Short-Term Memory
Think of your memory bank as a board, the information to be stored in your memory as nails to be driven into the board, and your attention as the hammer to be used to drive the nails into the board. If your attention is compromise many of those nails will not be hammered in correctly, if at all. The nails will fall out; likewise, the information will fall out and not be stored in your memory.
Ed Hallowell
Herman Ebbinghaus, a German psychologist born in 1850, is most famous for discovering the most depressing fact in education. People usually forget 90% of what they learn in class within 30 days. Also, the majority of forgetting occurs within the first few hours after class.
Ebbinghaus pioneered the experimental study of memory and performed the first real science-based inquiry into human learning. He is known for his discovery of the forgetting curve and was the first person to describe the learning curve. Both have been confirmed many times since.
Herman Ebbinghaus and the Forgetting Curve
Why is memory so important?
Memory makes us human, it makes us who we are, and shapes our knowledge. It records every emotional and intellectual act and our great joy or terrible misery. It determines who you are, what you can do, and how you see your world. Every mental operation you perform depends on easy access of information you acquired earlier in your life. You find an experience meaningful because of its relationship to what is already in your mind.
Memory is essential to our existence, and for that reason, our brains have remarkably powerful capacities for memories. In the words of John Gabriele, Professor at MIT, that “in reality, memories are actually used for the future. It’s the way we learn about the world so that we’re more competent, more skilled, and more efficient the next time we encounter a task. And so, while memory is of the past, it is an essential tool of the future.”
Reflecting on memory, William Falkner said, “Memory believes before knowing remembers.” He is expressing something that is intuitive; that learning and memory are intertwined, i.e., learning is the process whereby new information about the world is acquired, and memory is the process whereby we hold that information over time.
Quoting Eric Kandel, who was awarded the Nobel Prize in Physiology or Medicine in 2000 for his research on the physiological basis of memory storage in neurons: “Learning is the means whereby we acquire new working knowledge about the world. Memory is the means whereby we retain that knowledge over time. Our ability to learn and remember is essential to our sense of self and our ability to function effectively in daily life. Memory is the glue that holds our mental life together. As a result, we are who we are in large part because of what we have learned and what we remember from experience.”
The idea of memory was well known to the ancient Greeks. The word memory is derived from the ancient Greek myth of Mnemosyne, the Greek goddess of memory, who was “said to know everything, past, present, and future.” Mnemosyne was the daughter of Uranus & Gaia, and was the mother of the Muses. According to Greek mythology, Mnemosyne slept with Zeus on nine consecutive nights, and after each night, she gave birth to a child, and each offspring was one of the nine Muses (poetry, the arts, etc.), each related to imagination.
Humans have MANY memory systems with numerous overlapping names and functions: short-term memory/working memory, long-term memory, explicit/declarative memory, semantic memory, procedure memory, sensory, prospective memory, and so forth.
John Medina, author of Brain Rules, talks about memory
http://brainrules.net/short-term-memory
Short-term or working memory
Working memory was a pioneering concept introduced by leading neuroscientists like Alan Baddeley and Patricia Goldman-Rakic, but it has since undergone many alterations.
Psychologists and researchers now believe that short-term memory is a collection of temporary memory capacities, each capacity specializes in processing a specific type of information, and each operates in parallel fashion with the others. As a result of this theory, short-term memory is now called working memory to reflect this multifaceted talent.
Working memory is a busy, temporary workplace; a desktop the brain uses to process newly acquired information. It is the type of memory that enables you to spit back the last sentence of a conversation and is critical for performing some common operations in your head: adding numbers, composing a sentence, following directions, etc.
Much of the time, we need to store information only briefly—while dialing a phone number or reading a paragraph from beginning to end. The brain accomplishes this with short-term memory, which holds data for seconds to several minutes.
Brain Break
1. People usually forget what percentage of what they learn in class within 30 days?
2. The idea of memory was well known to the ancient Romans. True or False
3. Psychologists and researchers now believe that what type of memory is a collection of temporary memory capacities?
Answers: 1. 90%, 2. False-Greeks, 3. Short-term
But there are limitations with short-term memory. First, it can only hold about four unfamiliar items at a time and eight items if they are relatively familiar (capacity).
Second, information is quickly lost from short-term memory (duration). Researchers have established that short-term memory data is lost in approximately five to twenty seconds unless immediately acted upon.
Let’s examine these two phenomena since they directly affect memory and the retention of new information.
George A. Miller: The Magical Number Seven, Plus or Minus Two
First example of the phenomena of capacity & duration; the time newly acquired information spends in working memory before it disappears. The Magical Number Seven, Plus or Minus Two theory explains memory duration while giving some sense as to why there are three groups of digits in a phone number, notes on a scale, or days in a week.
George A. Miller, one of the founders of cognitive psychology and a leader in the study of short-term memory, while working at Bell Laboratories, published a paper in Psychological Review that remains one of the most frequently cited papers in the history of psychology. In his 1956 paper, “The Magical Number Seven, Plus or Minus Two,” Miller proposed that short-term memory is subject to certain limits, including span and the quantity of information that can be stored at a given time.
