We've all walked into a room only to find that the reason for doing so has suddenly and entirely vanished from our mind.
Psychologists have discovered the so-called ‘senior moments’ that can leave us utterly bemused and retracing our steps may actually be caused by the way the brain processes information as the body leaves one room and enters another.
http://www.dailymail.co.uk/sciencet...et-walked-room-Blame-door-say-scientists.html