Irrelevant background speech causes dissatisfaction and impairs cognitive performance in open‐plan offices. The model of Hongisto (2005, Indoor Air, 15, 458‐468) predicts the relation between cognitive performance and the intelligibility of speech described with an objectively measured quantity, the Speech Transmission Index (STI). The model has impacted research in psychology and room acoustics as well as the acoustic design guidelines of offices. However, the model was based on scarce empirical data. The aim of this study was to revise the model based on a systematic literature review, focusing on laboratory experiments manipulating the STI of speech by wide‐band steady‐state noise. Fourteen studies reporting altogether 34 tests of the STI‐performance relation were included. According to Model 1 that includes all tests, performance begins to decrease approximately above STI = 0.21 while the maximum decrease is reached at STI = 0.44. Verbal short‐term memory tasks were most strongly and very consistently affected by the STI of speech. The model for these tasks showed a deterioration in performance between STI 0.12 and 0.51. Some evidence of an STI‐performance relation was found in verbal working memory tasks and limited evidence in complex verbal tasks. Further research is warranted, particularly concerning task‐specific effects.

中文翻译：

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不相关语音的清晰度与认知表现之间的关系-基于实验室研究的修正模型。

不相关的背景语音会导致开放式办公室中的不满和认知能力下降。Hongisto（2005，室内空气，15，458-468）模型预测了认知表现与语音清晰度之间的关系，并用客观测量的量语音传输指数（STI）进行描述。该模型影响了心理学和室内声学的研究以及办公室的声学设计准则。但是，该模型基于稀缺的经验数据。这项研究的目的是在系统的文献综述的基础上修订该模型，重点是通过宽带稳态噪声操纵语音STI的实验室实验。十四项研究总共报告了STI的34项测试-绩效关系包括在内。根据包含所有测试的模型1，性能开始大约在STI  = 0.21以上下降，而在STI  = 0.44时达到最大下降。口头短期记忆任务是最强烈的，非常一致受到STI讲话。这些任务的模型显示出性能在STI 0.12和0.51之间下降。一个的一些证据STI -性能关系的工作记忆任务中发现和限制在复杂的口头任务的证据。有必要进行进一步的研究，尤其是针对特定任务的效果。