Q. Why does a memory come seemingly out of nowhere?
A. This kind of involuntary recall usually involves words, phrases or names, rather than events. Generally, there does not seem to be any immediate trigger or reminder.
The phenomenon was given a name, mind-popping, by one of the few researchers to study it, George Mandler, a pioneer in memory research who died in 2016.
He and his colleagues found that such a memory usually occurred during a task that was relatively automatic, such as routine grooming or housekeeping, which left the mind free to wander.
They speculated that the recall might involve what is called long-term priming, information related to the memory that was acquired days or even weeks earlier than the actual recollection.