Why do we itch?
BBC Learning English's 6 Minute English asks why we itch, and why itching can feel contagious. Drawing on the work of itch specialist Sonja Stander and psychologist Dr. Henning Holler, the episode (aired 2026-09-24) explains the biological purpose of itching and the odd psychological phenomenon of catching an itch just by watching someone else scratch.
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What this episode answers
What biological role does itching play in the body?
Itching functions as a warning system that alerts the body to things that shouldn't be on the skin, such as parasites or bits of plant matter, prompting us to scratch them off; it plays a defensive role in protecting the body from threats.
Is scratching actually a beneficial thing to do?
Yes — the article explains that scratching is the correct response to the itch alarm, since it can actually remove foreign matter like parasites or plant debris from the skin, making it a beneficial act rather than just an unpleasant habit.
Can just watching a video of someone scratching make you itchy too?
Yes — in Dr. Henning Holler's experiment, participants who watched a video of someone scratching began scratching themselves spontaneously, without being asked or even realizing it, showing that watching alone can trigger an itch.
What does it mean to say "you can catch a scratch"?
It means that, just as you can catch a cold from someone else, simply watching another person scratch can make you feel itchy and start scratching yourself without thinking about it — itching has a contagious quality.
What was Dr. Henning Holler's guests on Crowdscience listening to when they heard the scratching sound?
The sound was someone scratching their beard. Guests reacted with comments like "it sounds like hairy skin" and "it seems like a beard," and arrived at the correct answer.
What is an itch?
An itch is that uncomfortable sensation on the skin that makes you want to scratch it with your nails or fingers. Host Neil shares a recent experience of a mosquito bite that left him unbearably itchy, while Georgie confesses that her wool jumper makes her desperate to scratch. It's a sensation everyone experiences regularly — and, as it turns out, there's real science behind it. The episode brings in two experts to walk through the biological and psychological sides of itching.
The biological role of itching — expert Sonja Stander explains
Sonja Stander, an itch specialist who appeared on the BBC World Service programme Crowdscience, explains the protective function of itching in simple terms. When your skin itches, you reflexively scratch that spot. This action helps remove things that shouldn't be on the skin, such as parasites or fragments of plants. A parasite is an organism that lives on another animal and feeds off it, and when one attaches to the skin, it can damage the tissue there. Itching, Stander explains, is an alarm system that detects such threats and protects the body, and scratching is the correct response to that alarm. Crowdscience presenter Anand Jagatia introduces the topic by saying "there's lots of science to unpack here," prompting Stander's explanation. Here, "unpack" means to explain something in detail by breaking it down — and it's one of the vocabulary words the episode highlights.
Itching is "contagious" — Dr. Henning Holler's research
Dr. Henning Holler, who studies the psychology of itching, ran an experiment to find out whether simply watching footage of someone scratching could make people itchy themselves. When participants were shown a video of someone scratching, they spontaneously began scratching their own bodies. They weren't asked to, and they weren't even consciously aware of doing it — it happened naturally. Based on this result, Holler concludes that "you can catch a scratch." Here, "catch" is used the same way as in "catch a cold," showing that itching can spread just from watching someone else's behavior. If you've felt a bit itchy reading this, that may be exactly the phenomenon at work.
Quiz answer: what was being scratched?
The quiz question Neil posed at the start of the episode was: what was being scratched in the sound that Dr. Henning Holler played for his guests on Crowdscience? The choices were A) an arm, B) a beard, or C) jeans. Georgie guessed B) beard, based on her intuition that the sound seemed "hairy," and her guess turned out to be correct. The guests listening on Crowdscience had similar reactions, describing it as "the sound of hairy skin" or saying "it seems like a beard," and arrived at the right answer.
Six vocabulary words from this episode
The episode also covered six English vocabulary items: **itch** (the noun) and its adjective form **itchy**; **scratch** (to rub your nails against the skin); **unpack** (to explain an idea or concept in detail); **parasite** (an organism, animal or plant, that lives on another organism and feeds off it); **spontaneously** (doing something naturally, without being prompted by anyone); and **catch** (to "come down with" something like an illness, as in catch a cold). These six words are practical terms that come up often in scientific conversations and articles alike.
Takeaways
- Itching is a biological defense mechanism for removing parasites and foreign matter from the skin, and scratching serves the clear purpose of protecting the body.
- Dr. Henning Holler's experiment demonstrated that people spontaneously start scratching just from watching video of someone else doing it, showing that itching can spread visually — it's "contagious."
- This episode's key vocabulary was itch, scratch, unpack, parasite, spontaneously, and catch — six words useful across everyday conversation and scientific contexts alike.
This article is edited from a machine transcript of the first 30 minutes of the episode. It is not an official summary — please listen to the episode itself.