You know that old philosophical question: How do I know we both see the same colour when we look up at a blue sky? Some research just published asks the same type of question, but of our sense of taste.
The study shows that our tongues respond quite differently to a particular bitter taste synthesised in the laboratory. In fact, some people are a 1,000 times more sensitive to this chemical than others. This seems to be a direct result of genetic differences between us.