Complex sentence: Why are humans often caught off guard by or slow to recognize the rare and novel, partly because built into the very nature of our experience is the propensity to extend existing knowledge and experience to future events and experiences.
Split into simpler sentences: Why are humans often caught off guard by or slow to recognize the rare and novel? Partly because built into the very nature of our experience is the propensity to extend existing knowledge and experience to future events and experiences.