Recognition memory in noise for speech of varying intelligibility

Abstract

Speech intelligibility is greatly affected by the presence of noise. However, there has been little research investigating the effects of noise on recognition memory. Per the effortfulness hypothesis (McCoy et al., 2005), we expect that processing speech in challenging listening environments requires additional processing resources that might otherwise be available for encoding speech in memory. This resource reallocation may be offset by speaker adaptations to the environment and to the listener. Here we compare recognition memory for conversational and clear speech sentences recorded in quiet (QS) and for sentences produced in response to the actual environment noise, i.e. noise adapted speech (NAS). Listeners heard 40 unique conversational and clear QS or NAS sentences mixed with 6-talker babble at SNRs of 0 or +3 dB. Following the exposure, listeners identified 80 sentences in quiet as old or new. Results showed that 1) increased intelligibility through conversational-to-clear speech modifications leads to improved recognition memory and 2) NAS presents a more naturalistic speech adaptation than QS, leading to better sentence recall for listeners. This experiment suggests that acoustic-phonetic modifications implemented in listener-oriented speech lead to improved speech recognition in challenging listening conditions and, crucially, to a substantial enhancement in recognition memory for sentences.