. The results are interpreted as showing selective discarding of information by the nervous system.