Many hearing loss patients have the same complaint: They have trouble following conversations in a noisy space. Carnegie Mellon University’s Barbara Shinn-Cunningham has spent her career conducting research to better understand this problem and how it affects people at cocktail parties, coffee shops and grocery stores.
Now, along with a team of researchers from six universities, Shinn-Cunningham, the director of CMU’s Neuroscience Institute (NI) and the George A. and Helen Dunham Cowan Professor of Auditory Neuroscience, is looking for answers in an unexpected place. The researchers will conduct noninvasive experiments on free-swimming dolphins and sea lions.
Dolphins and sea lions hear differently than humans, but the way their brains make sense of sound could help Shinn-Cunningham and her team better understand the cognitive and neural mechanisms of sound processing. The researchers have received a Multidisciplinary University Research Initiative grant from the Department of Defense to investigate how animals understand and respond appropriately to the cacophony reaching their ears.
The team will conduct several different experiments.
Working with a world expert on dolphin behavior, they will train dolphins to identify targets, shapes such as a spheroid or a cross, and then ask the dolphin to identify the target from among similar, distracting shapes using their special auditory sense: echolocation. By engineering the distractor shapes to be more or less like the target, the experimenters will determine what sound features the dolphins use to "see" with sound.
In a different series of studies, the team will explore whether dolphins, like humans, learn to anticipate repeating patterns in sound, a critical step in making sense of complicated sounds in noisy settings. In this work, they will use electroencephalography (a technology used routinely with humans in laboratories and clinics) to measure neural responses from the dolphins to see if the brain shows a surprise signature when the ongoing sound pattern changes.