Many factors weigh into how we perceive the world, and last night we tapped into two areas: hearing and memory, at a “Pint of Science” gathering at DROM in the East Village. Beer in hand, attendees packed the venue, eager to learn more from hometown scientists James Hudspeth of Rockefeller University and Paula Croxson of Mount Sinai.
Hudspeth, a Dana Alliance member and hearing expert, spoke about how hearing works, and the role of tiny hair cells in the cochlea. As explained on his Howard Hughes Medical Institute page, “Each cochlea normally contains about 16,000 hair cells, which convert mechanical inputs derived from sounds into electrical signals that the brain can interpret.”
It is the loss of these hair cells, which don’t regenerate in humans, that leads to the most common form of hearing loss, said Hudspeth. Lucky for us, other species can regenerate these cells (amphibians and reptiles, for example). Dr. Hudspeth is using zebra fish in his lab to study this ability; he hopes new therapies can be produced for people in the next five to ten years. In the meantime, cochlear implants are being used by more than 300,000 people in the US.
In what I found to be the most fascinating part of his talk, Hudspeth played three videos of what hearing sounds like with implants with differing numbers of electrodes. The three variations were five, ten, and 20 electrodes (considered the current state of the art). I was surprised that none of them sounded particularly clear. The implants with five and ten electrodes simply sounded like noise, though one member in the audience was able to make out a few words. For the 20 electrode implant, the words were muffled but relatively discernable. I couldn’t find the exact videos played by Hudspeth, but a video by Arizona State University in a 2014 article from the UK’s The Telegraph gives you an idea of what hearing through a cochlear implant can sound like.
After a brief break, the night’s second speaker, Paula Croxson, took the stage for her talk, “Your Lying Brain.” Focusing on how perception and memory influence each other, Croxson gave multiple examples of how our brains can lead us astray.
In what is known as the McGurck effect illusion, a video of a man repeating “ba ba ba,” is replaced with the same man mouthing “fa fa fa,” while the sound of “ba ba ba,” continues to play. Watching the second video, it sounds as though the man truly is saying “fa fa fa.” The video illustrates how what we see can influence what we hear.
While this illusion is a fun example of tricking our brain, what about instances where our “lying brains” have societal repercussions? Croxson cited the work of Elizabeth Loftus, an expert on memory distortion and false memories, who has highlighted the shortcomings of eyewitness testimony.
In a study published in 1974, people were shown videos of car accidents and then asked how fast cars were going when the incidents occurred. Lotfus asked some people the speed when the cars “hit,” and other people the speed when the cars “smashed.” The latter group estimated an average car speed of 7 mph faster. “Smashed” sounds faster than “hit,” explained Croxson, who cautioned against using leading words in questioning. This type of research obviously has implications for legal protocol, and is something that is frequently discussed in the media.
Pint of Science holds a monthly gathering at Ryan’s Daughter on the Upper East Side in New York City. It also hosts events in 14 other US cities and ten countries. Sunday’s event was held in collaboration with braiNY, a series of fun and fascinating events about the brain in New York City as part of Brain Awareness Week (March 14-20).
– Ann L. Whitman