Motor Errors: Actions Not As Planned

In all areas of cognitive activity, from memory to perception to language, errors can occur, and they are often quite revealing. The same is true in the realm of motor productions. Reason (1979) wrote:

In the same way that an adequate theory of language production must draw upon and account for slips of the tongue, so also must a theory of motor skills consider the apparently non-random lapses of attention and memory that appear so frequently among our daily actions. (p.68)

What are "actions not as planned"?

Reason called absent-minded motor errors Actions Not As Planned (ANAPs). He found that an ANAP commonly involved a goal-directed behavior with an improper element inserted into it or an action misdirected to the wrong goal.

How did Reason gather observational data in ANAPs?

Reason had 35 volunteers keep a diary of ANAPs over a 2-week period. He discovered several categories of errors.

1. The motor program runs normally, but the wrong variables are put into it. One object or stimulus is substituted for another. For example:

"I put shaving cream on my toothbrush."

What major categories of ANAPs did Reason uncover?

"I unwrapped a sweet, put the paper in my mouth and threw the sweet into the waste basket."

2. A person absent-mindedly switches from one program to another that shares the same starting pattern.

"I went up to my bedroom to change into something comfortable for the evening....The next thing I knew I was getting into my pajama trousers."

"I intended to drive to Place X, but then I 'woke up' to find that I was on the road to Place Y."

3. A person inserts, deletes, or changes the order of steps in a motor program.

"I came out of the sitting room in the daytime and flicked on the light as I left the room"

4. Elements of a plan, or whole plans, are forgotten.

"I intended to post a letter...but when I got home I found I still had the letter in my pocket."

"I went upstairs to the bedroom, but when I got there I couldn't remember what I came for."

What sorts of activities were almost always involved in ANAPs?

Reason points out that all these actions are "highly practiced and 'routinized' activities." Without conscious double-checking, we do not catch all the obvious errors. That is why, when people engage in procedures that are both routine and very important, such as preparing an airplane for flight, they must engage in conscious and systematic double-checking. Otherwise it would be too easy to get "absent-minded" after many repetitions and make a stupid, possibly fatal mistake. In common household activities, ANAPs are less serious. An occasional error like putting shaving cream on a toothbrush is harmless although it may leave a bad taste in one's mouth. Reason concluded that ANAPs were "the price of automatization."


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Copyright © 2007 Russ Dewey