1. Should Lie detectors be used as evidence in British courts??
By the end of this lesson I will be able to:
Describe the responses the autonomic nervous system controls.
Explain the mechanism by which this happens.
Understand how we can measure changes in the autonomic nervous system.

3. Scenario
Body's response
Reason for response
How can response be measured?
Putting your hand on a very hot surface.
Running flat out for a mile.
Someone shouting BOO in the dark.
Telling a lie

4. Choose one of the scenarios you have just been looking at and explain it using the reflex arc.
Look at the methods that can be used to detect changes in the autonomic nervous system. Which method could be used to detect the changes that you wrote in your table.

5. Galvanic skin response
Someone shouting BOO in the dark.
Telling a lie.
ECG
Running flat out for a mile.
Someone shouting BOO in the dark.
Telling a lie.
EEG
Putting your hand on a very hot surface.
Someone shouting BOO in the dark.
Telling a lie.

6. Lie detectors as evidence?
The figures given for the accuracy of Polygraphs range from 70 to 90%.
Do the reactions that polygraphs measure only happen when a person is lying?
It is possible to fool a lie detector test. Also, many people who commit crimes believe their own ‘lies’.
Scientific studies produce much lower % accuracy than it’s supporters claim it has.
The results of a test are subjective and rely on the opinion of the ‘expert’ reading the test.
There are relatively few scientific studies into the effectiveness of polygraphs.