Incidental Auditory Category Learning
We are investigating how listeners learn to categorize complex distributions of sounds incidentally, as they navigate a (videogame) environment. This learning takes place without overt category decisions, directed attention to the sounds, or explicit feedback about categorization. Our studies demonstrate the importance of this learning in speech and nonspeech auditory learning, and in understanding developmental dyslexia.
The Role of Auditory Learning in Developmental Dyslexia
Even in a country like the United States, the economic and societal costs of low literacy are enormous. Yet, we do not yet adequately understand learning mechanisms that support literacy, or how they may fail in low literacy. In an NSF-supported project in collaboration with Drs. Yafit Gabay and Avi Karni of the University of Haifa, we are examining procedural auditory category learning across distinct samples varying in literacy attainment, age, and native language. Our goal is to advance understanding of the basic building blocks of literacy.
Relevant publications: Gabay & Holt, 2015; Gabay, Thiessen, & Holt, 2015; Gabay et al. 2015.
Webinar: Dispelling the Myths of Dyslexia, CMUThink, Dr. Lori Holt, February 2018
Training Sustained Auditory Selective Attention
We have developed a new online training task, the 'Silent Service,' to examine how auditory attention improves with training. This deep-water-exploration-themed videogame was designed in partnership with Rajeev Mukundan and Na-Yeon Lim of CMU's Entertainment Technology Center and Dr. Fred Dick, with support from the National Science Foundation. This branch of our reserach has implications for improving the daily lives of those with traumatic brain injury, ADHD, and autism.
The Neurobiology of Auditory Attention
Listening to a friend while walking down a busy street, tracking the quality of a sick child’s breathing through a nursery monitor, and following the melody of a violin within an orchestra all require singling out a sound stream (selective attention) and maintaining focus on this stream over time (sustained attention) so that the information it conveys can be remembered and responded to appropriately. In collaboration with Dr. Fred Dick of Birkbeck College, London, we have been investigating the neurobiological basis of sustained auditory selective attention in human auditory cortex.
Relevant publication: Dick, Lehet, Callaghan, Keller, Sereno, & Holt, 2017
Stability and Plasticity in Speech Perception
The complex mapping of speech to language-specific units like phonemes and words must be learned over time. Even in adulthood, the learning rapidly online as we hear speech. The mapping from speech acoustics to phonemes and words is 'tuned' by experience that departs from the norm, as in listening to a foreign accent. We have been investigating how the perceptual system maintains stable long-term representations of language-specific units even as it flexibly adapts to short-term speech input.