Best research EVER: Students yawn not because they are bored, but because their brains are ON FIRE with my lectures! That may be an overstatement, but the research conclusion is interesting...

Yawning is body's "thermostat"

""Yawning is not just a sign of tiredness or boredom – it is the body's method of keeping our brain cool, scientists have found.

When the head begins to heat up, yawning acts as a natural "thermostat" by allowing cool air to rush in and bring the brain back down to a healthy temperature, research suggests.

Brain temperature is influenced by the amount of processing the brain is having to do, the temperature of the blood and the rate at which it flows to the brain. ""