Apropos the OP's original query, ask yourself, no matter what time of day it might be when you sit down with your system to listen to something new/old/borrowed/blue; Do you find yourself listening with your eyes closed ... ?? Reading the preceding made me realise this is with the majority of people the default "listening" mode. Your 'wetware' is told to concentrate on one sense and automatically (temporarily) attenuates others, especially sight.
Listening in a darkened room or at night just helps this process. You're probably still sitting there at night, listening, with your eyes closed.