Professor Howard Eichenbaum explains that encoding and retrieving memories are distinct neurobiological processes.
Encoding and retrieval are fundamentally separate stages that we have in the processes of memory. So during encoding, we’re acquiring information. That’s a perceptually driven process in which we acquire information and form representations that are embodied in the activity of neurons in the brain. During retrieval, somehow we have to reactivate those neural representations, which we believe then reactivates our conscious awareness of what it was we’ve seen before and we retrieve information.