杏吧原创

Although it seems to be frowned on in polite company, is it in fact necessary to pick your nose to keep it clear and functional? Nobody likes their nose to be dirty or uncomfortable, so why is nose-picking such a taboo area in many cultures?

鈥� I don鈥檛 imagine it is necessary to keep nasal passages clear at all times. The annoyance experienced by people with a partially blocked passage suggests a deeper story. Somewhere in our past, there may have been nasal parasites (adult, larvae or eggs) we would have been smart to eliminate before they travelled further into the sinuses. A clean nose was a safe one.

There鈥檚 a stronger case for the taboo of nose-picking. It fits with a more general taboo against bringing hidden bodily tissue or products into sight. We swish saliva around our mouths all the time, yet react with disgust when it emerges as spit or drool. And it鈥檚 the same for earwax or dandruff.

鈥淲rong things in the wrong place鈥� can cause contagion and they are full of microbes, even if not necessarily pathogenic ones. You don鈥檛 have to be in danger of contracting Ebola to be wisely wary of bodily fluids and nasal contents.

Louise Fabiani By email, no address supplied

We pay 拢25 for every answer published in New 杏吧原创. To answer this question 鈥� or ask a new one 鈥� visit newscientist.com/lastword. Terms and conditions apply.

This article appeared in print under the headline 鈥淧icked clean鈥