Speech-to-Song Illusion (Emilia Previty)
Title:
Principle(s) Investigated:
Mechanical waves
Principles of Hearing
Auditory processing
Standards:
MS-LS1-3. In multicellular organisms, the body is a system of multiple interacting subsystems. These subsystems are groups of cells that work together to form tissues and organs that are specialized for particular body functions; Systems may interact with other systems; they may have sub-systems and be a part of larger complex systems.
MS-LS1-8. Each sense receptor responds to different inputs (electromagnetic, mechanical, chemical) transmitting them as signals that travel along nerve cells to the brain. The signals are then processed in the brain, resulting in immediate behaviors or memories.
Materials:
Speakers or headphones
Deutsch audio clips
Procedure:
Have students listen to the sound clip. Describe it on a scale from speech to musical. Listen to the same clip repeated 10 times. Describe it on a scale from speech to musical. Have them discuss why they may change their answers between clips of the same audio.
Student Prior knowledge:
Students need to know the concept of sound and hearing.
Explanation:
"Music starts as sound, but something happens in the brain and it transforms." Speech-to-sound illusion is considered a phenomenon of both language and music. There are two processes that happen when we hear sounds: the physical process that creates sound energy and the psychological process that happens inside our ears and brains. Sound is produced by vibrations; this creates sound waves which can be transferred through the air. These sound waves enter through our ears and travel down our ear canal, to our inner ear and cochlea. The cochlea has fluid inside it which ripples and moves hair cells, which allow ions to pass through the cochlear nerve and straight to the brain (Schley, 2019). This auditory information is then processed in the brain, specifically the auditory cortex. Our brains then use this information and can process it as speech, sound, or music. This process combines multiple systems in your body, including your ears (outer ear, middle ear, inner ear) and the central nervous system, It demonstrates how nerve signals are created in your inner ear then transmitted to your brain to process as speech or music.
Questions & Answers:
1. How are sound waves produced?
Sound is the mechanical waves produced by repeating vibrations of particles in the air. Sound can travel through air and water. For example, a tine can vibrate repeatedly; they compress and displace the air particles around them. This turns into a repeating pattern of compressions which translate to a single tone.
2. How does the auditory cortex process sounds?
Once sound waves are translated into electrical signals, they are sent to the auditory cortex of the brain. There, neurons receive these signals and translate them "into a language that our brain understands" ("How the brain processes sound signals", 2013). Sound can be consciously and unconsciously perceived. Sudden sounds can cause us to react quickly and involuntarily. Sounds, like communication or music, can be related to our memories.
3. How does the brain tell music apart from speech/environmental sound?
There isn't a specific answer for this question yet, since not much research has been done on this phenomenon; the research is still in its infancy. What we can guess is that "our love for rhythm, repetition, and harmony evolved gradually through the other primates" (Posner, 2018). A key player is repetition, since one only needs to add repetition to make something sound musical. Evolution may be telling us to create or enjoy music, we just don't fully know why.
Applications to Everyday Life:
Sound processing is used all the time, every day. Music can be applied to therapy, for example, to treat movement disorders like Parkinson's or even Alzheimer's. The brain's motor system can actually register a beat, which explains why it's so helpful for movement disorders. Music can be used to retrain the brain to learn how to speak. When damage is done to the motor cortex, the other side of the brain that processes music can be used to then process speech. Music also can be used to improve the human experience. It creates a cultural community, since every single culture on Earth uses music in some form or another. If a child learns to make music early in life, it can give them advantages to learning language. Music also can be an effective teaching tool, since it makes remembering information easier.
Photographs:
Videos:
Sources:
Deutsch, D. (n.d.). Speech to Song Illusion. Retrieved from http://deutsch.ucsd.edu/psychology/pages.php?i=212.
How the brain processes auditory signals. (2013, May 2). Retrieved from https://www.hear-it.org/How-the-brain-processes-auditory-signals.
Netflix. (2018, September 19). Music. Explained. Retrieved from https://www.netflix.com/watch/80243768?trackId=200257859
Schley, L. (2019, March 6). Inner Ear Discovery Helps Explain How Sound Waves Become Brain Signals - D-brief. Retrieved October 14, 2019, from http://blogs.discovermagazine.com/d-brief/2019/03/06/discovery-explains-how-we-hear/#.XaVUiudKjOQ.
Science Buddies. (2016, March 24). Making Sound Waves. Retrieved from https://www.scientificamerican.com/article/making-sound-waves/.
Science World. (2019, July 17). Speech-to-Song Illusion. Retrieved October 14, 2019, from https://scienceworld.ca/resources/activities/speech-song-illusion.
Victoria State Government: Education and Training. (2018, September 5). Investigating Sound and Hearing. Retrieved from https://www.education.vic.gov.au/school/teachers/teachingresources/discipline/science/continuum/Pages/soundlearn.aspx#1.