From the time we pick up a chunky crayon and start scribbling as children, it begins to become clear whether we’re right- or left-handed. But what makes one hand dominate? And why are left-handers in the minority?

To find out more, Adam Rutherford and I decided to investigate the science and history behind human handedness for the BBC Radio 4 series The Curious Cases of Rutherford & Fry.

It soon became clear that there was more to the question than we thought: for example, I had never realised that our body is lopsided in other ways too. Take your eyes, for instance. You can tell whether you are right or left-eyed by trying the following test:

Hold a thumb out at arm’s length in front of you. First, look at it with both eyes, then try covering each eye in turn. Your strongest eye is the one which gives the nearest picture to stereo vision.

Similarly, you can test your ears: which ear would you naturally use on the telephone? Or to listen, clandestinely, against a wall?