Podcast Summary: Unexplainable — The Sound Barrier #3: What Does Silence Sound Like?

Date: November 10, 2025
Host: Noam Hassenfeld (Vox)
Guests:

• Erin Westgate (Psychologist, University of Florida)
• Raja Goh (PhD student, Johns Hopkins)
• Melody Baglione (Professor of Mechanical Engineering, Cooper Union)
• William Marx (John Cage’s 4'33'' performer, via archival audio)

Overview

This episode investigates the mystery of silence—how something that, on the surface, is “nothing” can have powerful, complicated effects on our minds and perceptions. Through psychological experiments, philosophical debate, audio illusions, and a journey into an anechoic chamber (one of the quietest rooms on earth), host Noam Hassenfeld and guests illuminate how silence is processed by the mind, how it can be deeply unsettling or intensely meaningful, and whether we ever truly experience “pure” silence.

Key Discussion Points & Insights

1. Why Is Silence So Uncomfortable?

[01:25–03:41]

• Erin Westgate’s Research:
  • Intention: Initially aimed to create well-being by giving people quiet time for reflection.
  • Outcome: Most people disliked sitting alone in silence. “They said things like brushing their teeth was better.” — Erin Westgate [02:00]
  • Follow-up: Given options between silence and unpleasant stimuli (vomiting, nails on a chalkboard, etc.), people overwhelmingly preferred the unpleasant sounds.
  • Escalation: In another study, participants could shock themselves instead of sitting in silence. Nearly half did.
  • “People actually do something that's painful rather than simply sit in silence.” — Erin Westgate [03:34]

2. The Paradoxes and Powers of Silence

[03:41–05:06]

• Despite its discomfort, silence and sensory deprivation have been shown to reduce anxiety and even foster brain growth—in mice, exposure to silence increased new neurons.

• Noam introduces the main enigma: “How can something that's nothing do so much?” [03:41]

3. Is Silence Just an Absence, or a Real Experience?

[05:06–06:06]

• Raja Goh’s Symphonic Experience:
  • Being hit by palpable silence after a symphony’s crescendo led him to question whether silence is simply ‘nothing,’ or something we actively, consciously experience.
  • Philosophical debate: Is silence an experience unto itself, or just the lack of sound?
  • “There is a genuine experience of silence … there's something it's like to experience silence.” — Raja Goh [05:53]

4. The ‘One Is More’ Illusion, Sound vs. Silence

[06:19–11:21]

• Auditory Illusions:

  • “One Is More” Illusion: When playing two short boops vs. one long boop of equal duration, listeners perceive the single boop as longer.
  • “That's why it's called the One is More Illusion. One sound seems longer than two.” — Noam Hassenfeld [06:45]

• Applying the Illusion to Silence:

  • Raja ran experiments where restaurant background noise was punctuated by either two short silences or one long silence (of equal length).
  • Result: The single silence was perceived as longer, paralleling the original auditory illusion.
  • "It definitely does seem like exactly the same mechanism is at play." — Raja Goh [10:43]
  • Suggests our brains process silences as real, positive inputs, not merely absences.

5. Entering the Quietest Room — The Anechoic Chamber

[13:59–16:59]

• Visit with Melody Baglione, Cooper Union:

  • Description: The anechoic chamber is engineered to eliminate echo, covered with fiberglass wedges, with a suspended catwalk to avoid contact with sound-absorbing floors.
  • Urban legends: Time in anechoic chambers reportedly causes nausea or hallucinations, but no clear evidence.
  • Personal experience: Noam describes the silence as “thick, like I’m wading into jello,” with the absorption of all echoes leading to a surreal lack of auditory feedback.
  • “I'm screaming in a room, and it's really quiet. That's really weird. That's so weird.” — Noam Hassenfeld [16:59]

• Physiological Effects:

  • Adaptive response: Just as eyes adjust in darkness, ears begin to pick up internal sounds—breathing, heartbeat, high-pitched tinnitus.
  • Noam confesses: “I feel like I can hear noises from my own head and I can’t tell if I’m making them up or not. ... like reverse seashell.” [17:32]

6. John Cage, 4’33’’, and the Artistry of Silence

[18:42–22:52]

• Composer John Cage’s Revelation:

