What is the origin of, "Are you a mouse or a man"? Have a bet riding on it.Shakespeare?

The title of John Steinbeck's novel, Of Mice and
Men, is derived from a line in the poem, To a Mouse, on Turning her
up in her nest with a plough, written by Scottish poet Robert Burns in 1785.
Legend has it that Burns wrote the poem whilst still holding the plough with which he
had accidentally destroyed the mouse's winter-nest.

The
relevant lines in the poem are:

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The best-laid schemes o' mice an'
men
Gang aft
agley,

Burns is commenting on
the fact that even the best made plans of men (meaning humankind) who bestride the
world, and in contrast, those of tiny, timid, feeble mice, go awry - suggesting that no
one, no matter who or what you are, can ever be quite certain of the outcome of one's
endeavors. The poem does not draw a distinct contrast between man and mouse related to
strength, power or conviction as the expression, man or mouse
does.

The expression was never
used by William Shakespeare and cannot be traced to any of his texts. The contrast was
first used in 1620 but there is no accurate record of who, or exactly in which context,
it was employed. The expression has, however, become popular since then and is now
rooted in English vernacular as a somewhat cliched idiomatic
expression.

One may assume that the
expression's origin is derived from the behavioural mannerisms of mice. They always seem
anxious and timid. An observation of their continuously twitching noses and whiskers as
well as their uncertain movements and quick scurrying to avoid being noticed, as well as
their miniscule size, confirms this notion.