Introduction to Psychology · Sensation and Perception

Hearing and Audition

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In 30 seconds
Why this matters
The college version
Eli explains
Worked example
Key takeaway
Study tools

In 30 seconds

(hearing) converts the physical energy of into neural signals the brain interprets as sound. Sound waves are described by their (which we perceive as ) and (which we perceive as ). Vibrations travel through the outer ear to the , through the middle ear , and into the , where on the transduce the vibrations into signals carried by the . Pitch is explained partly by where the basilar membrane vibrates (place theory) and partly by the timing of neural firing (temporal theory), while binaural cues let us localize where sounds come from.

Why this matters

Recognizing hearing loss early matters in healthcare and education: untreated childhood hearing loss is associated with delayed language and academic development, so newborn hearing screening and classroom accommodations (seating near the teacher, visual aids, assistive devices) are standard, person-first practices. In occupational health, noise exposure is a regulated hazard managed with hearing protection and sound-level monitoring. Because hearing loss varies in cause and degree, respectful language ("a person who is deaf or hard of hearing") and individualized support are emphasized.

The college version

1. Sound Waves and Their Perceptual Qualities

Sound waves are pressure waves in a medium (usually air) created by a vibrating source. They have two key physical properties. Frequency is the number of wave cycles per second, measured in hertz (Hz); it corresponds to the perceptual quality of pitch — high frequency means high pitch. Amplitude is the height or intensity of the wave, related to how much pressure it exerts; it corresponds to loudness, typically measured in decibels (dB). Frequency and amplitude are physically independent, so a sound can be high-pitched but quiet, or low-pitched but loud.

2. The Ear: Outer, Middle, and Inner

The outer ear includes the pinna (the visible ear) and the auditory canal, which funnel sound waves to the tympanic membrane (eardrum), a thin membrane that vibrates with the incoming wave. The middle ear is an air-filled cavity containing three tiny bones — the ossicles (malleus/hammer, incus/anvil, stapes/stirrup) — which amplify the eardrum's vibrations and pass them to the oval window of the inner ear. The inner ear contains the cochlea, a fluid-filled, snail-shaped structure. Inside the cochlea, the basilar membrane runs along its length; riding on it are receptor cells called hair cells. When fluid waves bend the basilar membrane, the hair cells' tiny cilia brush against an overlying membrane, opening ion channels and triggering neural signals. Those signals travel along the auditory nerve to the brainstem and up to the auditory cortex in the temporal lobe.

3. Theories of Pitch and Sound Localization

Two complementary theories explain how we hear pitch. Place theory holds that different frequencies cause the basilar membrane to vibrate maximally at different places (high frequencies near the base, low frequencies near the apex), and the brain reads pitch from where the membrane is most active — best for high-frequency sounds. Temporal theory (also called frequency theory) holds that the rate of neural firing matches the frequency of the sound — best for low-frequency sounds. Together, the "volley" principle covers the middle range. Sound localization is our ability to tell where a sound comes from, relying largely on binaural cues — differences between what the two ears receive: an interaural time difference (sound arrives slightly earlier at the near ear) and an interaural intensity difference (the head casts a "sound shadow," making the sound louder at the near ear).

How it works

Sound waves enter the outer ear and strike the tympanic membrane, making it vibrate.
The ossicles amplify these vibrations and push against the oval window.
Pressure waves move through the cochlear fluid, bending the basilar membrane.
Hair cells on the membrane bend, opening ion channels and generating neural signals.
The auditory nerve carries these signals through the brainstem to the auditory cortex.
The brain combines frequency, timing, and binaural information into the experience of pitch, loudness, and location.

Common confusions

Do not confuse	With	Difference
Frequency	Amplitude	Frequency is the rate of waves (pitch); amplitude is the size/intensity of waves (loudness).
Pitch	Loudness	Pitch is high/low; loudness is soft/loud.
Tympanic membrane	Cochlea	Eardrum transmits vibration; the cochlea transduces it into neural signals.
Place theory	Temporal theory	Place theory uses location on the basilar membrane; temporal theory uses timing of firing.
Conductive hearing loss	Sensorineural hearing loss	Conductive = outer/middle ear blockage; sensorineural = hair-cell/nerve damage.
Binaural cues	Monocular cues (vision)	Binaural cues use two ears; monocular cues use one eye (depth).

Memory aids

Use the word "FAP LOTS" to pair the physical and perceptual halves: Frequency→Pitch, Amplitude→Loudness; then Outer→Middle→Inner ear (OMI, "oh my!"), and Temporal vs. Place for Timing vs. Place. ("FAP LOTS" = Frequency-Amplitude-Pitch-Loudness, OMI, Timing-vs-Place.)

Quick review

Topic Recap

Audition turns the physical properties of sound waves — frequency (pitch) and amplitude (loudness) — into perception. Sound travels outer ear → tympanic membrane → ossicles → cochlea, where hair cells on the basilar membrane transduce vibrations into auditory-nerve signals. Place theory and temporal theory together explain pitch, and binaural cues explain localization. Hearing loss is classified as conductive or sensorineural, with noise exposure a leading preventable cause.

