Mentality of a person who repeatedly shifts focus from one subject of study to another

I am looking for a word which describes the mentality of a person who is inspired to learn something and starts studying, but then quickly moves on to another subject. Such a person shifts focus from one subject to another without making an in-depth study of any one subject.

You should not have a _______ mentality, shifting from subject to subject.

It would be like trying to find water by digging a well. If you dig ten feet deep and don’t find water, you move to another location, dig another twelve feet, don't find water, again move to another location, dig another fifteen feet, and so on. By this time, you have dug seventy-five feet deep maybe, spread across five or six locations, but you still haven't found water because you have not dug in one place. Maybe you would have gotten water if you had dug twenty-five feet deep, but you will never get to this depth because you move from place to place, site to site.

What is this type of mentality called?

Solution 1:

Dilettante: "a person having a superficial interest in an art or a branch of knowledge"; or

Dabbler. To dabble is "to work or involve oneself superficially or intermittently especially in a secondary activity or interest < dabbles in art >."

Solution 2:

You might say the person is fickle.

Fickle: changing frequently, especially as regards to one's loyalties or affections

While this word is commonly used to describe someone who frequently switches loyalties, take a look at this example from Oxford Dictionaries Online.

Now the impression is of a fickle politician who has lots of ideas but no staying power to see them through.

You might also consider flighty.