STUDENTS facing exams this month, take heart: your companions can smell your fear, and they empathise.

That’s the implication of a study by Bettina Pause at the University of Dusseldorf, Germany, and colleagues. They put absorbent pads under the armpits of 49 university students an hour before they took their final oral exam and again as the same students exercised. Another set of students then sniffed the sweat samples while having their brains scanned.

None perceived a difference between the two types of sweat, but the pre-exam sweat had a different effect on brain activity, lighting up areas that process …