Why Are Most People Right Handed?
Are you a “southpaw?” If so, you’re in a minority; only about 10% of the human population is left handed.
(Much smaller minorities are ambidextrous, capable of using both hands equally well, and mixed-handed, meaning you find some tasks easier with the left hand and others with the right).
All mammals show side preferences. We have a good model for this in an animal that we use for tasks and who’s side preference matters: The horse.
Are Horses Right-Hooved?
In horses, side preference manifests as a greater willingness and ease to turn in one direction over the other. The majority of horses have a “weak side,” which has to be strengthened with training and exercise (something they aren’t always happy about).
Side preference is stronger in some animals than others.
However, there’s a clear difference between horses and humans…and this difference is the same for other mammals.
Horses split about 50/50 as to which side they prefer. There is a slight preference for turning left, but this may reflect animals with a very low side preference and the fact that in most traditions, animals are always worked from the left side (Spain is a peculiar exception here).