Short-Term Memory Problems

  • Short-term memory problems are, by and large, attention problems.
  • Attention involves both the ability to keep focused on the information you want to keep active, and the ability to not be distracted by competing and irrelevant stimuli.
  • You need to actively attend to keep information active, particularly as you get older.
  • Many of us over-estimate how much information we can keep active at one time.

Many people, particularly as they get older, have concerns about short-term memory problems: going to another room to do something and then forgetting why you’re there; deciding to do something, becoming distracted by another task, and then forgetting the original intention; uncertainty about whether you have just performed a routine task; forgetting things you’ve said or done seconds after having said or done them; thinking of something you want to say during a conversation, then forgetting what it was by the time it’s your turn to speak, and so on.

This is clearly an issue for many of us. Part of the reason, I believe, is simply that we expect too much from ourselves. For example, research has shown that even a very, very short delay between recalling an intention and being able to carry it out is sufficient to dramatically reduce the likelihood that you will remember to do the intended action — we are talking about a delay of only 10 seconds!

The problem is exacerbated by age (I’m not talking about advanced age — I’m afraid certain aspects of cognitive processing begin to decline as early as the 30s).

Part of the problem is also that we tend to believe that we don’t need to do anything to maintain a thought, particularly when it has “popped” into our minds easily. But current estimates are that unrehearsed information lingers in working memory for less than two seconds!

Some of these problems are dealt with in my article on action slips (these problems are not, strictly speaking, a failure of memory, but a failure in attention), and in my e-book on Remembering intentions.

But in this article I want to talk about another aspect: the relationship between working memory, and attention (and, as it happens, intelligence!).

In my article on working memory and intelligence I talk about the difference between crystallized and fluid intelligence — that fluid intelligence is probably a better measure of what we think of as “intelligence”, and that working memory capacity is often used synonymously with fluid intelligence. A new theory is that the relationship between working memory and fluid intelligence is due to the ability to control attention.

This theory emphasizes the role of attention in keeping information active (i.e. in working memory), and argues that working memory capacity is not, as usually thought, about the number of items or amount of information that can be held at one time. Instead, it reflects the extent to which a person can control attention, particularly in situations where there is competing information / demands.

I have to say that this makes an awful lot of sense to me. I can’t, in the space I have here, go into all the evidence for and against the theory, but here’s one situation which is interesting. The “cocktail party phenomenon” is a well-known method in psychology, whereby people are given two streams of audio, one for each ear, and instructed to listen only to one. At some point, the person’s name is spoken into the unattended stream, and about a third of people pick that up. In a recent take of that classic study, researchers compared the performance of people as a function of their working memory capacity. Only 20% of those with a high capacity heard their name in the unattended channel compared to 65% of low-capacity people. The point being that a critical aspect of good attentional control is the ability to block our irrelevant information.

This ability is one that we already know is worsened by increasing age.

The message from all this, I guess, is that:

  • short-term memory problems are, by and large, attention problems.
  • attention involves both the ability to keep focused on the information you want to keep active, and the ability to not be distracted by competing and irrelevant stimuli.
  • you need to actively attend to keep information active, particularly as you get older.
  • many of us over-estimate how much information we can keep active at one time.

And if you want strategies to help you keep more information active, I suggest you look at improving your ability to chunk, condense and label information. If you can reduce a chunk of information to a single label quickly, all you need to do is remember the label. (I explain all this at length in my book The Memory Key, but I’m afraid it needs far too much explanation to go into here).

Anyway, I hope this helps those of you (most of us!) with short-term memory problems.

This article originally appeared in the April 2005 newsletter.


Heitz, R.P., Unsworth, N. & Engle, R.W. 2004. Working memory capacity, attention control, and fluid intelligence. In O. Wilhelm & R,W. Engle (eds.) Handbook of Understanding and Measuring Intelligence. London: Sage Publications.

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Action Slips

There is a very common form of forgetfulness that is not really a failure of memory. When we get in our car to drive to place A and find ourselves instead on the road to the more familiar place B, this is not a failure of memory. When we clear the table and find ourselves putting the margarine in the dishwasher or the dirty plate in the fridge, this is not a failure of memory. When we go into a room intending to do one thing and do something else instead, this is not, really, a failure of memory.

These are absentminded errors, and they happen to all of us. They have also been termed action slips, and this term is useful because it points more precisely to the nature of these errors. Let's look at the characteristics of action slips:

  • they usually occur during the performance of tasks that are so highly practised they are largely automatic
  • they usually occur when we are preoccupied or distracted
  • many involve intrusions of other habitual actions that share some characteristics with the intended action
  • such habit intrusions are more likely to occur when:
    • we're departing in some way from our usual routine (for example, you decide to stop adding milk and sugar to your coffee, then finding yourself doing it automatically)
    • the situation has changed, demanding a change in our usual routine (for example, a much-visited shop moves premises, but you keep going to its old location)
    • the situation shares features with a highly familiar situation (for example, you try and open a friend's car with your own car key)

Other types of action slips are:

  • place-losing errors - where you've lost your "place" in an action sequence, and so omit or repeat part of the sequence (for example, because of wheat sensitivities in my family, I make our own bread; accordingly, it is a highly practiced recipe, and I add all the ingredients in a fixed order. If something happens to distract me in the course of it, I may be unsure where I am in the sequence, and risk omitting or repeating an ingredient)
  • blends - where you get confused between two active tasks (for example, you write an email while thinking about the next email you're going to write, and address the current email to the correspondent for the second email)
  • reversals - where you get confused between parts of the same task (for example, you put an empty ice cube tray in the freezer, then turn to the tap to fill it)

You can see from all this that these everyday errors occur in the context of action sequences - that is, sequences of actions that we have practised so often they have become automatic. Dressing, undressing, washing, making coffee or tea, even making quite complicated recipes - these are all common examples of action sequences.

You can see why action slip is therefore a good name for these types of error.

Is there anything we can do to minimize action slips? Well, the standard advice is to pay attention to what you're doing, but of course the whole point of action sequences is that they free our mind from needing to pay attention, so this is not a strategy I particularly recommend. However, if there are some action slips that you are particularly prone to, you might want to try this.

The most useful thing you can do is simply be aware of the circumstances that set you up for such errors. Then you can either:

  • make a sterling effort to pay attention when it's important to you (for example, both my partner and I are careful when we are driving and need to depart from familiar routes, to remind ourselves - or each other - of our destination at key points), or
  • use an object to signal that you have done something, or remind you where you are in a sequence (to take the recipe example again, you could move used ingredients to a particular part of the kitchen bench), or
  • decide it's not important!

This article originally appeared in the December 2003 newsletter.


  1. Harris, J.E. & Morris, P.E. (eds.) 1984. Everyday memory, actions and absent-mindedness. Academic Press.
  2. Reason, J.T. & Mysielska, K. 1982. Absent-minded? The psychology of mental lapses and everyday errors. Englewood Cliffs, NJ.: Prentice-Hall.

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