The W. Edwards Deming Institute Blog

Theory of Knowledge: Can We Trust Our Memories?

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Dr. Deming’s included the the theory of knowledge (how do we know that what we “know” is so) as one of the four inter-related components of his management system. How to apply an understanding of the theory of knowledge within the management system for their organization often gives people trouble. Lets look at how to shape a management system based on the science showing the frailness of our memories.

Trust your memory? Maybe you shouldn’t

People distort their own memories all the time — they remember getting better grades than they did, voting in more elections than they did, having kids that walked or talked earlier than they actually did

Russell Ackoff has a story* about this (I am basing this on my memory and probably not getting it exactly right). He would ask executives to write down there prediction and seal it and give it to him about sales or profit etc.. Then a few months later he would say he lost the predictions and ask them to write down what they predicted. Invariably they would remember that their predictions were much more accurate then they actually were.

His take from this was that they really believe that their prediction was more accurate than it was. And that makes sense to me based on my observation over the years (seeing people’s recall of predictions being quite different from what they said originally).

From this conclusion you can see opportunities to improve. First, people may well overestimate their ability to predict. They therefore may under-appreciate the problems due to poor prediction. They may also not see that their predictions are not very accurate and therefore should call into question the theories upon which those predictions are based.

Also this shows the importance of trying to cement the understanding of agreements. Sometimes people will think writing down what was decided in a meeting or in a discussion is not needed because we will remember. But memory is very malleable. What we remember about an event or decision changes over time. Writing down what was decided helps cope with the problem of relying on memory.


In my estimation, much of the frustration caused by people thinking others are not doing what they promised (and blaming the other person for intentionally not doing what was agreed to) is more likely due to the other person remembering things differently (and also often poor processes that result in failure to deliver, but that is a different topic). How you address a solution is different if you think it is intentional obstruction versus a process problem, in this case relying on memory which isn’t as robust a solution as documenting an agreement. When adding documentation the memory of the discussions still add understanding but the documentation provide an anchor that helps cope with our tendency to have our memories change.

Another way the Deming management system is designed based on the knowledge of the weakness of our memories is the focus on spotting special causes right away. An indication of a potential special cause is an indication to use special cause thinking. Special cause thinking is about figuring out what is special about the condition that caused this special result.

The process for figuring that out is too think about what is special now. If our memories were perfect we wouldn’t have so much trouble doing special cause analysis weeks or months later. But we do have great difficulty doing so. There are other reasons to act quickly: clues can be wiped out over time and special causes may continue to create problems until they are resolved (if they remain problems as a apposed to a passing issue that went away by itself).

Control charts are used by the people actually doing the work so that they get an immediate notification that they should start using special cause thinking. Some organizations mistakenly don’t have visual management for those doing the work to see an immediate indication of a possible special cause (which is due to them not understanding the management system and instead applying tools haphazardly). This creates a delay. Sometimes the delay is even more than a couple days – then people are asked to think about what was special several days ago; this is much less effective than if that question is asked immediately.

Related: The Neuroscience of DemingIllusion of Explanatory DepthNobody Gives a Hoot About Profit

* Someone told me page 130 of Creating the Corporate Future has what I am thinking of, but I don’t have the book with me and they don’t sell an electronic version (which would have immediate delivery by the nature of the wonderful logistics of ebooks, so I could check).


Categorised as: psychology, theory of knowledge


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