laurawheeler writes: "If you see someone having a vigorous scratch then does this make you feel itchy too? There have been many anecdotes to suggest that observations or thoughts of itchiness make people feel itchy themselves. For instance, it can be quite hard for medical students to sit through dermatology classes without engaging in scratching at some point! However a new study published in PNAS this month explores this systematically for the first time and provides the first evidence for the neural basis of socially contagious itch. It also considers why some people may be more prone to it than others."