Department of
Psychological and Brain Sciences

• Cognitive Science

• Psycholinguistics, speech perception, production and synthesis, perceptual development
• Spoken language comprehension, voice I/O technology, human factors
• Hearing impairment, cochlear implants, individual differences, and multi-modal perception of speech

We are interested in gaining a better understanding of the earliest stages of speech perception and specifying how the initial acoustic-phonetic information in the speech signal interacts with other sources of knowledge to support spoken word recognition, lexical access and spoken language processing. The proposed research is divided into the following four major projects:

Project 1: Spoken Word Recognition and the Mental Lexicon
This project investigates the role of the lexicon in speech perception and spoken word recognition using both computational and behavioral techniques. The major goal is to understand the structural organization of words in the mental lexicon and its contribution to spoken word recognition.

Project 2: Contextual Variability in Spoken Word Recognition 
This project is concerned with the perception of spoken words and sentences in isolation and in a variety of linguistic and pragmatic environments. The major goal is to learn more about speech variability and the effects that different sources of variability have on speech perception and spoken word recognition. We are interested in how listeners encode variability in long-term memory, the role of specific instances in perception and how this information affects speech perception and spoken word recognition.

Project 3: Perceptual Learning 
This project is concerned with perceptual learning and adaptation in speech perception and spoken word recognition. We are interested in how listeners learn to adapt to novel voices, unfamiliar dialects and different speaking rates. We also want to gain a better understanding of how "indexical" information in the speech signal is used to facilitate acoustic-phonetic analysis and how it contributes to spoken word recognition and the retention of information in long-term memory.

Project 4: Individual Differences and Working Memory 
This project investigates the underlying basis for the large individual differences in speech perception, word recognition and language abilities observed among prelingually deaf children with cochlear implants. The major goal of this project is to identify the source of individual differences in word recognition performance in these children in terms of the speed and efficiency of phonological coding and rehearsal processes which are used in a wide range of language processing tasks. We are also interested in testing the hypothesis that differences in working memory span in these children reflect a loss of perceptual distinctiveness in their phonological representations.