The effect of speech and speech intelligibility on task performance

Abstract

The aim of this study was to find out what are the effects of three different sound environments on performance of cognitive tasks of varying complexity. These three sound environments were 'speech', 'masked speech' and 'continuous noise'. They corresponded to poor, acceptable and perfect acoustical privacy in an open-plan office, respectively. The speech transmission indices were 0.00, 0.30 and 0.80, respectively. Sounds environments were presented at 48 dBA. The laboratory experiment on 36 subjects lasted for 4 h for each subject. Proofreading performance deteriorated in the 'speech' (p < 0.05) compared to the other two sound environments. Reading comprehension and computer-based tasks (simple and complex reaction time, subtraction, proposition, Stroop and vigilance) remained unaffected. Subjects assessed the 'speech' as the most disturbing, most disadvantageous and least pleasant environment (p < 0.01). 'Continuous noise' annoyed the least. Subjective arousal was highest in 'masked speech' and lowest in 'continuous noise' (p < 0.05). Performance in real open-plan offices could be improved by reducing speech intelligibility, e.g. by attenuating speech level and using an appropriate masking environment.

Unmasking the effects of masking on performance: The potential of multiple-voice masking in the office environment

“…A number of studies have demonstrated that lower STI (or higher privacy) values for task-irrelevant background speech is associated with greater performance (e.g., Ellermeier and Hellbr€ uck, 1998;Haapakangas et al, 2011;Schlittmeier and Hellbr€ uck, 2009). This holds true in visualverbal serial recall (Ellermeier and Hellbr€ uck, 1998;Ebissou et al, 2013;Schlittmeier and Hellbr€ uck, 2009;Haapakangas et al, 2011) as well as in tasks that require processing of meaning and lexical-based retrieval (Haka et al, 2009;Jahncke et al, 2013;Keus van de Poll et al, 2014;Loewen and Suedfeld, 1992;Venetjoki et al, 2006). Yet, as mentioned above, the reason why background speech is less detrimental when its intelligibility is reduced differs, depending on the task at hand.…”

Noise Levels in Two Emergency DepartmentsBefore and After the Introduction of Electronic Whiteboards

“…The effects of noise have also been studied in office settings, with which ED clinicians' coordination centers have some similarities. The findings of these studies include that noise is perceived as more annoying and harmful when it is experienced as uncontrollable, unnecessary or unpredictable [3], that ringing phones and intelligible speech are more distracting than most other noises [27], that intelligible speech at 48 dB(A) deteriorates proofreading more than unintelligible noise at 48 dB(A) [28], that exposure to noise at 50 dB deteriorates the performance of cognitively complex tasks more than a nonoise condition [29], and that an equivalent continuous sound level of 51 compared to 39 dB(A) decreases memory for words [30].…”

Interference of Speech and Interior Noise of Chinese High-Speed Trains with Task Performance

“…Longer distance can reduce auditory distraction by smoothing the perceived variation of sound characters [23,24,25] and by decreasing the signal-to-noise ratio [26,27]. Auditory attention is influenced by other factors such as reverberation [28], the familiarity with the languages of the interfering speech [27,29,30] and combined stimuli. Moreover, substantial intersubject variation exists [31,32,33,34].…”