Scientific research (Brenner & Zacks) observed that walking through doorways interferes with memory, facilitates forgetting. More specifically: the “doorway effect” is a theory based on the fact that retaining a memory is more difficult after literally walking through an actual doorway (to another room, the outside, the other lecture hall, in or out the church, a stage door). It appears that memory works better when remaining in the room in which it originally captured the information, and that one loses some of the information when walking out of the room - in real locations (like your practice room, the university, a museum, a shopping center, the green room) as well as in virtual reality simulations (like an Avatar program at DARPA; or Skyrim, the Sims, or Destiny on PSX). It’s called the “encoding specificity” principle and suggests that memory organizes information (amongst other things) ‘location based’ (exterior).
Research suggests that memory is optimized to keep information 'at hand' until its “shelf life” (statistical usefulness, need of projected accessibility) expires. This sort of memory representation has been called “event model” by Radvansky. In these cases the brain doesn’t store information in an organized retrieval structure (as that takes more calories). Imagine being in a subway station memorizing the number (and perhaps names) of stops to your destination, an opera house let’s say. After you passed through the sliding train doors and entered the portal of the opera house (a couple of doors really), most likely the brain estimated each time that the usefulness, shelf life, of the information has expired, been proven correct each time, and slowly diminished its recall-ability. It is apparent that a narrative is easier to remember than a shopping list for the untrained memory.
Master memory is cultivated by mnemonic training – the cultivation of a multi-layered and often emotionally connected retrieval structure. Soloists are capable of remembering a tremendous amount of information based on several, mostly inexplicable and un-researched, mnemonic applications. Concert pianists, for example, can perform a 45 minute piece with 30,000 individual notes, that have to be performed in an absolutely particular order, with rhythmical and dynamic variability, passionately creating an emotional and formal narrative, from memory, live on stage. And in Rach III they in addition coordinate with a large body of musicians, also from memory. The research on the doorway effect is quite insightful and relevant for the career musician (concert pianist for example) and the methodical pedagogue, and can be epitomized thus:
The stage and the practice room must become the same room.
As with all things of value, cultivation and constant practice is key. In order to keep all that has been achieved behind the practice room door, one should attempt to create a comfortable and familiar environment in the practice room, gain authority and mastery of the music and the instrument, and return to the same enjoyable and intimate environment on the stage. Imagine the door out of the practice room is the door onto the stage Matrix style. The concert performance is the tip of an iceberg - always keep that in mind and in sight.