With his opening sentence, “My problem, ladies and gentleman, is that I have been persecuted by an integer,” Miller suggests there is a fixed capacity for humans to receive information. Miller’s hypothesis is that given random list of letters, words, numbers, or almost any kind of meaningful familiar item, seven (plus or minus two) items was the magic number that characterized people’s memory performance.
Modern estimates of the capacity of short-term memory are lower, typically 4-5 items. Beyond this capacity, new information can “bump” out other items from short-term memory and become extinct which is one form of forgetting. In order for information to be remembered, maintenance rehearsal -re-exposure to the information – must occur.
For instance, if someone speaks to you before you’re able to dial a telephone number, you will probably forget the number. This interaction destroys mental rehearsal. To retain phone a number, the information must undergo maintenance rehearsal before the interruption.
To test yourself, try the following memory-span test. Spend about 7 seconds memorizing the following list of 7 digits: 7 4 3 8 5 9 2. When you have finished, look away and try repeating them in order. If your memory span is average, you probably had no difficulty recalling all of them.
Now do the same thing with the following list of 10 digits, giving yourself 10 seconds to memorize them: 6 7 9 4 5 8 1 3 2 9. Unless you have an unusual memory, you probably did not do as well on the second list.
Noteworthy for educators of children younger than 15, in her book, Brain Matters: Translating Research into Classroom Practices, Patricia Wolfe notes that studies have shown that the number of items that can be held in working memory varies with age. At age 5, a child can recall only two digits, plus or minus 2, if asked to recall a string of digits like the one above. At age 7, a child can recall an average of three, plus or minus two, and at age 11, the average recall is five digits. The number of digits a child can recall accurately increases by one every two years until a mental age of 15. At this age, the normal adult capacity of seven (plus or minus two) is reached (Pascual-Leone, 1970).
The 18-Second Holding Pattern
The second example of the phenomena of capacity and duration; the 18-Second Holding Pattern. The 18-Second Holding Pattern states that without rehearsal and constant attention, information remains in the working memory for only about 15-20 seconds (McGee & Wilson, 1984) before it disappears (becomes extinct) and forgotten.
The first study of the 18-Second Holding Pattern was carried out in 1959 by Peterson and Peterson (Gazzaniga et al., 1998). They gave subjects the task of remembering a set of three consonants, such as SVL or XCL, that had been flashed on a screen for a fraction of a second. As soon as the letters were removed, they instructed the subjects to count backwards by three in time with a metronome. At three seconds, approximately 20% of the subjects had forgotten the consonants, and at 18 seconds, no one could remember them.
Patricia Wolfe points out that “fifteen to twenty seconds may seem to be so brief a memory span as to be almost useless, but a closer look suggests this is efficient. It would be a disadvantage to remember permanently every word in every sentence you have ever read. A memory system that provides temporary storage of just the right amount of information without overloading itself is indeed efficient.”
In short, there are limitations of time and capacity that affect the duration of newly acquired information in working memory. In order to increase the durability of information and decrease the possibility of forgetting, active responding or doing something with the 7±2 items within approximately 18-seconds is required.
To test your short-term memory, take any of the three test below.
The famous "Stroop Effect" is named after J. Ridley Stroop who discovered this strange phenomenon in the 1930s.
The Stroop Test. https://www.youtube.com/watch?v=sLAp3PMDIQY
The n-back test is a good test of short-term memory. https://www.psytoolkit.org/experiment-library/nback.html
As a result of his research, Kandel concluded that “short-term memory had been linked to functional changes in existing synapses, while long-term memory was associated with a change in the number of synaptic connections.”
Finally, to fully understand the neuroscience behind short-term memory, a short examination of the biochemical side of memory is necessary. In fact, the 2000 Nobel Prize in Physiology or Medicine was awarded to the scientist who conducted the research.
It is widely accepted that the brain changes when you learn. This is what happens in the dendrites of neurons when they encounter a learning experience. This is the physical part of your memory, the hard drive of your memory. Learning causes a physical change in your brain. Every time you learn something new, you physically change your brain. This is called neuroplasticity.
In his research with sea slugs, Eric Kandel discovered that memory is a chemical process involving proteins/amino acids and there are differences in the processes between short- and long-term memories.
Click here for an interview with Eric Kandel.
In 1983, the Kandel lab took on the task of identifying proteins that had to be synthesized in order to convert short-term memories into long-lasting memories. Kandel, in collaboration with David Glanzman and Craig Bailey, discovered that when the number of dendrite spines increased, the size of the spines increased. They also identified a protein as being involved in long-term memory storage and as a result of its activation, there is an increase in the number of synaptic connections.
As a result of his research, Kandel concluded that “short-term memory had been linked to functional changes in existing synapses, while long-term memory was associated with a change in the number of synaptic connections.”