Interested to know what this means. When people ad lib (make up) a tune by whistling or humming or la-la-la-ing, they tend to gravitate naturally towards a pentatonic or major scale; a melodic minor is quite unnatural unless you've been taught it.
generally i use harmonic minor or pentatonics when it comes 2 rock or metal.
But i wanna try other modes n scales so it will expand my guitar playing...