Do you believe it's possible to actively control the way one perceives phenomena in the world? If so, do you think this is functionally related?
I ask this because I've had various experiences whereby I've been able to change the way I think about something, so that it enhances my actual experience. I'm also curious as to whether it would be related to a particular function.
It is entirely possible to actively control one's perceptions - I do it all the time. I believe that this falls within the remit of Ni, which is the perceiving function most concerned with perception itself.
Since you have Ni as your auxiliary function, it makes sense that you have had the experiences you describe. As an Ni-dominant, this sort of ability comes even more naturally to me, however it still qualifies as a skill which can be developed by learning and practising certain disciplines.
I recommend you to NLP (Neuro-Linguistic Programming), which has a vast range of effective tricks and tools for altering the way one perceives "reality". Here is a simple exercise, drawn from NLP, for changing one's mental state:
"Remember a time and place from your past when you were utterly at peace. Feel the contentment spread through your body, as you listen to the gentle sounds in the background and watch the tranquil scene before you. Close your eyes, breathe deeply and relax still further into the moment. You may notice the feeling of peace growing as you remember just how great it felt at the time and you may wonder to yourself just why you don't come back here more often and relive this wonderful experience"
Ok, I'm sure you get the point by now. This is a fairly unsubtle use of hypnotic language patterns to evoke a personal memory which will be unique to each person (There are no specific details whatsoever given in the exercise). However, done properly, it is guaranteed to alter one's mood (and therefore perceptions) to some degree, as memories of this type always have a somatic/emotional component, which can be reexperienced when the memory is fully invoked.