When speech is heard in the presence of background sound, or when hearing is impaired, the sensory information at the ear is often too ambiguous to support speech recognition by itself. And yet speech is often perceived successfully in such conditions – how is this possible? I will review two active areas of research that are relevant to this question. First, I will review recent literature related to the importance of prior knowledge and experience in predicting and constraining interpretation of incoming sound. Different types of knowledge (such as the meaningful context within which an utterance is heard, or familiarity with someone’s voice, or familiarity with the reverberation characteristics of a particular space) all appear to facilitate speech perception, but may do so in different ways. In the first part of the presentation, I will present recent work that illustrates the importance of different sources of knowledge, and how these may act to facilitate speech understanding. In the second part of the presentation, I will survey evidence suggesting that cognitive factors such as working memory and selective attention have an important role to play in facilitating speech perception in noisy environments. Finally, I will conclude by describing how listening effort – a concept that has recently become more popular in audiology since it may relate to important individual differences in outcome after intervention that are otherwise unexplained by speech-perception measures – can be understood in relation to the cognitive factors described.
1. Describe different ways in which knowledge and experience can facilitate perception of noisy and ambiguous speech.
2. List the cognitive factors that influence perception of noisy and ambiguous speech.
3. Recognize that listening effort can be understood as the interaction between listening conditions and cognitive factors.