an empty witness stand

Tunnel Vision Memories

A recent study in Learning & Memory has some important implications for human factors practitioners. What they found probably won’t surprise you, but might not be something you have considered before.

Most theories of memory assume that representations are strengthened with repetition. We recently proposed Competitive Trace Theory, building on the hippocampus’ powerful capacity to orthogonalize inputs into distinct outputs.

We learned in our first human factors or psychology course that repetition increases the strength of a memory. But as always, the devil is in the details. Memorizing lists of random numbers or words is not what we do in real life. We are encoding much bigger and broader concepts or experiences. But the scope of these concepts and experiences is too much information to encode. So we focus on the most important parts. That makes sense as a strategy.

But when we are using repetition as our encoding strategy, repeating these important details over and over again, there is a catch. While those few important details get encoded very strongly and become long lasting and easily recalled, the rest gets lost. The memory ends up much narrower than we might like.

My Take

I can see a few critical flaws in this phenomenon that we need to be aware of. If we are designing systems that present information to users either as part of training or ongoing use, we need to recognize that details will be lost. Depending on the size of the concept, it could be MOST of the details that are lost. And then it gets worse. When users are recalling an experience, for example, their brains need to recreate a story around it. It is simply the way we are wired. So details get added. Just not necessarily the details that were really present during the initial encoding. And this happens under the surface, so users don’t even realize that some of the details they are remembering and that seem so real were added from our exemplar stereotype of the typical case.

Now imagine that the user is an eyewitness at a trial being cross examined by an attorney. The witness may legitimately recall the important factors that are relevant to the case. But the objective of the opposing attorney is to undermine the witness’ credibility. So all he has to do is ask about a few details, get the witness to remember something incorrectly for which there is some physical evidence, and point out the contradiction to the jury. They generalize this error and assume that all of the witness’ testimony is unreliable. Reasonable doubt established. Case closed.

Here is a more fun example. Imagine you are a parent and you are questioning your 7-year old daughter about the broken lamp. You are pretty sure she is lying about it and rather than just make the assumption and look like an unfair tyrant, you want to catch her in a clear fib. So you just ask about some details that she probably didn’t think much about. The story telling instinct jumps to the fore and something interesting, fanciful, and easily falsifiable comes out. Case closed. Manipulative perhaps, but effective.

Your Turn

I am really interested in your thoughts on this one. Do you have memorization strategies that give you a better trace of the details? We also learned in our first course that elaboration is better for encoding complex memories. But just how much elaboration can we expect from our users? Especially for details that might not seem relevant at the time.

Image credit: Brad Shorr

3 thoughts on “Tunnel Vision Memories”

  1. As far back as 1970, Andre Bisseret studied Air Traffic Controllers, and came up with some relevant observations. Controllers did not memorise data on individual aircraft, but their relative positions. If the aircraft were not involved in potential conflicts, they forgot them completely.

    Generally, people remember what they have learned they will need. U nfortunately, if they later need something they did not expect to need, it isn’t there.

    If you have taken a course on a piece of software – say, Excel – and do not use it for a few weeks, you will find it has gone completely when you need it.

  2. Mark, this is so timely. Did I hear someone say “Brian Williams?” I don’t have a personal strategy regarding this phenomenon, but when I conduct my classes or education sessions for clients, I ALWAYS try to link important info together into as big a picture (“story?”) as I can, so the participants have some context for what I am trying to teach. If they can grasp and retain the context, they’ll have a better chance to be able to properly apply ergonomics principles and approaches than if I simply walked them through using a tool like the NIOSH lifting equation or the Strain Index. I think this is more critical when we get to the topics of cognitive process, decision making and psychosocial/psychophysical issues.

    1. Brian Williams’ case is perhaps more complicated than just tunnel vision, but that is certainly part of it. He remembered the shooting and remembered the feeling of fear. It is natural to later associate those two and really feel like the shooting was at his chopper rather than the one in front.

      The other contributor in his case is reconsolidation – which I talk about a lot because it is really underemphasized in much of our work. Every time you recall a memory, your hippocampus is pulling it out of the prefrontal cortex. Then when you are done, it sort of sticks it back in, but skewed a little based on the current context. So every time Brian Williams told the story, more error was introduced. It is not surprising that he started out telling it correctly as the front chopper and later misremembered it as the one he was in. People point this out as evidence that he is consciously lying, but I suspect it is just the reverse.

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