Podcast Summary: ReThinking: The Science of Taste and Smell with Rachel Herz

Podcast: ReThinking
Host: Adam Grant (with guest neuroscientist Rachel Herz and co-host Alison Grant)
Release Date: July 22, 2025

Episode Overview

In this engaging episode, Adam Grant explores the complex worlds of taste and smell with Dr. Rachel Herz, a neuroscientist specializing in olfaction and author of Why You Eat What You Eat and The Scent of Desire. Joined by guest co-host and novelist Alison Grant, the trio delves into the science behind supertasters, genetic influences on our palate, the powerful relationship between smell and emotion, and society’s frequent underappreciation of the sense of smell. Adam’s personal aversions and Alison’s extraordinary sense of smell make the conversation both educational and lively.

Key Discussion Points & Insights

1. What Makes a Supertaster? (03:08–07:55)

• Supertasting Explained:
  Rachel explains the genetics behind supertasters: having two specific alleles gives a person more taste buds, making flavors—especially bitterness—far more intense.

  • Quote [04:27, Rachel Herz]:
    “Supertasters live in a neon taste world, so everything is more intense.”

• Genetics & Family Ties:
  Taste perceptions are inherited; Adam notes his grandmother hated chocolate, suggesting a family lineage of supertasting.

  • Quote [08:00, Rachel Herz]:
    “This is genetics that goes through the family tree. You probably can't escape it anyway.”

• Counterintuitive Salt Preference:
  Supertasters often prefer adding salt because it blocks bitterness; Adam, however, doesn’t share this trait.

2. The Evolutionary and Health Sides of Taste (07:55–13:52)

• Why Bitter Is Bad and Sweet Is Good:
  Evolution primes us to avoid bitterness (often toxic) and crave sweetness (energy-rich carbs):

  • Quote [08:52, Rachel Herz]:
    “We are hardwired, actually, to find bitter bad and sweet good.”

• Health Implications:
  Supertasters often avoid nutritious bitter foods and may overuse salt, increasing health risks (e.g., colon cancer, hypertension). Non-tasters, conversely, are less likely to become addicted to substances like tobacco or alcohol due to higher aversion thresholds.

3. Taste and Smell: Intertwined but Distinct (14:00–19:26)

• Scent and Flavor Connection:
  Adam’s reaction to fishy smells and certain foods produces intense aversion, which Rachel attributes to receptor gene variants.

  • Quote [14:31, Adam Grant]:
    “When you cook salmon, sometimes I have to leave the house because it's just overwhelmingly bad.”

• Context Effects:
  Perception of smell changes dramatically based on context and expectations—demonstrated by an experiment where a single scent received polar opposite reactions based on how it was framed.

• Counterintuitive Food Examples:
  Some foods (e.g., durian, stinky tofu) may smell unpleasant but taste good, underscoring the complexity of olfactory and taste interactions.

4. Undervaluing Our Sense of Smell (22:30–28:41)

• Social Survey Insights:
  A significant portion of college students would rather lose their sense of smell than their cell phone or hair.

  • Quote [22:46, Rachel Herz]:
    “Still, 25% of college students would rather lose their sense of smell than their cell phone. 50% actually would rather lose their sense of smell than their hair.”

• True Value of Smell:
  Smell is intimately connected with emotion, memory, and even cognitive/spatial abilities. Long-term loss can lead to serious depression and “losing oneself.”

  • Quote [26:31, Rachel Herz]:
    “I think that they should get between 90 and 100% of their net worth [if they lose their sense of smell]. ... Severe depression can actually become something that people develop as a function of losing their sense of smell.”

5. The Role of Smell in Attraction & Relationships (28:53–30:41)

• Smell and Human Connection:
  Rachel notes that olfaction often subconsciously influences attraction and can even be a dealbreaker in relationships.

  • Quote [28:53, Rachel Herz]:
    “If I had not liked how he smelled, that would have been a barrier for us ever getting together.”

