There is a myriad of factors involved in determining shyness.
For one thing, socially closed functions will make a person more 'shy' than socially open ones.
On the other hand, the same can be said of internal functions as compared to external ones.
This in mind, the most 'shy' function has to be intuition; thinking and feeling are moderate on this account, while sensation is without a doubt the least 'shy' of functions.
So if we add I/E to the mix, we can place all of the eight functions on a scale denoting their 'confidence' factor:
(using object/field instead of extroversion/introversion here to avoid confusion with internal/external)
socially open, external, object; 1 + 1 + 1 = 3
socially closed, internal, object; 0 + 0 + 1 = 1
socially closed, external, field; 0 + 1 + 0 = 1
socially open, internal, field; 1 + 0 + 0 = 1
socially closed, external, object; 0 + 1 + 1 = 2
socially open, internal, object; 1 + 0 + 1 = 2
socially open, external, field; 1 + 1 + 0 = 2
socially closed, internal, field; 0 + 0 + 0 = 0
least shy ---> most shy
[[
], [
,
,
], [
,
,
], [
]]
The assumption here is that each of the three dichotomies contribute equally to how 'confident' an impression a function makes.
Of the backbone dichotomies introversion/extroversion seems to be the only one that makes a difference, though J/P and static/dynamic will have a profound effect on which situations a person is shy or confident in... (personally I'm
very shy whereever the dynamic element is dominant.)