The Finger Dexterity Test

The Finger Dexterity Test, “Damn, Your Drunk Tests Are Hard.”

In the movie, The Man With Two Brains, Steve Martin’s character is subject to ridiculous roadside sobriety tests. Some of the tests to which Ohio drivers are subjected are also suspect.  One such test is the Finger Dexterity test.

The Finger Dexterity test is not a Standard Field Sobriety Test. It has not been recognized by the National Highway Traffic Safety Administration. It is arbitrary and of little value. However, this test is a favorite amongst Ohio law enforcement officers.  Try the test yourself. I have administered this test on countless individuals that have consumed zero intoxicants and most fail.

This is how the Finger Dexterity test is conducted:

1. The suspect must select which hand they will use for the test;
2. Then, the suspect is instructed to touch the thumb of the selected hand and touch each finger tip starting with the index finger and moving toward the pinky finger;
3. Next, the suspect must count out loud each time their thumb touches a finger (i.e. “1, 2, 3, 4”);
4. As soon as the suspect touches the pinky and counts out loud the number 4 the suspect must immediately execute the test in reverse;
5. The suspect’s thumb must touch the pinky finger tip a second time and work backward to the index finger;
6. Then, the suspect must count backward, “4, 3, 2, 1”;
7. The suspect must perform this routine 3 times.

That Sounds Easy, Right?

The police officer wants to see if you do the following:

1. Cannot count in sequential order properly;
2. The suspect does not strike the thumb tip with to the tip of the target finger.

The contact area of the thumb tip and the finger tip is subjective. Furthermore, the officer is not on camera when conducting this test. No one can question his or her observations. When you couple that with the problem of confirmation bias (the officer is looking for evidence of intoxication), your chance of “passing” this test in the eyes of a police officer investigating you for DUI and samll.

While not part of the three-test Standardized Field Sobriety Test battery, the Finger Dexterity test is prescribed by officer training as a tool to be used to determine if the officer is justified in continuing the detention of the driver.  If reasonable articulable suspicion of impairment is shown, the officer is justified in asking the driver to exit the car to take standardized tests. The test is not scientifically validated to demonstrate impairment, but Ohio police officers use it anyway.  The non-standardized tests are allowed into evidence despite their lack of correlation to impairment.

Below is an example of the Finger Dexterity test. Demonstrate the test to your friends and co-workers to see if you can spot signs of intoxication.