Hector the Tickle Robot, Eyeball Teeth, a Little Bit of ~Spice~ (and Neuroscience)
September 9, 2026
AI Summary
5 min readIn a 2024 study published in Nature Human Behavior, researchers surveyed 444 people across China, the Netherlands, and Greece and found that 98% of them had been tickled. More than 95% had tickled someone else. The reactions—laughter, squirming, trying to escape—were the same across all three cultures. When participants shaded in maps of where they were ticklish, the hot spots were nearly identical: armpits, neck, ribs, behind the knees, feet. The only variation came when people were asked to map where an intimate partner would tickle them—then erogenous zones like inner thighs appeared. The study reinforced a theory Charles Darwin floated: the places we are ticklish are the places we are touched least often in daily life, which makes the element of surprise—essential to tickling—more potent.
The Two Kinds of Tickling and the Robot That Standardized Them
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What you'll learn
- 1 (03:15) **Introductions & Teases** - The hosts welcome guest Priya Mani, author of *Spice*, and each offers a quick preview of their weird fact.
- 2 (04:31) **Rachel: The Science of Tickling** - A deep dive into the two types of tickling, why you can't tickle yourself, and what a new cross-cultural study reveals.
- 3 (14:02) **Rachel: The Tickle Robot & Why We Laugh** - How a standardized robot tickle helps quantify the response, and the leading theories on tickling's evolutionary purpose.
- 4 (22:48) **Rachel: Practical Tickling Insights** - A personal experiment with self-tickling and a call for respecting boundaries.
- 5 (32:23) **Laura: Eyeball Teeth on Whale Sharks** - A marine biologist drops a bombshell about tiny teeth covering the eyes of the world's largest fish.
- 6 (39:41) **Laura: Which Shark Would You Be?** - The hosts play a quick game of choosing a shark species for a day.
- 7 (44:20) **Priya: The Neuroscience of Prickly Ash** - How Sichuan pepper and its relatives create a unique tingling, buzzing, and numbing sensation in the brain.
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Show Notes
Author and food historian Priya Mani joins the show to talk about the neuroscience of spice. Plus, Laura explains why whales have teeth on their eyes (SERIOUSLY), and Rachel gets into why a tickle robot exists.
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