So much for faking it until you make it.  Apparently if you really don’t get someone’s sense of humor but you laugh anyway new research shows their brain can tell you really don’t think it is funny.

Turns out a group from the Royal Holloway University in London measured the brains responses of volunteers while experiencing genuine laughter watching YouTube clips. The results showed experiencing genuine laughter lit up the parts of the brain that processes positive emotions and happiness. They then compare the reactions to laughter that was faked to compare brain reactions to disingenuous laughter.

Turns out when your brain hears laughter that isn’t genuine it activates a part of the brain that tries to figure out the person’s emotional condition and why they are faking the reaction.

Lead researcher Dr McGettigan said: 'It's fascinating to consider the way our brain is able to detect genuine happiness in other people. 'Our brains are very sensitive to the social and emotional significance of laughter.’

So what’s the difference? For health reasons note that genuine laughter can boost your immune system up to 40% according to a study done at Indiana State University.