Effects of irrelevant speech on semantic and phonological judgments of Chinese characters

Abstract

This study employed two decision tasks to investigate whether background speech impairs lexical processing and whether particular characteristics of the background speech differentially contribute to any such impairment. The same set of Chinese character pairs was displayed to two randomly-assigned groups of native-reader Chinese participants with an auditory background of normal Chinese speech, phonotactically-legal meaningless speech, spectrally-rotated speech (i.e., a meaningless sound with no accessible phonological form) or silence. In one task, participants were instructed to decide whether the presented character pair shared the same meaning, and in the other task, whether they shared the same initial phoneme (semantic and phonological judgment task respectively). Participants in the semantic judgment task attained higher accuracy rates and shorter reaction times than those in the phonological judgment task. Phonological properties of meaningless speech produced an increase in participants' reaction times in the phonological judgment task but not the semantic task, whilst the semantic properties of speech produced an increase in participants' reaction times exclusively in the semantic judgment task. The results indicate that background speech is disruptive to lexical processing. Furthermore, primary task demands associated with lexical processing modulate the extent to which participants experience phonological and semantic disruption due to background speech.