Musical notation has been in existance for at least a thousand years, ranging from early instrument fingering diagrams to the modern staves notation that is so familiar to us nowdays. The ability to read notation is undoubtedly a great advantage for most musicians but it can also be a prop behind which a musician can hide and never bring out their full potential as a performer.
Jazz originally developed as a aural art and to this day the traditions still continues. Musicians who have learnt a piece by ear will invariably remember music for a considerably longer period than had they learnt the same piece by reading notation. This is not to say that notation does not play a very important part in most forms of western music but it's use must be balanced against the drawbacks.
Ideally, students need to develop the art of learning by listening and then playing back what they have heard in addition to absorbing melody through written notation. This will allow the student to develop as a much more rounded and accomplished performer.