• Every Person Is an Olfactory Fingerprint:
  Each individual’s scent is genetically unique, and each nose’s receptor composition is slightly different, explaining vast differences in sensitivity.

6. Unique Abilities and Medical Diagnostics (30:41–34:01)

• Super Smellers:
  Alison once detected her son’s ear infection by scent, which Rachel attributed to a higher number of certain scent receptors and a learned baseline. Historically, doctors used such skills in clinical diagnosis.

• Smell and Illness:
  Diseases can alter body or breath odor, and some people (and dogs) can reliably detect such changes.

7. Lightning Round Insights (36:04–39:10)

• Mind over Mouth:
  Visual context, like the color of a plate or bowl, can meaningfully alter perceived flavor intensity.

  • Quote [36:24, Rachel Herz]:
    “The color of the plate affects how food tastes.”

• Dream Dinner Guest:
  Rachel would love to have Julia Child at a dinner party.

• Handling Body Odor Diplomacy:
  Rachel: If you suspect there’s an underlying medical reason, broach the topic with care or medical empathy.

8. Final Reflections: Scent and Identity (39:10–40:05)

• Self-Image through Scent:
  Rachel describes how she uses perfume to enter a specific “mental space,” even on audio-only calls.

  • Quote [39:29, Rachel Herz]:
    “I smelled up for you instead of dressed up.”

• Looking Ahead:
  Playfully, the group speculates about future technology sending and receiving scents—a potentially polarizing idea.

  • Quote [40:44, Rachel Herz]:
    “I actually think this is going to be something that is in the near future...”

Notable Quotes & Moments with Timestamps

• Rachel Herz on Super Tasting:
  “Supertasters live in a neon taste world, so everything is more intense.” (04:27)

• Adam Grant’s Familial Super Tasting:
  “My grandmother hated chocolate. So it seems to go back a couple generations.” (07:55)

• Rachel on Evolutionary Taste Preferences:
  “We are hardwired, actually, to find bitter bad and sweet good.” (08:52)

• Adam’s Aversion to Fish:
  “When you cook salmon, sometimes I have to leave the house because it's just overwhelmingly bad.” (14:31)

• Rachel on the Value of Smell:
  “I think that they should get between 90 and 100% of their net worth. Because what people don't understand: their entire life was turned upside down in tremendously devastating ways.” (26:31)

• On Scent in Relationships:
  “If I had not liked how he smelled, that would have been a barrier for us ever getting together.” (28:53)

• Alison’s ‘Super Nose’:
  “He was in his crib and woke from a nap ... I could just smell it. He has an ear infection.” (30:59)

• On Visuals Affecting Taste:
  “The color of the plate affects how food tastes.” (36:24)

• Rachel on Perfumery and Mindset:
  “I smelled up for you instead of dressed up.” (39:29)

Timestamps for Important Segments

• [03:08] – Adam’s food aversions and introduction to supertasting
• [07:55] – Genetics of taste; family history
• [08:52] – Evolutionary basis for sweet vs. bitter
• [13:47] – Health implications for supertasters
• [14:31] – Taste-smell connection; fish aversion
• [17:46] – Disparity between smell and taste (stinky tofu, durian, coffee)
• [22:46] – Undervaluing sense of smell, survey results
• [26:31] – Emotional, social, and cognitive importance of smell
• [28:53] – Scent and romantic relationships
• [30:59] – Alison detects son’s ear infection by smell
• [36:04] – Lightning round: plate color, dinner guest, body odor etiquette
• [39:29] – Perfume, personal scent, mental space
• [40:44] – Futuristic speculation: transmitting scents digitally

Conclusion

This episode weaves together science, personal anecdotes, and cultural reflection, illustrating why our taste and smell deserve more appreciation—and how they shape our daily choices, relationships, and memories. Rachel Herz’s clear, accessible explanations and Adam’s candid personal stories make for an episode as delightful as a favorite flavor (or scent!).