Tuesday, October 23, 2012

Brain Rule #5: Repeat to remember

My summaries of the book Brain Rules continue...
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Chapter 5: Short Term Memory
In the late 1800s, Hermann Ebbinghaus did a groundbreaking study on memory, and we regularly mention some of his conclusions still today.  Medina gives us one of the most famous: "People usually forget 90 percent of what they learn in a class within 30 days" (100).  Ebbinghaus' conclusion was that different memories have different life spans.  The more a person repeats the memory to oneself, especially at intervals apart from each other, the more likely it is to stick long term. "Spaced learning is greatly superior to massed learning."

Backing up a little, there is more than one type of learning.  "Declarative memories are those that can be experienced in our conscious awareness" (101).  The names of the planets or what color shirt someone was wearing are these kinds of memories.  By contrast, nondeclarative memories are memories of which we are not consciously aware, like the motor skills that enable us to ride a bike.

Declarative memories involve four steps: 1) encoding the memory, 2) storing it, 3) retrieving it, and 4) forgetting it (98).  Chapter 5 is about the process of encoding memories. The most famous example of this process not working is a person known as H.M. He suffered a head injury that caused him serious seizures, and a neurosurgeon removed part of his temporal lobe (behind his ears) in the early 1950s. The result is that he was not able to convert short term to long term memory. Many years later, he could not recognize himself in the mirror, because his long term memory only remembered his face from his late 20s.

Interestingly, when your brain gets new input, it breaks it apart and distributes it to different storage places in your brain.  "It is like a blender left running with the lid off" (104).  For example, vowels and consonants go to different places, as one woman who suffered a particular stroke experienced (105).  The question of how the brain keeps such distributed information together is called the "binding problem."

For our experiences, the encoding is automatic.  Other memories, like memorizing a Social Security number, require "effortful processing" (107).  There are three other kinds of encoding.  Semantic encoding has to do with the meanings of words. Phonemic encoding has to do with sounds and structural encoding has to do with shapes.

The big question, again, is how the brain keeps track of the different pieces of a memory in the different parts of the brain. Despite our ignorance of the answer, Medina gives three key observations. First, "the more elaborately we encode information at the moment of learning, the stronger the memory" (110).  The more connections we make to a memory, the more likely we are to remember it, especially if we make a personal connection to it.  "More complexity means greater learning" (111).

Secondly, "A memory trace appears to be stored in the same parts of the brain that perceived and processed the initial input" (111). "The neural pathways initially recruited to process new information end up becoming the permanent pathways the brain reuses to store the information" (112).  "The brain has no central happy hunting ground where memories go to be infinitely retrieved." Instead, memories are stored in multiple areas.

Finally, "Retrieval may best be improved by replicating the conditions surrounding the initial encoding" (113). Where were you when you learned something?  What mood were you in at the time? You've probably heard to retrace your steps when you can't find something.  It's a sound suggestion.

Medina ends the chapter with three suggestions to improve your encoding of memories.  They all boil down to what Medina calls "door handles." The more associations, the more handles you have on the door to the memory, the more likely you are to be able to remember it.

So, first, give real world examples (114-15).  The more examples, the more likely you are to remember.  The more personal an example, the more likely you are to remember. The more you connect new information to information already stored in your brain, the better you'll remember.

Secondly, give compelling introductions when you are speaking (116-17).  "Introductions are everything." "The events that happen the first time you are exposed to a given information stream play a disproportionately greater role in your ability to accurately retrieve it at a later date."

Finally, associating learning with a particular environment can enhance the encoding. The example was given of a family that was trying to teach its children both English and Spanish at home.  The breakthrough came when they designated one room in the house as the "Spanish room" where only Spanish was spoken. The familiar setting helped the family encode Spanish memories in that room.

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