Righthandedness

The same writer expresses his doubt as to monkeys showing any tendency to righthandedness.

That this should become prescriptive is by no means to be taken for granted, since eating aided by a knife in the right hand to cut bite-size fragments off the food must usually, given righthandedness, involve or have involved handling the food with the left hand, and the use of knife and fork has resulted in a European (cum British) norm of putting food into the mouth with fork held in the left hand, as distinguished from the American norm of using the fork held in the right hand.

Compared with general population samples under the same criteria, and with their own second-degree relatives, non-righthandedness is in fact more frequent in twins and their first-degree relatives.

Intuitively, a surface is orientable if there the exists a sense of “righthandedness” and “lefthandedness” that can be defined consistently throughout the whole surface.