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

This study investigated whether background speech impairs lexical processing and how speech characteristics modulate such influence based on task type. Chinese character pairs were displayed to native Chinese readers under four auditory conditions: normal Chinese speech, phonotactically legal but meaningless speech, spectrally-rotated speech (i.e. meaningless sound with no accessible phonological form), or silence. Participants were tasked with determining whether the presented character pair shared the same meaning (semantic judgment), or the same initial phoneme (phonological judgment). Participants performed better and faster in the semantic than in the phonological judgment task. Phonological properties of meaningless speech prolonged participants’ reaction times in the phonological but not the semantic judgment task, whilst the semantic properties of speech only delayed reaction times in the semantic judgment task. The results indicate that background speech disrupts lexical processing, with the nature of the primary task affecting the extent of phonological and semantic disruption.