Surely, at some point, you’ve wondered why you have the dominant hand that you do (or why you don’t have one). Dominant hands are a bit of a mystery, even after extensive research.

Take, for example, the guitar. Why do we do the seemingly easy part—strumming—with our non-dominant hand? Turns out, our dominant hands are more adept at timed tasks, like knowing when to strum a note. Our non-dominant hand is better at simply sitting and holding a pose until moving to the next one (picking the note/chord). Other actions include throwing a baseball or writing, two actions that require accurate timing and movement. 

Handedness corresponds with brain hemisphere dominance, as well. Left-handed dominance often corresponds to right hemisphere dominance, with right-handed dominance often corresponding to left hemisphere dominance (each hemisphere controls the muscles on the opposite side of the body). The right hemisphere of the brain is more responsible for visual-spatial skills and emotional intelligence. It is often associated with creativity, intuition, and qualitativeness. The left hemisphere of the brain controls language and speech. It is more associated with quantitative thinking, like logical reasoning and mathematical calculations. While the stereotypical differences between the right and left hemispheres of the brain are usually blown out of proportion, there remains something interesting about the inner workings of the brain.

The human population is about 90% right-handed, and 10% left-handed, with lefties tending to have more control over their non-dominant hand than righties. Some animals are left-handed too, with most preferring the right—but the preference is much less skewed compared to humans. This lateralism is not just hands, too. Birds have been found to tilt their heads sideways so that one eye looks at the ground and the other looks at the sky, with most birds seeming to favor tilting their head a certain way.