How long has the human race had right- or left-handed tendency?

[AndiFlatland]

I've often wondered whether our tendency towards right- or left-handed is something that has only developed in the last few thousand years, since we invented handwriting and other activities which required manual precision.
Is there any evidence to suggest that humans have always shown a preference for one or the other, and do animals display any such preference?

[RAV1D]

Your left half of your brain controls your right side of your body and your right half of your brain controls your left half of your body. one half of your brain becomes more active or stronger than the other half and this causes you to use one hand better than another, This is what I was told at high school many years ago! Don't know how true it is but I may be on the right track to helping you understanding it better!

[atalanta]

I reckon that right-handedness arose when Mothers ( homo erectus, neandethal, floresiensis, etc etc, whatever ) held their babies. It is soothing to the baby to have its head close to its mother's heart, so a lefthanded hold on the baby permits the mother to use the right hand for caring for the baby and doing all sorts of other tasks for herself.

[Ratty2E]

One of my dogs is left handed. When we were teaching him to shake a paw he always wanted to give the left, whereas his brother used the right. I would imagine all animals favour one side or the other I don't think it has just to do with humans or writing etc.

[wildwood]

Yes ratty, certainly all mammals are left or right 'handed'. If you pay notice to a horse galloping you'll see that not all will first land on the same front leg first. I've seen it in cats, dogs, and of course I am left-handed myself (kangaroo).

[redbez]

Research indicates that it seem's to be linked with which hand is most commonly licked or held near the mouth whilst in the womb.