Is laughing when we’re nervous or uncomfortable a common reaction?

When it’s the least appropriate, probably even rude, some people have no control over the giggles.

One of our producers on the weekend witnessed a lady, not paying attention, run full speed into a table, he immediately burst out into laughter and then went to her aid.

But why the laughter first?

Dr Steve Ellen is a Professor of Psychiatry at the University of Melbourne and joins John and Garry...