Hello doctors..how long it takes the brain to forget someone' face? thanks.

Memory: There is no way to predict or guarantee that any one memory will be forgotten or remembered. Memory does not work this way nor it is predictable in any given individual. The more one thinks about a memory, however, the more likely the memory will become permanent.

I'll get back to you: As soon as I forget the face of my favorite nursery school teacher from 1972, I'll post an update. The brain is an incredibly complex network. What one remembers & forgets depends on a large number of factors, not least of which are the degree of emotion associated with the memory, & the frequency of recollection. If you have lost a loved one, think of him/her, and your memories should last.