Answer:
Being egocentric -- thinking that oneself is the center of things -- should be pretty straightforward. However, it would seem that the 'intellectual' version of this can be interpreted in two ways. Perhaps conventionally it is understood in one way or the other. The key distinction, however, seems to be that one either "thinks of oneself as the center of things BECAUSE of their intelligence", OR "one thinks of oneself as the center of everything intellectual". I hope this helped.
Sophile