What is forensic psychology?
Forensic psychology is the combination of psychology and law. It is the
application of psychology in legal settings.
Forensic psychology, as defined by the American Psychological Association, is
the application of clinical specialties to the legal arena. This definition
emphasizes the application of clinical psychology to the forensic setting.
Christopher Cronin, who has written a well-known textbook on forensic
psychology, defines it as The application of clinical specialties to legal
institutions and people who come into contact with the law
Need For Forensic Psychological Tools
Forensic psychological tools include those instruments whose application can
result in detection of crimes. These tools can be utilised to recognize the
culprit from among the suspects as soon as possible.
Innocent persons can be prevented from being convicted falsely, which is a
serious issue since decades immemorial. Individuals committing serious offences
get away without getting convicted simply because of lack of evidence and it
encourages them to become recidivists.
As a result crime rate is on the increase. According to the National Crime
Records Bureau, the crime rate (crime incidence per 100,000 of population) in
India increased from 383.5 in 2018, 385.5 in 2019 to 487.8 in 2020.
Forensic Psychological Tools
Some of the prominent and most used forensic psychological tools in the process
of investigation are Polygraph, Behavioural Electrical Oscillations Signature
Profiling, Layered Voice Response, Eye Detect, Suspect Detection System etc.
Each one of these instruments are most of the time effective in detection of
culprits and can be used together to confirm detection if any doubt exists.
These instruments are a very useful aid in the investigation process.
Today when the crime rate is increasing more and more and with the advent of
technology in the commission of crimes such investigation techniques are a
How does the polygraph work?
The polygraph has 4 types of sensors. One is used for the recording of
respiration rate, another is used for the recording of the increase in blood
pressure, another one is used for detecting the oxygen consumption and last one
is used for detecting skin resistance. All these type of sensors are used for
the detection of culprits and innocents.
Brain Electrical Oscillation Signature Profiling
This instrument is used to detect whether an individual has any experiential
knowledge in the commission of crime. Only an individual who has committed a
crime will show experiential knowledge. This instrument is the most effective
and scientific one till date. Here the culprit can't manipulate anything.
Layered Voice Analysis
This machine detects changes in emotions in a person's voice, like, for example-
whether the person is under high stress or there is stress relief etc. It
detects those emotions in a person's voice that are below 10ms and that can't be
This instrument works by detecting changes in eye movement and other minute
changes such as pupil dilation and different types of eye expressions. This is a
new instrument used in crime investigation.
Suspect Detection System
This instrument uses Galvanic Skin Response as a sensor which is used to find
out changes in skin resistance under stressful conditions and this technique is
used for detection of criminals.
Use of these techniques have to be increased. Increasing use of these techniques
will lead to more detection, conviction and swiftness in solving a criminal
Written By: Sohini Basu
- Baran, Vogel, M. J. (2016). Inconclusive: The truth about lie detector
- Ginton, A. (2012). Estimated Accuracy Of CQT Polygraph Examination.
A Non-Standard Method for Estimating Accuracy of Lie Detection Techniques.