Origins of Handedness Uncovered

There are any number of old wives tales and statistics surrounding left-handedness, and until now it was widely debated whether hand preference is something we learn over time or if it has to do with neurological wiring from birth. However, a new study recently published in eLife argues that hand preference has “nothing to do with our brains or our neurological development,” according to IFLScience.com. Instead, the international team of researchers believe left- or right-handedness “is actually ingrained in your biological workings from before you were born, but in the form of a particular hubbub of gene activity in the spine, not the brain.”

Prior to this research, it was believed “that gene activity in the brain, depending on which hemisphere shows the most activity, defines whether or not someone is right- or left-handed.” Now, this team has uncovered asymmetry which occurs long before the motor cortex “is ‘wired up’ to the spine,” Robin Andrews wrote. This asymmetry ultimately determines whether a person will be right or left handed and was identified by carefully monitoring the spinal cord development of growing babies in the womb between the eighth and twelfth weeks of pregnancy. 

The team also determined what causes this asymmetry. Apparently, they are influenced by environmental factors that impact that baby inside the womb. However, more research needs to be done in order to determine exactly what these environmental factors might be.