Two Problems with Long-Term Memory

Problem #1 with LTM--Encoding: Getting information into LTM

Examples of encoding problems:

    An extreme example of encoding problems--anterograde amnesia: a type of amnesia in which there is an inability to form new memories.
Some people with severe anterograde amnesia are unable to form any new semantic or episodic memories. As a result, they are stuck in the past.
Two well-known severe cases of total anterograde amnesia are

              The case of HM (as you watch that video, note the difference between STM and LTM).  If you want a more dramatic depiction of his case, click here.

              The case of Clive Wearing that we discussed in the section on episodic memory. If you saw that video but don't remember seeing it, you have probably experienced an encoding failure. Your encoding failure was probably due to not paying attention -- because unless you were black out drunk when you watched it, you are probably not experiencing anterograde amnesia.☺

Movies with relatively accurate depictions of the symptoms and effects of anterograde amnesia:


 Two less extreme examples of encoding problems from your experience that may show that you have failed to encode something you've seen numerous times:
  1. How many red stripes are on the American flag? How many white stripes? (You can check your answer by looking at this picture of an American flag)
  2. See the surprising thing that college students don't know about Apple
Information must be encoded into STM before it can be encoded into LTM

  As you learned when we discussed STM, you don't pay attention to most of the information your senses pick up, so most of that information doesn't get encoded into STM. If information doesn't get into STM, it won't get into LTM. Unfortunately, research suggests that most students do not get important lecture content into STM. Fortunately, as mentioned earlier, research also suggests that most students can easily increase their ability to attend to lectures (and thus get lecture information into STM so that it has a chance to get into LTM) by sitting up front and by keeping their cell phones out of sight. If you are paying attention but the information is coming too fast to keep it in your STM, you have two options: (1) you can improve your ability to chunk the lecture information by reading ahead or by being more mentally active during lectures (e.g., by getting more sleep, more caffeine, or more interest in the material)   or (2) you might ask the professor to slow down.

    *Besides not encoding information into STM, students may incorrectly encode information into STM. So, in addition to not hearing, students may mishear or misinterpret what is said. Sometimes, incorrect encoding is caused by "false friends": terms that sound like English words but have a different or more precise and technical meaning (e.g., statisticians use the words "random" and "significant" in ways that are very different from the way the average person uses those words).

Consolidation--Getting information from STM to LTM-- involves 2 steps: One mental, one physical

  But even if you pay attention to something and therefore encode that information into STM, you may not get that information into LTM. Getting the information from STM to LTM involves both your mind and your body. As you'll see, your mind will often have to do some mental work to encode information into LTM. After that, your brain will need some time to complete the encoding. In a sense, forming a solid memory is like making jell-o. To make jell-o, you do the work to assemble the ingredients, but the jell-o becomes solid only after setting in the refrigerator for a while. Similarly, to make a solid memory, your mind needs to do the work to integrate the information, but the memory becomes solid only after it has set in the brain for a while. The process of rewiring the brain to form a solid memory is called consolidation.  (An alcohol blackout--in which a person doesn't remember what happened while the person was drunk--is a case of alcohol disrupting consolidation, as is the inability of a concussion victim to remember what happened shortly before being hit in the head.) The need for consolidation has two implications for studying:

  1. Your memory will  benefit by taking a 15-minute break after learning information.
  2. Getting enough sleep is very important for consolidation and thus for being able to remember information.

Problem #2 with LTM--and the most serious problem with LTM --Retrieval: Getting information out of LTM.

Information is often available in long term memory (it is in the long term memory box), but not accessible (you can't get it out of the memory box at the moment you need it).

An extreme example of retrieval problems--some cases of retrograde amnesia: an inability, for a while, to retrieve what you once knew. Often, retrograde amnesia only affects episodic memory--it often only hurts the ability to remember some or all of one's personal past.  Retrograde amnesia is a key element in the plots of many soap operas and movies (e.g., "Overboard," "Bourne Identity," "Forgotten," "The Long Kiss Goodnight," "Regarding Henry," and "Who Am I?"). Real life examples of severe retrograde amnesia are rare, but here's one a short newspaper report of someone who had retrograde amnesia:  Missing Delaware woman turns up in Toronto homeless shelter.

Retrieval problems must be to blame in retrograde amnesia cases in which the memories eventually "return." Obviously, the memories did not "come back" in the sense that they left the person and then returned. Instead, the memories were there all along,  but the person could not retrieve them.  However, if the retrograde amnesia is permanent, the problem may not be a retrieval problem. In those cases, suspect that the "forgotten" memories no longer exist, especially if
  1. Retrograde amnesia is limited to failing to remember events that occurred shortly before a concussion or to events that occurred while drinking. In that case, suspect that the memory problem is due to disrupting consolidation (consolidation is the process of rewiring of the brain to form permanent memories). If consolidation was disrupted, the memories were never permanently stored.
  2. There is extensive brain damage due to injury or illness. Brain damage may completely destroy memories. See below for two such cases:

Below are some common examples of retrieval problems (examples of information being available [stored] but not accessible [retrievable]). Note that many of these examples involve being able to recognize the information but not being able to recall it:

If you can solve the encoding and retrieval problems, you can take advantage of LTM's virtually limitless storage capacity to do some amazing things--like this guy has done).

On to Solving Problem 1 of LTM (The encoding problem)

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