Research ~ Lori L. Holt ~ Carnegie Mellon University

Despite the fact that speech communication is a fundamental part of our daily behavior, its mechanisms are not yet well understood. In our research, we use a three-tiered approach to studying speech perception. Much work focuses on empirical data collected in perceptual and learning paradigms with human participants. In addition, we also examine the behavior of nonhuman animals. This work makes it possible to address questions that are unanswerable with human participants. Finally, the human and nonhuman empirical data are complemented by computational approaches aimed at modeling these behaviors.

Conceptually, this research can be divided into two broad categories. One line of work is aimed at examining mechanisms by which experience shapes perceptual organization of speech. Well before infants reach their first birthday, they have begun to perceive speech sounds in a manner that has been shaped by their native language community. Ongoing research is aimed at discovering the learning mechanisms by which this developmental milestone occurs and the influence this has on speech perception later in life, such as in learning a second language.

The other primary area of research addresses the perceptual mechanisms by which complex auditory signals (like speech) are processed. Through the use of human and animal perceptual data and computational models, this research endeavors to explain the general perceptual factors that influence speech communication. Recent studies have investigated how context affects speech perception.

The questions that arise from these two areas touch upon some long-debated issues in cognitive science. For example, is language acquisition guided by specialized processes or is it instead directed by more general mechanisms? Is speech perceived in a manner that is similar to the way that we perceive other sounds? Or does it require specialized language mechanisms? What are the representations critical for spoken language processing? The goal of this research is to develop the answers to these central questions.