From “The Shallows: What the Internet Is Doing to Our Brains,” by Nicholas Carr.
When a person fails to consolidate a fact, an idea or an experience in long-term memory, he’s not ‘freeing up’ space in his brain for other functions. In contrast to working memory, with its constrained capacity, long-term memory expands and contracts with almost unlimited elasticity, thanks to the brain’s ability to grow and prune synaptic terminals and continually adjust the strength of synaptic connections.
‘Unlike a computer,’ writes Nelso Cowan, an expert on memory who teaches at the University of Missouri, ‘the normal human brain never reaches a point at which experiences can no longer be committed to memory; the brain cannot be full.’ Says Torkel Klingberg, ‘The amount of information that can be stored in long-term memory is virtually boundless.’
Evidence suggests, moreover, that as we build up our personal store of memories, our minds become sharper. The very act of remembering, explains clinical psychologist Sheila Crowell in The Neurobiology of Learning, appears to modify the brain in a way that can make it easier to learn ideas and skills in the future.