Ralph came home quite drunk from the party on saturday night. luckily, he was given a ride home. he threw his apartment keys down somewhere and immediately fell asleep. he may not be able to find his keys again until he is once again drunk because of:

This is because of " state-dependent memory". State-dependent memory refers to the phenomenon when someone recaptures his/her memories only when he is in that same state when that specific memory was formed. Usually the term is utilized when referring to a drug induced state of consciousness more particularly alcohol etc, but is implicated to other non drug induced states as well.