Recognition memory in noise for speech of varying intelligibility

This study investigated the extent to which noise impacts speech processing of sentences that vary in intelligibility for normal-hearing young adults. Intelligibility and recognition memory in noise were examined for conversational and clear speech sentences recorded in quiet (QS) and in response to the environmental noise, i.e. noise adapted speech (NAS). Results showed that 1) increased intelligibility through conversational-to-clear speech modifications lead to improved recognition memory and 2) NAS presented a more naturalistic speech adaptation to noise compared to QS, leading to more accurate word recognition and better sentence recall. These results demonstrate that acoustic-phonetic modifications implemented in listener-oriented speech enhance speech processing beyond word recognition. The results are in line with the effortfulness hypothesis (McCoy et al., 2005), which states that speech perception 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 speaking style adaptations on the part of the talker. In addition to enhanced intelligibility, a substantial improvement in recognition memory can be achieved through speaker adaptations to the environment and to the listener when in adverse conditions.