Why do scales go up?

When you ask someone to sing or play a scale why do they always perform an ascending scale? I do this experiment often and very seldom does anyone descend.

Why is it so easy to recognize “Do-Re-Mi” from The Sound of Music as a scale even though it is very broken up, but not so easy to recognize that the theme of the Nutcracker “Pas de Deux” is a straightforward descending major scale?

Could it be that the period of early concert music, early music pedagogy and early musicology was when string instruments dominated? String instruments are, by their nature, ascending instruments and ascending scales are amongst the very first things played after open strings?

If you ask someone why they play ascending they will often reply that they were taught that way. But why were they taught that way?

We will never know the answer, but it’s an interesting question, isn’t it?