Humans are fundamentally social animals. Our social nature means that we interact with each other in positive, friendly ways, and it also means we know how to manipulate others in a very negative way.

Neurophysiologist Katherine Rankin at the University of California, San Francisco, has also recently discovered that sarcasm, which is both positively funny and negatively nasty, plays an important part in human social interaction.

So what?

I mean really, who cares? Oh for God's sake. Don't you have anything better to do that read this column?

According to Dr. Rankin, if you didn't get the sarcastic tone of the previous sentences you must have some damage to your parahippocampal gyrus which is located in the right brain. People with dementia, or head injuries in that area, often loose the ability to pick up on sarcasm, and so they don't respond in a socially appropriate ways.