In the human brain, information must be stored in order for learning to take place. So, the areas of the brain that are most important to learning are those involved in memory. Other crucial areas include regions involved in processing information from the five senses and information about your body. They serve as the input to the memory system. Cognitive psychologists sort memory into three categories: short-term memory, routine-based memory and memory of events and facts.
Working memory, also sometimes called "short-term memory," is located in the frontal lobe, an area of the brain sitting behind the forehead at the front of each cerebral hemisphere. Working memory is a capacity for temporarily storing and manipulating information needed to carry out cognitive tasks such as learning, reasoning and understanding. It is involved in processing, storing, and retrieving data from long-term memory.
In a famous article called "The Magical Number Seven, Plus or Minus Two," George Miller, a psychology professor at Princeton University, found that working memory can store up to nine items for a short amount of time. An item is a chunk of information; for example, a digit you "carry over" in subtraction.
Researchers now believe that the capacity of working memory is more limited. Psychology professor Jeff Rouder from the University of Missouri and his colleague Nelson Cowan found that the average person can keep only three or four items in his working memory at any one time. People with high-capacity working memory rely on "chunking," a process that groups items together. For example, if you are familiar with Internet jargon, you may be able to hold the 8-letter sequence "XOLOLSYS" in your head by dividing it into the three items "XO," "LOL" and "SYS".
Declarative memory is an umbrella term for episodic memory, which is memory of events, and semantic memory, which is memory of rules and fact-based information. Declarative memory is processed and stored in different areas of the brain's limbic and cortical systems.
A study conducted by neurobiologists Emily Malin and James McGaugh at the Center for the Neurobiology of Learning and Memory at University of California, Irvine, showed that a single memory is processed in three separate areas of the brain. The hippocampus, a part of the limbic system located in the basal medial part of the temporal lobe, is responsible for processing memory for context. The anterior cingulate cortex, a part of the cerebral cortex connected with the prefrontal cortex, is involved in retaining unpleasant memories. Finally, the amygdala, an almond-shaped subcortical region in the medial temporal lobe, binds memories together and initiates the storage of both contextual and unpleasant information.
The significance of the amygdala in memory storage is a newer finding. Psychology professor Michael Gabriel from the University of Illinois Beckman Institute for Advanced Science and Technology and Amy Poremba of the National Institute of Mental Health in Bethesda simultaneously tracked neuron activity in several regions of the brains of rabbits whose amygdala had been temporarily disabled. Unlike the rabbits with unaltered brains, rabbits with a disabled amygdala were unable to learn to distinguish tones that lead to a mild shock from those that did not. The study shows that the amygdala sorts experiences worth storing from those that are not on the basis of emotional significance.
Procedural memory is routine-based "how-to" memory, as in memory of how to ride a bike or tie your shoes. This kind of memory is likely located in the cerebellum, or little brain, a separate structure underneath the cerebral hemispheres and attached to the bottom of the brain.
The cerebellum may also be the site for our creative language capacity. Researchers used to think that memory of how to form grammatically correct sentences was part of declarative memory. But a study conducted by psychology professor Victor S. Ferreira from University of California, San Diego, and his team showed that amnesiacs, who have impairments to declarative memory but no impairments to procedural memory, had a remarkable creative language capacity. The finding suggests that our language skills may be a kind of "know-how" rather than a sophisticated cognitive skill.
- Science Daily: Psychologists Demonstrate Simplicity Of Working Memory
- Science Daily: Researchers Prove A Single Memory Is Processed In Three Separate Parts Of The Brain
- Science Daily: Area Of Brain Found To Play Key Role In Initiating Memory Storage
- Scientific American: How Does the Brain Form Sentences?