Imagine you are one of our prehistoric ancestors wandering through the ancient forest when suddenly you hear a faint noise ahead. Is that the wind rustling believes or a dead branch falling off a tree, or is it a dangerous predator, perhaps a bear or tiger? Your answer could mean life or death.
If you assume the noise is a predator, but turns out to be just the wind, you have made what is called a Type I Error; that is, believing a pattern is real when it is not, in other words, a false positive. If you assume that the noise is just the wind, but it turns out to be a hungry tiger, you have made a Type II Error; that is believing a pattern is not real when it is, a false negative.
In making the Type I Error, you might be inconvenienced to varying degrees. On the other hand, if you make the Type II Error, you’re the tiger’s lunch. Obviously, the practice which permits the greatest level of survival, is to make the Type I Error. Whether this means that those who tend to make the type to error are eliminated from the gene pool by a biological evolutionary process, or their contemporaries learn from experience and pass this on to successive generations, matters not. The point is that we learn to recognize patterns, and the absence of complete information, assume the worst. We tend toward false positives. This is the survival mechanism at work, and it is found both in human beings, who are after all a species in the animal kingdom, as well as lower animals.
Fast-forward to the year 2013 late at night in one of our major cities. You’re walking on a lonely street in an area known for muggings and other criminal attacks, in which all the reported suspects are young males. Up ahead you see two young men. They are both dressed in what might be called gangsta-chic and seem to be hanging around with no apparent purpose.
What do you do? The alternatives are to assume the two men may be up to no good and look for an alternate route to where you are going, or give them the benefit of the doubt continue on walking up to them, hoping to pass by without incident. If you commit a Type I Error, you may be needlessly delayed in reaching your destination. On the other hand, if you commit a Type II Error, you could lose your wallet, and suffer a beating or worse. The answer is obvious, unless you are a fool.
Slight change of scenario. You are a police officer, sworn to protect and serve all persons in your city. Do you approach the two men and inquire as to who they are and what their purpose at the time might be? If you do, and based on your experience, you don’t get quite the right answers you frisk them for weapons, and perhaps check them out for outstanding warrants? Or do you just ignore them? If you commit either type error, you’re not doing your job.
That scenario can be changed up to the other end of a continuum, by changing the time of day, the location, and the appearance of the two men. The two men are in broad daylight, waiting at a taxi stand or bus stop, dressed in conventional suits and ties, carrying brief cases. Without more – a lot more – viewing them with suspicion would obviously be irrational. But I venture to say that scenario rarely occurs today.
Police officers, much more than ordinary citizens, have the training and experience to sort out ambiguities in marginal situations. They learn from street experience which patterns or situations are likely to be trouble, which are less so, and which are most likely to be harmless. This is the same learning process that makes a grand master quickly recognize a pattern on the chess board, or ordinary Americans to instantly recognize a word written in English in the Roman alphabet. Arabs likewise instantly recognize words in Arabic that look like doodling or chicken scratches to anyone other than a fluent reader of that language.
It takes a lot of experience. An article in Scientific American a while back opined that it takes about 10,000 hours, or five years of 40 hour work weeks to develop an “expert mind.” Significantly, 10,000 hours is the number of hours of flight time it takes to be hired as a commercial airline pilot. Most non-police officers do not develop the street sense facility. They have to rely on their common sense and general information and experience. This means they will make numerous Type One Errors – and will avoid harm in most cases.
Thus, profiling occurs all the time, and it will continue to occur. Insofar as considering a person’s race as a factor, in some situations it make sense – common sense. In other situations, it may not. Once thing is certain: The fact that someone being profiled is of a certain skin color should never be a reason to not inquire further when other factors are present. Even though that might lead to an accusation of “racial” profiling, it would be stupidity in the extreme. But then, what is often called “political correctness” is synonym for stupidity.