As the name suggests, lie detection is a method of getting to know the truth with the help of certain techniques. In this process, technological gadgets may be used so as to record the physiological functions of the liar. The technological gadgets used in this process are assessed afterwards in order to determine the truth or deception by observing and analyzing the response given by the person being detected. Mostly, such lie detection tests are used by the law in some severe cases of crime or where the person being prosecuted is difficult to handle so as to ascertain truth. Lie detection is also called as deception detection. There are numbers of options available in the relevant field for lie detection. Let us have a look at some of the commonly used options for lie detection.

Inquiring and testing on general basis

In this option or technique for lie detection, different types of questions are asked from the person under prosecution. In this person, irrelevant questions, comparison questions and relevant questions are asked to determine if the person being enquired is telling truth or just pretending. Additionally, there may be some advanced type of questions too in the lie detection test. These are Control questions or guilty knowledge questions.

Polygraph test

In this process, autonomic reactions or changes taking place in the guilty person are taken into consideration. It is because such changes or reactions are out of control of the conscious mind and are triggered due to instantaneous stimulus. The major physical changes that are taken into consideration are blood pressure, heart rate, skin conductivity, rate of respiration, muscular movement, capillary dilation etc. To record these physical changes, different types of testing machines are used on the concerned person.

Event-related potentials

Also known as ERP in short, event related potentials test is based on evaluation of the acknowledgement using P3 amplitude waves. The results of this test are based on the fact that the P3 amplitude waves are larger in case an item is acknowledged. In simple words, this test is based on simple rapid perceptual processes. 

Electroencephalography

This type of test is commonly called as EEG and is chiefly meant to evaluate brain activity with the help of electrodes that are attached to the scalp of the person being prosecuted. In this process, the person under assessment is made to recognize some consequential data. For this, certain objects or pictures are shown to the person and questioning techniques are also used along with to detect the lie.

Silent Talker Lie Detection

It involves detecting the truthfulness or deception of the guilty person by recording and assessing his/her nonverbal behaviour. In this process, various mircoexpressions of the concerned person are monitored over time slots. The expressions thus recorded are then encoded so as to distinguish them into true or false behaviour.

These are some of the commonly used options for lie detection. There are many more techniques that are used as per circumstances and conditions. The main aim of all these tests is to get to know the truth and detect deception.