What makes a person right or left-handed has, up until now, been something of a mystery to us.
And while we know genes play a part, thanks to some research carried out by experts at Ruhr University Bochum in Germany, more details have emerged as to when – and why – you develop either a right or a left-handed tendency.
According to the research, the subconscious preference develops as early as eight weeks into the pregnancy when, according to Mother and Baby, you’re only the size of a raspberry or a grape. Madness.
In fact, ultrasounds from week 13 of a pregnancy have revealed some babies already have a thumb-sucking preference dependent on which side is more dominant. Given you don’t start learning to write until you’re three or four, that’s some head start in the right/left-handed stakes.
And while it’s previously been believed that it’s the brain that decides if you’re a righty or a lefty, this new research reveals it’s actually your spinal cord. While the motor cortex in your brain does initiate arm and hand movements, it only sends a signal to the spinal cord, which turns that into a physical motion. Therefore, the side of the body a command is physically carried out on is determined by the spinal chord.
‘These results fundamentally change our understanding of the cause of hemispheric asymmetries,’ the study’s authors noted.
Interesting. So it’s all in the spinal cord. Now we just need to find out why so many more people are right-handed as opposed to left-handed, but we’ll save that science lesson for another day.