Knowledge Check

A high-frequency sound wave is most likely to be perceived as which quality?
Which structure directly vibrates in response to incoming sound waves at the boundary of the outer and middle ear?
According to place theory, high-frequency sounds produce maximum vibration near which end of the basilar membrane?
What two types of binaural cues help us localize sound?
Damage to the hair cells of the cochlea produces which type of hearing loss?

Answers and Rationales

High pitch. Frequency is the physical property that maps onto pitch.
The tympanic membrane (eardrum). It is the first structure to vibrate, sitting between the outer and middle ear.
The base (near the oval window). Place theory holds high frequencies peak near the base and low frequencies near the apex.
Interaural time difference and interaural intensity difference. These are the two classic binaural cues.
Sensorineural hearing loss. Hair-cell or auditory-nerve damage is sensorineural, the most common type from aging and noise.

Eli explains

The same idea, in plain words

Explain it like I’m 10

Imagine a speaker cone pushing and pulling on the air around it. Each push squeezes air molecules together, and each pull spreads them apart, creating a traveling wave of pressure — that is a sound wave. Your ear is a machine that catches those pressure waves and turns them into electricity your brain can read, much like a microphone turns sound into an electrical signal.

Here is a comparison: vision reports what something looks like, but hearing detects mechanical vibrations in air, water, or solid objects — telling you that something is happening, even behind you or in the dark, because sound reaches you from every direction.

Where this stops being exact: the ear is not a simple microphone — it actively filters and amplifies, and "hearing" is actually built in the brain, which reconstructs pitch, loudness, and location from patterns of nerve firing.

Simple Example

When someone plucks a guitar string, the string vibrates back and forth, pushing the air and creating a sound wave. A thin, tightly stretched string vibrates quickly (high frequency), and you hear a high pitch. If you pluck harder, the string swings farther (higher amplitude), and you hear a louder note — even though the pitch stays the same.

Worked example

From anatomy to theory. Georg von Békésy's classic studies of the basilar membrane (observing traveling waves in the cochlea of cadavers and models) provided direct evidence for place theory: high-frequency tones produced peak displacement near the cochlear base, low frequencies near the apex. His work earned a Nobel Prize and shaped modern cochlear-implant design.
Correlation, not causation. Studies find chronic noise exposure (loud workplaces, concerts, headphones at high volume) is correlated with hearing loss, but many are observational, so researchers must rule out confounding variables (age, genetics, other conditions) before claiming noise alone causes loss. Randomized experiments exposing people to damaging noise would be unethical — a key methodological limit.
Types of hearing loss. Conductive hearing loss involves a problem in the outer or middle ear (e.g., a damaged eardrum, fluid, or ossicle) that blocks transmission; sensorineural hearing loss involves damage to the cochlea's hair cells or the auditory nerve — the most common type from aging and noise exposure, and generally permanent. Mixed loss combines both.
Application. Because hair cells in mammals do not regenerate, prevention (hearing protection, limiting volume and duration) is the primary evidence-based strategy. Cochlear implants bypass damaged hair cells by electrically stimulating the auditory nerve directly, a technology that rests squarely on place theory.

Key takeaways

High yield: Frequency → pitch; amplitude → loudness.
High yield: The ossicles amplify sound; the cochlea transduces it.
High yield: Hair cells are the sensory receptors for hearing; their loss is the main cause of sensorineural hearing loss.
High yield: Place theory (where) vs. temporal theory (timing) explain different pitch ranges.
High yield: Binaural cues (time + intensity differences) enable sound localization.
Conductive loss is in the outer/middle ear; sensorineural loss is in the cochlea/nerve.
Hair cells do not regenerate in humans, so prevention of noise-induced damage is critical.

Keep learning

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Study tools & related lessonsYou’ll learn to · Key vocabulary · Related

You’ll learn to

Describe the physical properties of sound waves (frequency and amplitude) and the perceptual qualities they produce (pitch and loudness).
Trace the path of sound through the outer, middle, and inner ear, naming each structure and its function.
Compare place theory and temporal theory of pitch perception and explain how binaural cues support sound localization.
Distinguish the types and causes of hearing loss, including the role of noise exposure, in non-stigmatizing terms.

Key vocabulary

Audition: The sense of hearing.
Sound waves: Pressure waves in a medium produced by a vibrating source.
Frequency: Number of wave cycles per second (Hz).
Pitch: The highness or lowness of a sound.
Amplitude: The height/intensity of a sound wave.
Loudness: The perceptual experience of sound intensity (dB).
Outer/middle/inner ear: Three anatomical divisions that funnel, amplify, and transduce sound.
Tympanic membrane: The eardrum; vibrates with incoming sound waves.
Ossicles: The three middle-ear bones (malleus, incus, stapes).
Cochlea: Fluid-filled, coiled inner-ear structure.
Basilar membrane: Membrane running through the cochlea.
Hair cells: Sensory receptor cells on the basilar membrane.
Auditory nerve: Nerve carrying signals from the cochlea to the brain.
Place theory: Pitch is coded by where the basilar membrane vibrates.
Temporal theory: Pitch is coded by the rate/timing of neural firing.
Sound localization: Determining where a sound originates.
Binaural cues: Time and intensity differences between the two ears.
Hearing loss: Reduced sensitivity to sound (conductive or sensorineural).
Noise exposure: Sustained or intense sound that can damage hair cells.

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