It's just one of the fascinating peeks into the mystery of the human mind chronicled on "Memory Hackers," airing Wednesday at 9 p.m. on PBS' "Nova."

"Memory is an inherently interesting thing," the show's writer, director and producer, Michael Bicks, tells The Post. "You think you know what it is, but when you think about it, you realize that you don't."

Many of us assume that memory is like a faithful recording of our lives stored in our brains, persistent and unchanging.

Shockingly, that's not the case. Researchers have discovered that memory is changeable. The act of recalling something alters it.