New Scientist has posed a question that sounds simple and quickly becomes complicated: what is an itch, and why can a simple touch calm it? The query appears in the magazine's Last Word series, where readers rather than staff writers supply the science.
The question splits cleanly in two. First, there is the itch itself — the unpleasant sensation that drives us to scratch. Second, there is the odd fact that stroking or touching the skin can sometimes relieve it. Both puzzles are put to the magazine's audience rather than to a single expert.
The responses, as printed in the feature, are the readers' own efforts to explain the science behind a shared, everyday experience. What emerges is less a single definitive account and more a collective attempt, from the people who actually asked the question, to reason it out.