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Forgetting: Why and How We Forget

Can you remember the name of your first-grade teacher? Certainly, the information was stored at one time ― the teacher was a central figure in your life for nearly a year. If you can’t recall the name, is it still somewhere in your long-term memory?

Why we forget

Forgetting is simply the loss of information and is both necessary and useful. Imagine remembering every single second of every single day of your life. It would be very difficult to keep all the information organized and to focus on one thing at a time. There is just too much information to be remembered. We automatically forget most of the sensory information we take in without even realizing it.

The man who did not forget

There was a man who did not forget. Solomon Shereshevsky was a Russian journalist with a perfect memory. He never took notes during his interviews, but his articles were detailed and accurate. He told his editor that he didn’t need to take notes because he never forgot anything. His editor sent him to Aleksander Luria at a local university for testing.

Aleksander Luria

Over the course of the next 30 years, Luria would carry out an extensive series of experiments examining the journalist who would become his most famous case.

During the research trials, Shereshevsky was able to recall extensive lists of words, numbers, and even nonsense syllables without mistakes and with only occasional hesitation. He could also report the numbers or letters in reverse order. Not only this, he remembered them years afterward, as well as the clothes Luria had worn on the day he had first learned them!

Even events from early childhood could be recalled, including things that happened when he was still in his crib. There also appeared to be no limit to his digit span, as opposed to the seven to nine items that most humans can manage.

The ‘gift’ wasn’t a gift

Unfortunately, Shereshevsky’s gift was a serious handicap. He was unable to block unwanted memories. Also, he had a terrible memory for faces because he memorized them so exactly. People’s faces change with time, lighting, mood, and expression. Shereshevsky had difficulty recognizing faces because they looked so different to him from the ones he had completely memorized in the past.

Shereshevsky had trouble understanding abstract concepts or figurative language. Luria wrote about him: “He was not able to read poetry or fiction easily, as each word or phrase would blossom into an intense visualization that might be contradicted by the next one… Shereshevsky’s pathological memory interfered with his ability to hold a regular job, enjoy literature, or even seemingly to think in the abstract without being distracted by sensory association.”

Shereshevsky gave up his journalism career and became a professional mnemonist giving regular shows to paying audiences. Despite his success, he never had great satisfaction as a performer and gave it up after a while. He then became a taxi driver in Moscow but his life faded into obscurity afterward. Aside from a possible death date in 1958, there seems to be little else available.

How we forget

Many psychologists propose that long-term memory has almost limitless capacity and though we forget, it is not because the memory itself is gone. We just can no longer retrieve it.

The work of Wilder Penfield, a brain surgeon who used electrical stimulation to learn more about the function of parts of the human cortex, led scientists to suspect that some memories might be permanent and forgetting simply a failure in retrieval. (His main motivation was to perform needed brain surgery, and he was electrically stimulating the patient’s brain to make sure the operation would not destroy critical brain tissue.) Sometimes he would stimulate the patient in the frontal or temporal lobe, and the current would cause the patient to remember some event in vivid detail. During one operation, for example, the patient appeared to relive a long-forgotten childhood experience. During another, the patient heard Christmas songs in her church at home in Holland.

There are four basic theories about how we forget. It is most likely that all of these theories are partially correct:

  • Memory deterioration — memories fade naturally over time.
  • Memory distortion — memories are altered, distorted, or modified over time.
  • Retroactive inhibition — new memories interfere with/replace old memories.
  • Repression — memories are unconsciously blocked from our awareness.