Human Memory:How it works?

[Slav Defence]

1. How a memory is made

Let's say you meet someone new. The first time you see her, you take it all in: the length of her hair, the sound of her voice, that fresh shampoo scent that follows her around. As you're fumbling for an opening line, your hippocampus, a sea-horse-shaped area in your brain's temporal lobe, has already converted all these external stimuli into a memory. All potential memories must go through this mental gatekeeper before they take root in your mind. But the hippocampus is just a holding area, the first step in a complex process. After a memory has been forged, it's disassembled into its various sensory components, which are then distributed throughout the brain. Later, when you think of the person or happen to hear her name, see her face, or smell her hair, the components are drawn together again.

2. How alcohol affects your memory

Before it hits you over the head with a hangover, too much booze produces temporary amnesia by interfering with the ability of the hippocampus to create memories. (This is also known as a "blackout.") The memories that aren't lost can be especially tough to recall—unless you start drinking again and your brain taps into something called "state-dependent" memory. "When you encode memories while in a specific state, like being drunk, you're more likely to remember them when you're again in that state," says Jonathan Schooler, Ph.D., an assistant professor of psychology at the University of British Columbia. This may explain why Old School quotes start flying faster right around last call.

3. Why you can't remember being born

You might think something as traumatic as birth would leave its mark on your memory, but chances are you can only recall back to age 5. Why? One theory points to myelin, the protective nerve sheathing that helps with signal conduction; before age 5, a child's brain is low in myelin. "It may be important in long-term memory maintenance," says Schooler. Another possible explanation: As we learn to speak, we can no longer access memories created in our preverbal years. "With the onset of language, the way we think may change, making it impossible to get into the shoes of our older memories," Schooler says.