Shannon Heald (University of Chicago)“Speech Recognition in the Context of Variability: Lessons from Human Listeners”
There is a tremendous amount of variation in the acoustic properties of speech categories. A well-known example of this is the acoustic-phonetic variability found between talkers: different talkers will use the same acoustic pattern to denote different phonetic categories. From this perspective, a change in talker therefore requires a listener to somehow determine the relevant acoustic-phonetic mapping for a newly encountered talker under the current circumstance. Work from my research group has demonstrated that human listeners are able to leverage type (as opposed to token) variability from a difficult-to-understand speaker to rapidly improve their understanding. In the context of adapting to a talker, this work has shown that such generalized learning leads listeners to reorganize the way they selectively process and rely on acoustic features for the given talker. This empirical finding supports the hypothesis that human listeners capitalize on recent systematic variance in the speech signal to determine the most diagnostic acoustic-phonetic cues for a talker under the given circumstance. As such, I will argue that the ability to leverage lawful variability in the speech signal can be thought of as a very general system human listeners use to deal with the problem of pattern variability, allowing them to maintain robust phonetic constancy even when faced with systematic noise or acoustic distortions.
Dr. Shannon Heald is a cognitive neuro-psychologist from the University of Chicago. As a professional researcher, her work focuses on understanding how our experiences shape and guide (1) how we perceive the world, (2) how we communicate with one another, and (3) how we think and behave. Her work utilizes methods from multiple disciplines including behavioral research methods, analytic methods of linguistics, and electrophysiology (specifically, electroencephalography or EEG). Dr. Heald’s research has been published in a number of high-impact peer reviewed journal articles including Cognitive Psychology, Brain & Language, Current Opinion in Behavioral Sciences, Psychology of Learning and Motivation, Psychological Science, Psychonomic Bulletin & Review, and The Quarterly Journal of Experimental Psychology. She earned her undergraduate degree in Psychology in 2002, a master’s degree in Social Sciences in 2005, and a PhD in Cognitive Psychology in 2012, all from the University of Chicago. After her PhD, she completed a 6-year postdoctoral appointment at the University of Chicago, gaining further specialization in systems-level neuroscience methodology.