Sound Adjacency

Lying in bed with eyes wide shut precisely at dawn, a sound intrudes that could be one of two things, equally: (1) a woodpecker working the very resonant trunk of a newly-dead tree; or (2) a cellphone ringtone, one of the simple ones that tries to mimic the ringtone of an actual telephone.  

Blind people must have to navigate such sound adjacency often.  With practice and a heightened focus, they get very good at it.  They seldom mistake the sound of a gentle summer rain for sustained applause, for example.