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Interesting topic, this.
But seriously, I think one way of looking at it is that our minds are basically pattern matching algorithms. We look for patterns in our daily lives that "interest" us, either because it is our job to be interested in them (e.g. a policeman who spots what he thinks is suspicious behaviour), or because they have to do with our hobbies or our political views or whatever. We sift through the barrage of stimuli that inundates us every second of our lives, searching for the bits that are somehow relevant to us. And when we somehow notice patterns that correspond to what is interesting to us, then it attracts our attention.
Not sure if this is of any help, but maybe it's a place to start.