Have you see Memento where Guy Pearce has difficulties creating new long-term memories? What that means is that he only has his short-term memory working for him. The film was praised by neuroscientists as an accurate portrayal of the different memory systems that we possess.

Types of memory

Types of memory

So What is Short-Term Memory?

Through attention, input from the senses is transferred to short-term memory. (See previous posts on sensory memory and overview of memory.) Think of short-term memory as a temporary holding place for your memories. How much of the sensory input goes into short-term memory depends on the attention we give it. Greater attention means more information moves to the short-term memory. And conversely, when we do not pay attention, we lose the sensory input forever. From the short-term memory, the processed inputs are moved to long-term storage.

But before we tackle long-term memory, let us understand short-term memory in greater detail.

Scientists tell us that short-term memory:

  • Holds limited information (7 ± 2)
  • Information is held for about 30 seconds to a minute. In that time, information must be transferred to long-term memory or processed in working memory
  • When new material comes in, previously held material is displaced or lost (unless it is stored in long-term memory)

The Seven Plus Or Minus Two Principle

George Miller, through his classic study in 1956, came up with the now famous principle that states that our short-term memory can hold 7 ± 2 items at a time. Did you know that US phone numbers were introduced in the beginning as having 7 digits based on this theory?

Here’s an interesting short-term memory test. Try it. What are your numbers like? I found out that remembering 7 items was no problem. Beyond that, I had to really work at it and try a few times. Does this mean George Miller was right? Are we limited to 7 or 9? Not really. We can employ some strategies to expand that number.

Strategies for Making Efficient Use of Short-Term memory

Chunking: Many of us at work or at home have a space crunch. How do maximize the usage of a tight space? Think of short-term memory in the same way. Proper organizing will ensure it can hold more information. Chunking is one such strategy which expands our ability to remember things in the short term by organizing the information into meaningful groups. e.g. Consider the number 568975638. Difficult to remember, isn’t it? Now try chunking it as 568-975-638. It is so much easier now. Some of you may chunk it slightly differently as some digits may be more meaningful to you. That brings us to the second strategy.

Association: Associating something meaningful to something that is not meaningful helps us to remember more. e.g. If my current phone number ended with 5638, then I would chunk the above number as 56-897-5638 and associate the last 4 digits with my phone number. This way, I only have to remember the first 5 digits plus the association. It is easier than having to remember 9 digits. Association is like storing similar items together in a tight space. You reduce the clutter and can store more as well.

Repetition: Most of us use this strategy when we have to make a call and have just read the number from a classified ad or website. This strategy reinforces or consolidates the memory through rehearsal.

Here’s a video-clip about a man with a 30-second memory


and here’s a TV version featuring Tom Hanks.


For further reading:

In the coming posts, I will explore long-term memory and how we can apply that knowledge to improving our own memory.

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