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What Is "Inattention?"

Marc Green

"[A typical accident report] attributes error to such things as 'lack of attention,' 'inattention,' 'failure of judgment,' or 'fatigue.' Explanations in terms such as these are, however, unsatisfactory because either they do no more than give a name to what has obviously occurred, or they suggest a cause without giving any insight into the way in which it might have operated to produce the accident in question." (Davis, 1959).

"So-called causes of accidents like recklessness and speeding are seen to be psychologically worthless, inasmuch as they are condemnations rather than explanations of the behavior in question."(Gibson, 1939).

Attorneys frequently use the word "inattention" when I testify. I try to avoid using this term because it is loaded and because it has two subtly different meanings that laypeople (and some "experts") readily confuse. Here, I cut through the confusion by explaining these two meanings and by explaining how they should and should not be used - if they are used at all.

1. Inattention as a restatement of events.

Suppose that a driver fails to see a pedestrian and strikes him with his vehicle. Someone will inevitably blame the driver on the grounds that he was "inattentive." Here's the logic used to reach this conclusion:

Question: Why did the driver fail to see the pedestrian?
Answer: Because the driver was inattentive.
Question: How do we know that the driver was inattentive?
Answer: Because the driver failed to see the pedestrian.

This is circular reasoning, a tautology as it is called in logic. It cannot be refuted because it uses "inattention" as a simple restatement of what happened. We already knew that the driver failed to see the pedestrian. In this sense, the concept of "inattention" is merely a shorthand label and adds nothing to an understanding of events. This is the sense that I use the term in several articles1.

2. Inattention as mental aberration

The second meaning of "inattention" refers to blameworthy behavior (or "negligence" as the courts would say.) In this case, the driver not only failed to notice the pedestrian, but he did so because he had some mental aberration (for lack of a better word) that put him outside the realm of reasonable prudence. Here, "inattention" is more than description; it is cause.

This is a different meaning from the first because people can fail to see but still be acting with reasonable prudence. If the driver says that he didn't see the pedestrian before hitting him, then he obviously was "inattentive" in the first sense, but not necessarily in the second. Humans have constraints on their behavior. Just as the human body's physical construction limits the weight that can be lifted, the mind's construction limits our ability to attend. Moreover, "inattention" is not an aberration but rather the norm. The senses receive far more information that our minds could possibly handle, so we are all inattentive to most of the world at any moment. People need good reason to direct attention to some place or to some object so that it is seen.

The question that a human factors expert must decide is whether the causes of this failure to see ("inattention" in the first sense) can be explained by the normal workings of human senses, and cognition given the circumstances. If so, the driver acted normally, and the accident was not caused by mental aberration ("inattention" in the second sense). A person can act reasonably and intelligently and still have an accident because the circumstances violate expectation, have some other peculiarity or are poorly designed.

Now, suppose that after looking at the facts, I cannot explain the driver's behavior in terms of the normal limitations/predispositions imposed by the human mind. I would conclude that the driver had not acted reasonably. At that point, I might be tempted to say that the driver caused the accident through "inattention." Here, I would be using "inattention" as a shorthand for saying that I cannot find any "normal" reason for the failure to see2. As Davis suggests, however, the term "inattention" by itself still offers no insight concerning the actual cause.

However, I often try to avoid using "attention" in the second sense because it is so easily confused with the first. An attorney might ask me whether the driver was inattentive. If he failed to see the pedestrian, then I would have to answer "yes," at least in the first sense. But I might have concluded that the answer is "no" in the second. If the attorney wants to blame the driver, then he can choose to interpret my answer in the second, causal sense.

In sum, the term "inattention" has two meanings, one a description of an accident and a second a causal factor of the accident. A person can be described as being "inattentive" in the first sense but not in the second or may be accurately described as inattentive in both. Because this is all fairly confusing, it is better to avoid the concept altogether. If the driver failed to see the pedestrian, there is nothing gained by calling it "inattention." If the driver's behavior cannot be explained by normal human limitations and predispositions in the circumstances, then I say that he did not act in a way that I would expect from a reasonably prudent person.


Davis, D., (1959). Human Errors and Transport Accidents, Ergonomics, 2, 24-33.

Gibson, J. J. (1939). Review of "Psychology and the Motorist". The Journal of Abnormal and Social Psychology, 34(1), 143-144.


1"E. g., Inattentional Blindness," Occupational Health & Safety Canada, pp. 23-29, Jan/Feb 2002.; "Accidents, 'Inattentional Blindness' And Human Nature," Claims People, pp 6-7, Vol. 12 first Quarter, 2002; "Why Do Humans Cause So Many Accidents?" Without Prejudice (Journal of the Ontario Insurance Adjusters Association), pp 44-48, May, 2003; "Nursing Error and Human Nature," Journal of Nursing Law, in press 2004.

2Of course, there may clear reasons that the driver was "inattentive." He may have been texting a message, for example. In this case, the accident occurred because he was looking away from the road. It is better to explain human action in terms of actual, observable behavior than in terms of a hypothetical mental aberration. Often, however, the reason for the "inattention" (as a mental defect) is not obvious, so it is simply a default "explanation" when no good reason for the failure to see is apparent. Without a specific behavioral cause, the term "inattention" is worthless. It is an admission that the cause of the accident is unknown.

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