Right hand or left? If you have a preference, it may be because you walk upright

Hand-painting
Toddlers begin to prefer their left or right hand when they start walking

Graduating from a crawler to a toddler is a significant developmental milestone for every child. Tentative steps turn into more confident toddles, and soon they are scampering off in whatever direction their insatiable curiosity takes them. At the same time as kids are learning to place one foot reliably after the next, significant changes are also occurring in how they use their hands. Whereas crawlers are happy to grab with either hand, by the age of three, a preference for the left of right hand has usually been established. The transition from crawling on hand and knees as a quadruped, to walking bipedally on two feet, creates a strong bias that can be seen both at the individual level – the vast majority of us has a preference for one side over the other – and at the population level – only around one in 10 people are left-handed. So, too, if we look at handedness from an evolutionary perspective. In mammals, the more upright the posture, the more likely that the species has a left- or right-hand bias. Ambidexterity, it seems, remains the preserve of quadrupeds. Continue reading “Right hand or left? If you have a preference, it may be because you walk upright”