After reading the chapter on this I decided to do some experiment's such as close my eyes and listen the sounds around me that I always in the past with look at for reference. One example was standing in the parking lot at work which has a lot of daily familiar sounds like trucks pulling in to front gate. I was surprised that I could map out where the trucks were and actually pinpoint their locations coming in and going to the loading dock approximately 100 yards in and to the left, I could even hear them swinging around and backing up to the loading dock. And also when I repeated this with my eyes open the were further away, out of danger than I thought. The book had mentioned this, that we tend to over-estimate on oncoming sound before it could become a danger to us. Attached is a link which delves into a lot of the survival responses that we deal with every day, I hope that you enjoy it.