Dissertation Defense: Ben Skerritt-Davis
This presentation will be taking place remotely. Follow this link to enter the Zoom meeting where it will be hosted. Do not enter the meeting before 9:45 AM EDT.
Title: Statistical Inference in Auditory Perception
Abstract: The human auditory system effortlessly parses complex sensory inputs despite the ever-present randomness and uncertainty in real-world scenes. To achieve this, the brain tracks sounds as they evolve in time, collecting contextual information to construct an internal model of the external world for predicting future events. Previous work has shown the brain is sensitive to many predictable (and often complex) patterns in sequential sounds. However, real-world environments exhibit a broader spectrum of predictability, and moreover, the level of predictability is constantly in flux. How does the brain build robust internal representations of such stochastic and dynamic acoustic environments?
This question is addressed through the lens of a computational model based in statistical inference. Embodying theories from Bayesian perception and predictive coding, the model posits the brain collects statistical estimates from sounds and maintains multiple hypotheses for the degree of context to include in predictive processes. As a potential computational solution for perception of complex and dynamic sounds, this model is used to connect sensory inputs with listeners’ responses in a series of human behavioral and electroencephalography (EEG) experiments incorporating uncertainty. Experimental results point toward the underlying sufficient statistics collected by the brain, and the extension of these statistical representations to multiple dimensions is examined along spectral and spatial dimensions. The computational model guides interpretation of behavioral and neural responses, revealing multiplexed responses in the brain corresponding to different levels of predictive processing. In addition, the model is used to explain individual differences across listeners highlighted by uncertainty.
The proposed computational model was developed based on first principles, and its usefulness is not limited to the experiments presented here. The model was used to replicate a range of previous findings in the literature, unifying them under a single framework. Moving forward, this general and flexible model can be used as a broad-ranging tool for studying the statistical inference processes behind auditory perception, overcoming the need to minimize uncertainty in perceptual experiments and pushing what was previously considered feasible for study in the laboratory towards what is typically encountered in the “messy” environments of everyday listening.
Mounya Elhilali, Department of Electrical and Computer Engineering
Jason Fischer, Department of Psychological & Brain Sciences
Hynek Hermansky, Department of Electrical and Computer Engineering
James West, Department of Electrical and Computer Engineering