I'm not sure the name for it but I have heard it said that when faced with uncomfortable silence our minds will make up for that. It happened a great deal to me in my childhood. My mother would later comment on my asking about non-existent noise I would 'hear' at bedtime. To this day, as I go to bed or lie awake in the middle of the night my mind wanders and settles upon noise - real or imagined. I am not concerned about it.