Perception and Retention of Verbal Information Presented during Auditory Shadowing

Nine subjects listened through one earphone of a binaural headset to 50-word lists of common English words read to them at a rate of two words per second. They repeated the words that they heard while listening for an occasional word that might or might not be presented on the other earphone. This word, should it appear, was to be remembered until the conclusion of the 50-word list, at which time it was to be recalled. No more than three target words were presented with any one 50-word list for shadowing. The results indicate that shadowing performance is almost totally disrupted at the point of insertion of the target word, whether the target word is finally correctly remembered or not. Memory for the target word deteriorates as some function of the time between presentation and recall. Since time between presentation and recall and amount of intervening material between presentation and recall are directly correlated, it is impossible to say with certainty that the recall data support a decaying-trace theory of immediate memory or an interference-type theory. The results of a similar study using visual target words are cited to lend support to the position that an interference-type theory is to be preferred in this case. Finally, these data further confirm the validity of the concept that man's perceptual system is basically a single-channel one with a limited information-handling capacity.