Irrelevant background speech and human performance: is there long-term habituation?

In this paper, effects of irrelevant background speech and speech-simulating noise on working memory were investigated. In two experiments which were carried out in Germany and Japan using the same procedure, with totally 12 volunteers serving as subjects, we tested the long-term effects of habituation to the background sound by repeating the experimental sessions three times with intervals of about one week. Using a serial recall task it could be shown that natural background speech impaired significantly the performance. This result is corresponding with former results found by other researchers. Speech-simulating noise, however, did not reveal any effects. The reasons for this lack of effects are discussed. Most important, however, is the finding that there is clearly no effect of habituation to the background speech. While the over-all performance is improved by repeating the experimental sessions, the effects of the experimental background sounds are stable. This result is interpreted in terms of an information-processing approach to the orienting reflex theory. The practical implications of the results are discussed as well.