By Liz Seward
Science reporter, Festival of Science, York
Yawning may reveal more about a person than their boredom threshold, according to research.
Humans and other apes find yawning infectious
A susceptibility to contagious yawning may actually be a sign of a high-level of social empathy.
Although many species yawn, only some humans and possibly their close animal relatives find yawning infectious, suggesting the reason is psychological.
The University of Leeds research was presented at the British Association's Festival of Science in York.
"Contagious yawning is a very interesting behaviour," said Dr Catriona Morrison, a lecturer in psychology at the University of Leeds, who is leading the work.
"You don't need a visual cue, you don't even need an auditory cue - you can just read about it or think about it and it gets you going.
"We believe that contagious yawning indicates empathy. It indicates an appreciation of other people's behavioural and physiological state," she added.
Eyes have it
Recent neuro-imaging has shown that the same area of the brain is involved when reacting to yawning and when considering others.
The University of Leeds team carried out an experiment on students studying psychology and engineering to test this concept.
Each student was shown to an occupied waiting room where their companion was actually a researcher who yawned 10 times in 10 minutes. The scientists recorded how often the students yawned in response.
Each participant was then asked to complete a test of their empathetic skills, in which they analysed pictures of eyes and recorded the emotions shown.
The results showed that those who had succumbed to the most contagious yawning also scored higher on the empathy tests.
There was also a clear difference between the subjects studied.
Psychology students were more susceptible to contagious yawning, and scored significantly higher on the empathy test than did the engineering students.
Catriona Morrison said: "We thought that psychology students would be highly empathetic and that engineering students would be more systemised, more interested in numbers and formulas."
The results of the experiment appear to back this up, she added.