Collectors (Si-Ne users) is the cognitive tendency to connect new information (experiences & patterns) with one's accumulated array of information.
in the realms of detailed experiences (sensory information), this tendency results in a series of bridges & break-points utilizing similarity and contrast, narrowing down within one's spectrum of experience to mentally retrieve the most fitting precedent.
in the realm of patterns (abstract information), this tendency results in a multiply generations of hybrids as the new patterns mix & match with one's preexisting collection of patterns to generate new ones to then be reapplied to whichever subjects they can fit.
a preference for the first stems from it's ability to provide the most coherent information given the collector's mindset, while the preference for the later stems from it's ability to provide the maximum stimuli given the collector's mindset. the first functions as introverted by virtue of seeking the most coherent information (to compliment extroverted judging), the later functions as extroverted by virtue of seeking the maximum stimuli (to compliment introverted judging).
note: thinking about this in retrospect, the possible reason that Ne can appear to have a short-attention span for those who have a preference for coherence (Ni/Si), is because they see the Ne user changing what he/she is thinking about whenever expressing a new form, while the Ne user's brain is actually still breeding the same patterns, still focused on the same new genes and seen what new DNA they create.
it's an understandable confusion, though personally i find this confusion to be funny, since i was diagnosed with the exact opposite attention disorder (hyperfocus - the difficulty in shifting attention).