The Frequency Theory of Hearing and Pitch Perception

Subject : Biology

Question:

The proposition that pitch is decoded from the rate at which hair cells of the basilar membrane are firing is known as the:

A. Resonance theory of hearing

B. Frequency theory of hearing

C. Volley theory of hearing

D. Place theory of hearing

Expert Verified Answer:

The correct answer is B. Frequency theory of hearing.

The frequency theory of hearing explains how we perceive the pitch of a sound based on the rate at which hair cells in the basilar membrane of the inner ear fire electrical signals. This theory is most effective in describing how we detect low-frequency sounds. According to the frequency theory, the pitch of a sound is directly related to how often the auditory nerve fibers connected to the hair cells fire.

For example, if a sound wave with a low frequency enters the ear, the hair cells will fire at a slower rate, corresponding to the frequency of the wave. In contrast, for higher-frequency sound waves, the hair cells will fire more rapidly. This continuous firing rate allows the brain to decode and perceive the pitch of the sound based on how fast the nerve cells are sending signals.

However, this theory mainly applies to low-pitched sounds. For higher frequencies, the place theory of hearing (D) is more applicable. Place theory suggests that different frequencies activate different locations along the basilar membrane, and this spatial activation helps the brain interpret higher pitches.

While the resonance theory of hearing (A) was an early theory, it has been largely replaced by more accurate models such as the frequency and place theories. The volley theory of hearing (C) is another explanation that works for mid-range frequencies, suggesting that groups of neurons work together to fire in rapid succession, covering frequencies higher than individual neurons can manage alone.

Frequency theory plays a key role in our understanding of how the human ear decodes low-frequency sounds by examining the rate of firing of hair cells on the basilar membrane.