  • In an anechoic chamber, Cage realized he could not eliminate all sound—what remained were internal bodily noises.
  • “There’s no way to stop the reception of sound. If you stop the sounds from the outside, then what you hear are the sounds that are coming from the inside.” — John Cage [19:01]

• Cage’s 4’33’’:

  • Performance consists of a pianist not playing for 4’33”; the “music” becomes all ambient noise.
  • Audience experiences: Hearing the breeze, raindrops, and eventually the murmurs of people talking becomes the performance.
  • “There is no such thing as silence.” — William Marx [22:52]

• Personal anecdote: Noam’s own 4’33’’ experience reoriented how he heard background noises, transforming them into meaningful “notes.”

7. Silence Is Full, Not Empty

[22:52–24:47]

• When people conceive of silence as a void, they may fill it with anxious thoughts.
• Silence, as revealed by both experiments and art, is a positive sensory experience—“not nothingness. It’s full of noise.”
• “There can be beautiful silences. There can be awkward silences. There can be really powerful silences.” — Raja Goh [23:56]
• “Silence itself is a state of experiencing the world… they’re beautiful in their own right. And part of the wonder of being human is being able to experience them and appreciate them.” — Erin Westgate [24:15]

Notable Quotes & Memorable Moments

• “They said things like brushing their teeth was better.” — Erin Westgate [02:00], on how participants disliked pure silence
• “People actually do something that’s painful rather than simply sit in silence.” — Erin Westgate [03:34]
• “How can something that’s nothing do so much?” — Noam Hassenfeld [03:41]
• “There is a genuine experience of silence … there’s something it’s like to experience silence.” — Raja Goh [05:53]
• “That just felt good, right? It’s the same exact feeling. Like the single silence feels way longer than the other two.” — Noam Hassenfeld [10:03], on experiencing the silence illusion
• “Our brain isn’t just editing sounds. It’s editing silence.” — Noam Hassenfeld [11:06]
• “I'm screaming in a room, and it's really quiet. That's really weird.” — Noam Hassenfeld [16:59], inside the anechoic chamber
• “There’s no way to stop the reception of sound. If you stop the sounds from the outside, then what you hear are the sounds that are coming from the inside.” — John Cage [19:01]
• “There is no such thing as silence.” — William Marx [22:52]
• “There can be beautiful silences. There can be awkward silences. There can be really powerful silences.” — Raja Goh [23:56]
• “Silence itself is a state of experiencing the world…they’re beautiful in their own right. And part of the wonder of being human is being able to experience them and appreciate them.” — Erin Westgate [24:15]

Timestamps for Important Segments

• [01:25] - Erin Westgate explains her original silence experiment
• [02:23] - Participants opt for unpleasant sounds over silence
• [02:56] - People choose mild electric shocks over silence
• [05:06] - Raja Goh describes the “palpable” silence at the symphony
• [06:19] - Introduction to the “One Is More” auditory illusion
• [08:58] - Raja applies the illusion to silence
• [10:03] - Noam’s firsthand reaction to the “silence illusion”
• [13:59] - Noam visits Cooper Union’s anechoic chamber
• [16:12] - Description of the chamber’s “thick” silence and adaptation
• [18:42] - John Cage’s anechoic revelation
• [19:18] - Performance and impact of Cage’s 4’33’’
• [22:52] - “There is no such thing as silence”
• [23:56] - The varieties and emotional weight of different silences
• [24:15] - Erin Westgate on appreciating silence as valuable

Closing Reflections

The episode reframes silence as not an empty void but an active, potent presence that we “hear” just as much as sound. Silence can feel oppressive, healing, awkward, or beautiful. Our brain detects and processes silence in complicated ways, and even our deepest experiences of “nothing” are full—if not with external noise, then with the unignorable sounds of our own bodies and minds. As John Cage’s 4’33’’ shows, the meaning and texture of silence are shaped by context, intention, and attention.

Noam invites listeners to practice their own “4’33’’”: to simply listen to the unique silence around them—wherever, whenever. “Let’s listen to the silence and see what we can hear.” [25:07]

Next episode teaser:
“How a blind astronomer learned to listen to space.” [31:18]

If you enjoyed this summary or the themes of the episode, consider recording your ‘local’ silence and sending it to the Unexplainable team!