Podcast Summary: Nudge with Phil Agnew

Episode Title: How sights, smells and sounds alter what you buy
Air Date: September 29, 2025

Overview

In this episode of the “Nudge” podcast, host Phil Agnew explores the fascinating ways that our senses—sight, smell, and sound—shape our perceptions, decisions, and buying behaviors. Drawing on a wide range of psychological research and real-world case studies, Agnew is joined by experts such as Professor Charles Spence and Professor Adrian North to reveal how subtle environmental cues can drastically influence everything from taste to the amount we spend in stores.

Key Discussion Points & Insights

1. The Power of Packaging and Visual Cues

• Coca Cola’s White Can Experiment
  • In 2011, Coca Cola changed its iconic red can to white to raise awareness for polar bear conservation. Despite the formula staying the same, consumers reported the Coke tasted different.
  • Quote (Phil Agnew, 00:21): “The drink inside wasn’t changed at all. But the new color of the can changed how consumers perceived the taste.”
  • Some consumers insisted the new can actually made the Coke taste worse, prompting a quick return to the red can.
• Why?
  • Visual cues, especially color, unconsciously influence perception and expectation.
  • For products like chocolate and drinks, even subtle changes to shape and color can alter perceived taste and quality.

2. Sound Symbolism & Cross-Sensory Associations

• Kiki and Bouba Experiment
  • Psychologist Wolfgang Köhler’s classic experiment demonstrates that people universally associate angular shapes with harsh, “spiky” sounds (Kiki) and rounded shapes with soft, “rounded” sounds (Bouba), regardless of language or culture.
  • Charles Spence applied these insights to advising brands (e.g., making chocolate bars more rounded to make them taste sweeter).
  • Quote (Adrian North, 03:05): “Bitterness is more angular and is kiki, instead... if you want to make your chocolate taste sweeter, make it rounder...”
  • Cadbury’s redesign: Rounded Dairy Milk chocolate bars led to customers saying it tasted “creamier and more sweet”—with no change in ingredients.

3. How Music Shapes Buying Decisions

• Wine Shopping Study (Adrian North)
  • Playing stereotypically French or German music near supermarket wine shelves significantly increased sales of wines from the corresponding country—even though price and wine sweetness were held constant.
  • Quote (Guest Expert, 05:46): “When we played the very stereotypically German music, then German wine outsold French by five bottles to one.”
  • Shoppers denied being influenced by music (86% said it had “no effect”), but their choices told a different story.
  • This principle generalizes: music matched to cuisine in cafeterias increased sales of related national dishes (flamenco for paella, Italian music for chicken parmesan).
• Music in Advertising
  • Background music that fits a key product attribute enhances memory for that feature.
  • Quote (Guest Expert, 07:23): "...when the music fits a particular aspect of the product, people are more likely to recall that specific feature of the product itself."

4. The Impact of Scent

• Scented Retail Environments
  • Floral scents made customers willing to pay more and increased self-reported purchase intent.
  • Iconic “new car smell”: Rolls Royce uses custom scents to evoke a sense of luxury and freshness after servicing cars, leaving owners convinced their car drives and feels “like new.”
  • Certain scents (e.g. synthetic coffee) at petrol stations or supermarkets can dramatically boost sales—but large effects in industry studies may not be as reliable as independent research.

5. The Illusion of Sound in Product Experience

• Engine & Appliance Volume
  • Louder engine or vacuum noises make cars seem faster and vacuums seem more effective, even when objective performance is the same.
  • Study: Lowering the car sound by 5 decibels led viewers to underestimate its speed by 10%.
• The “Loudness Effect” in Sports
  • In tennis, artificially increasing the “thwack” of the ball convinces viewers the shot was more powerful.
  • Quote (Phil Agnew, 11:31): “The sound of the ball’s contact with the racquet was technically irrelevant to the task, but it changed where they perceived it to be hit.”

6. Multi-Sensory Marketing in Action

• Dunkin Donuts Seoul Campaign
  • Buses equipped to emit coffee aroma when their jingle played.
  • Resulted in a 16% increase in store visits and a 29% rise in coffee sales.
  • Quote (Phil Agnew, 16:21): “Jingles combined with scents made Koreans buy more coffee.”

Notable Quotes & Memorable Moments

• On Cross-sensory Influence:
  “Your car will seem faster if it's louder and red. It'll drive smoother if it’s got that new car smell. A tennis player seems more powerful if they grunt a little louder.”
  — Phil Agnew (20:46)
• On Consumer Denial:
  “86% of the customers surveyed after said the music had absolutely no effect on their choice.”
  — Phil Agnew (06:34)
• On Music and Spending:
  “He found that when he played the fast music, people took less time to get from point A to point B...But...when they played slow music, people take longer to go around the store...they ended up spending more.”
  — Guest Expert (17:16)
• On Time Perception and Experience:
  “The people who have heard eight songs think they've been there for longer because eight things have happened.”
  — Guest Expert (19:12)

Timestamps for Key Segments

• 00:00 — Coca Cola’s white can packaging experiment
• 01:56 — Kiki and Bouba sound-shape associations
• 03:05 — Synesthetic links in food perception (Cadbury Dairy Milk case)
• 04:17 — Wine purchase study: music and nationality influence
• 07:23 — Matching music to ad content boosts recall
• 08:45 — Scent's impact on purchases (flower-scented sneakers, new car smell)
• 10:56 — Sound illusion: cars, vacuums, and tennis
• 12:53 — Multisensory Dunkin Donuts jingle campaign in Seoul
• 17:16 — Milliman’s study: How store and restaurant music speeds/tempo affect time and spending
• 19:12 — Counting “events” changes perception of time spent in a setting

Applied Takeaways for Marketers

• Visuals matter: Product color and shape can alter taste and purchase intent.
• Align music with context: Use music that fits product origin, desired feature, or dining experience to bias customer choices and spending.
• Use scent to trigger desire: Pleasant smells enhance perceived value and can drive sales.
• Leverage sound design: Louder or "richer" product noises (within reason) boost perceived performance.
• Combine senses: Multi-sensory marketing—like synchronized jingles and scents—amplifies behavioral effects.
• Design for time: Store and restaurant pacing (via music tempo) can increase dwell time and spend.

Recommended Reading:

• “Sense Hacking” by Charles Spence

Referenced Studies:

• Wolfgang Köhler’s Kiki/Bouba experiment
• Adrian North’s wine/music study
• Ronald Milliman’s research on music tempo
• Dr. Alan Hirsch’s scent studies

Overall Tone:
Engaging, conversational yet scientifically grounded, with practical marketing applications woven throughout.

This summary preserves the rhythm and signature style of the Nudge podcast, blending clear scientific insight with memorable stories and direct advice. It's ideal for marketers, product designers, or anyone curious about how to subtly shape behavior through sensory cues.