Why are crying babies so hard to ignore?

During a speech to a rally, Donald Trump initially reassured a distressed mother with a crying baby, telling her not to worry - only to change his mind.

"Actually I was only kidding, you can get the baby out of here," he said a few minutes later.

Professor Christine Parsons at Aarhus University in Denmark has done a study on reactions to babies crying.

She says primitive parts of our brains are activated by a baby's cry and that it can be very distracting when doing something complex, like making a speech.