Lab 6: Measuring Intoxication

UW Biology of Addiction

Learning Targets for Lab 6

• To learn how intoxication is quantified and observed. • To learn how behavioral response is influenced by environmental

factors. • To understand specific types of intoxication, as well as symptoms. • To understand the difference between subjective judgment and

objective measurement.

Hypothesis/ClaimIF subject is tested with both subjective and objective methods of impairment judgement, objective measurements provide the best evidence of impairment.

Materials

• Vision Disc (HGN test)• Drunk goggles(Reaction Time)• Timer• Meter stick (Reaction Time)• Blue Tape Line• Stroop cards- Level 2 & 3• Walk and Turn Instructions• One Leg Stand Instructions

Model I

• http://www.youtube.com/watch?v=gu6UgQn_jFM

Q1: Was the subject intoxicated? What were the signs. What IS intoxication? A1: your response

Model IIIMPORTANT – read these instructions all the way through before we will proceed to the video.

• You will be asked to pause the video prior to its conclusion.

• This video takes you (rather a woman suspected of driving drunk) the three National Highway Transportation Safety Association’s (NHTSA) approved Field Sobriety tests.

• STOP the VIDEO @ 3:30 … she will be in the middle of the one-leg stand test. • http://www.youtube.com/watch?v=XqLeCZeKDj4

Q2 Would you pass or fail this woman? Support your answer.A2:

Model IIIhttp://www.dailymotion.com/video/x3t0ux_reaction-time_tech

Answer the following in your lab journal:Q3a– After watching this video consider what makes this experiment “scientific”. A3a:

Q3b – How might you modify the NHTSA tests to make them more “scientific”? A3b:

Q3c – What are some benefits to performing a more “scientific” experiment? I’m open-minded, what are some disadvantages to being “scientific” in this context? A3c:

Q3d- How does intoxication effect the response? (at the end of the lab)

PART I: FIELD SOBRIETY TESTS

For this the lab, you will work in pairs: One person is the subject, the other is the tester.

• You might want to switch notebooks with your partner. That way, the tester can record the subject’s data in her own notebook. • For each test there will be sufficient time for you to EACH have a

chance to be the subject.

A) Horizontal Gaze Nystagmus (HGN)

http://www.youtube.com/watch?v=YntJiBCz3pA&feature=related

The HGN is a test that examines a potentially intoxicated subject for his ability to smoothly track an object moving in his visual field. • An officer has the subject hold his head steady and follow

the movements of the object while the officer watches the subject’s eyes.

A) Horizontal Gaze Nystagmus (HGN)• The officer is looking for the position at

which the subject is unable to smoothly swing the angle of his eye to follow the object (nystagmus means eye jerk).

• Look at the diagram, noting the alignment of vision disc. • You can measure this angle by noting the

angle at which the eye twitch occurs as displayed by vision discs.

• Be sure to record your nystagmus angle in your journal. (Data Table coming up)

B) The one-leg-stand test (OLS)

Q4 – You’ve seen the one-leg stand test performed. Why would an intoxicated person perform poorly? Think of at least 3 reasons. A4:

• The instructions for this test are available ONLY for the person role-playing the officer. The subject must do as instructed by the “officer”. • Record your “grade” for the one-leg-stand in the space provided

C) Walk-and-turn test (WAT)

Again: only the OFFICER can see/read the instructions for the Walk-and-turn test

Answer the following questions in your lab journal• Q5a – In addition to your previous ideas, come up with one NEW

reason for failing this test. Is this test more or less difficult than the one-leg stand? • A5a:• Q5b – How might the officer who is performing the test influence the

outcome? • A5b-

• Be sure to record your score on the following data table

Data Table for Part I

Test Your Score Would you be under suspicion of DUI?

HGN

WAT /7

OLS /4

D) Other test we WON’T perform (“non-standard tests”)

Some states use other tests to measure sobriety, but these are poorly supported by scientific studies and are not supported by the NHTSA. • These include:• finger-to-nose test• counting test (counting backward by threes, for

instance)• Reciting the alphabet without singing or backwords

D) Other test we WON’T perform (“non-standard tests”) • The finger-to-nose test is a test for your sense

of proprioception. • Proprioception= your ability to determine

where your body parts are in space relative to the other parts.

• Not influenced by alcohol in the way that balance is• Does require cognitive processing in order to act

appropriately upon signals from the sensory cells

• Counting and alphabet tests are merely tests of computation, recitation and memory

D) Other test we WON’T perform (“non-standard tests”) Answer the following in your journal:Q6 – A counting and alphabet test can allow one to analyze cognitive functioning. Why are they not recommended tests? A6:

Q7 – Rethink your definition of “intoxication” (question 1). Do the tests you just completed test for ANY type of intoxication? A7:

Part II: Research Lab Tests for Intoxication

A) Testing and Modifying Reaction Time

• Subject sits on a chair and hold her fingers open around the base of a meter stick.• The tester will hold the top of the stick. • With no warning, the tester will release the meter stick. • When the subject notes its motion, s/he should grab it between the

thumb and finger of one hand. • Note the distance (IN METERS!) at which the thumb touches the stick.

A) Testing and Modifying Reaction Time

• Drunk Goggles are required for this part of the experiment! • Repeat this test 9 more times and place your data on the following chart.

Trial 1 2 3 4 5 6 7 8 9 10

Distance in meters

A) Testing and Modifying Reaction Time

• Now convert your data into reaction time (seconds) using the conversion in your lab packet. Record your reaction time (in seconds).

A) Testing and Modifying Reaction Time

• Q8: Why did we ask you to average trials 6-9 and ignore trials 1-5?A8:

• Q9a: How will distraction change the position on the meter stick that you catch at?

A9a:• Q9b:Will the distance on the meter stick increase or decrease?

A9b:• Q9c:Will the reaction TIME (units in seconds) increase or decrease?

A9b:

A) Testing and Modifying Reaction Time• Now test reaction time being

distracted… make it good… a real distraction…not just talking• Count backwards from 100• Speak in a foreign language• Alphabet in ASL• Are they ticklish? • Etc.

• Record your distance for 5 trials and compute your reaction time using these 5 trials. • Calculate your distracted

reaction time=_______s

Trial

1 2 3 4 5

m

B) Testing and Modifying Stroop Time

During each round of testing, the subject will have one job: to name the COLOR of the words that the tester points to… rather than reading the word.• The tester has two jobs in addition to pointing to objects.

1. Must record the time it takes the subject to complete the card 2. Must record the number of errors your subject makes. Errors?

B) Testing and Modifying Stroop Time

• Repeat each level as indicated by the data tables shown.

Level Time to complete

Errors

2

2

2

Average

Level Time to complete

Errors

3

3

3

Average

B) Testing and Modifying Stroop Time

• Level 2 is called “Congruent” • Level 3 is called “Incongruent” • Observe how much longer your solving time is when performing an

incongruent test as compared to a congruent test. • Compute your INCONGRUENT average – your congruent average =

________________

Model IV

• An “Expert Witness”, Dr. Greg Kane has a strong interest in the claims regarding the accuracy of field sobriety tests. • On his web site, he presents previously-

obtained data showing the correlation (or not) of the one-leg stand test vs. blood alcohol content (BAC).

• Q10: Is the OLS a GOOD test for intoxication? Why? Think like a defense attorney.• A10: