Complex sentence: Those with Asperger's syndrome also display a form of perseveration, in that they focus on one or a number of narrow interests, e.g. a person might go to a department store to incessantly look at air conditioners.
Split into simpler sentences: Those with Asperger's syndrome also display a form of perseveration in that they focus on one or a number of narrow interests. A person with Asperger's might go to a department store repeatedly to look at air conditioners.