Brain Rules by Dr. John Medina Brain Rule # 6 (part 2)– Long-Term Memory – Repeat to Remember

In the previous rule, Medina presented Short-Term Memory and in the beginning of rule 6 he explained Working Memory, now he begins discussing Long-Term Memory. Up to this point, memory is short lived. However, understanding how to get something into our long-term memory remains very useful.

Next, our long-term memories are consolidated with other memories by current stimuli. For instance, a childhood memory of a German shepherd dog may be stimulated by watching a documentary about a dog of the same kind. Without the stimulus to remember, that childhood memory would remain dormant. Therefore, the ability to retrieve memories gains importance. “…our retrieval systems are powerful enough to alter our conceptions of the past while offering nothing substantial to replace them. Exactly how that happens is an important but missing piece of the puzzle.” (p. 127)

Two models of long-term memory have emerged: 1) memory passively imagines libraries; and 2) memory aggressively imagines crime scenes. (p. 127) Both of these models are correct. Early on our memory is like a library, but as time goes by it is more like a detective’s search. Sometimes a long-term-memory can be distorted as the detective fills in the missing pieces in an attempt to come up with the complete story.

Knowing that our memories can be inaccurate, it behooves us to provide our brains with repetition. “The typical human brain can hold approximately seven pieces of information for less than 30 seconds. If something does not happen in the short stretch of time, the information becomes lost.” (p. 130)

Three ways to reinforce memory:

  1. Space Out the Input – the left inferior pre-frontal cortex is stimulated when one is retrieving a memory. (p. 132-133) According to the neurodevelopmental approach, we encourage short, frequent input.
  2. Sparking Interest – As in a romance or what we often call falling in love, “long-term potentiation” is the idea that increasingly limited exposure can result in increasingly stronger responses. (p. 133-136) Neurodevelopmentalists recommend “intense” or “focused” input as a part of learning.
  3. Steps in Long-Term Memory

1)      “Sensory information comes into the hippocampus from the cortex, and memories form in the cortex by way of the reverse connections.”

2)      “Long after the initial stimulus has exited the hippocampus and the relevant cortical neurons are still yapping (communicating) about it.”

3)      “While these regions are actively engaged, any memory they mediate is labile and subject to amendment. But it doesn’t stay that way.”

4)      “After an elapsed period of time, the hippocampus will let go fo the cortex, effectively terminating the relationship. This will leave only the cortex holding the memory of the event.” P. 137-138

Finally, the last step is “forgetting.” “Forgetting allows us to prioritize events. Those events that are irrelevant to our survival will take up wasteful cognitive space if we assign them the same priority as events critical to our survival.’ (p. 143)

Medina summarizes Rule 6 with the following statements:

1)      “Most memories disappear within minutes, but those that survive the fragile period strengthen with time.”

2)      “Long-term memories are formed in a two-way conversation between the hippocampus and the cortex, until the hippocampus breaks the connections and the memory is fixed in the cortex – which can take years.”

3)      “Our brains give us only an approximate view of reality, because they mix new knowledge with past memories and store them together as one.”

4)      “The way to make long-term memory reliable is to incorporate new information gradually and repeat it in time intervals.” P. 147

With this, Medina completes his discussion of memory. As time goes on, we begin to understand more and more about how we are “fearfully and wonderfully made”, and yet we must be reminded that our understanding is still very limited because the Psalmist asks “who can know it?” (Psalm 139).

Brain Rules by Dr. John Medina Brain Rule # 6 Repeat to Remember –(part 1 Working Memory)

 

Medina continues his treatise on memory in this new, but identical rule – repeat to remember. Old metaphors do not describe well what we now understand as the process of memory. Short-term memory is much more active than previously thought.

“Working memory is now known to be a busy, temporary workspace, a desktop the brain uses to process newly acquired information.” P.124

According to Alan Baddeley, British scientist, there are three or four components of working memory:

1) Retention of some auditory information – phonological loop;

2) Retention of some visual information – images and spatial;

3) Central executive – keeping track of all activities throughout this three part process.

4) Episodic buffer (later added; not as widely accepted or developed) any story a person may hear– with limited capacity and duration.

Medina illustrates working memory with the great chess champion, Miguel Najdorf, who played 45 chess games simultaneously within 11 hours – winning 39; tied 4 and lost 2 all while blindfolded. His opponents had to verbally announce their moves and thus he was able to visualize each game in his working memory.

At this point in Rule 6, Medina begins to describe long-term memory which we will discuss next time.

Brain Rules Dr. John Medina Brain Rule # 5 –Short-Term Memory – Repeat to Remember

Medina begins this chapter relating the story of a man named Kim Peek who was born in 1951. They labeled him as mentally disabled and recommended that his parents institutionalize him. Instead his father nurtured him and helped him develop great intellectual strengths. While born with an enlarged brain, no corpus callosum and a damaged cerebellum, he didn’t learn to walk until he was 4 years old. However, he could read, understand and remember two pages at a time. Someone who interviewed him in a library found that he knew everything about every book in that library. He wrote a screen play that became the movie, Rain Man.

According to Medina, memory comes in four steps: encoding, storage, retrieval and forgetting. This chapter is about the first moments of encoding. Some scientists believe that it is our memory that makes us consciously aware. ‘”Encoding describes what happens at the initial moment of learning, that fleeting golden instant when the brain first encounters a new piece of declarative information.” P. 103 “To encode information means to convert data into, well, a code.” P. 106 There are three kinds of encoding – semantic; phonemic and structural as demonstrated in the following test. Read word in capital letters and then answer the question:

1)FOOTBALL

Does this word fit into the sentence, ‘I turned around to fight ______?’

2) LEVEL

Does this word rhyme with evil?______

3) MINIMUM

Are there any circles in these letters? ______ p. 107

As scientists have worked on cracking the code, they have come up with three common characteristics of the encoding process:

1)      “The more elaborately we encode information at the moment of learning, the stronger the memory.” P. 110 OR if you attach a meaning to the information you learn, the easier to remember.

2)      “A memory trace appears to be stored in the same parts of the brain that perceived and processed the initial input.” p, 111

3)      “Retrieval may best be improved by replicating the conditions surrounding the initial encoding.” P. 113
Medina continues exploring memory in the next rule regarding Long-Term Memory.