Crime costs the UK billions; cybercrime alone is estimated to cost £27 billion annually. ESRC-funded cognitive research has led to increased lie-detection rates during interrogation, up from 58 per cent in standard methods to 72 per cent using the new process.


  • Since 2003, Professor Aldert Vrij at the University of Portsmouth has delivered over 50 training sessions on the Cognitive Load (CL) technique to police, intelligence services, judges, legal professionals , bankers, psychiatrists, social workers and insurance agencies worldwide - including seven European countries, the US, New Zealand, Singapore and South Korea.
  • The CL technique has been incorporated into the training for US Federal Law Enforcement, which includes almost 70,000 personnel per year.
  • CL lie detection techniques are in use by intelligence organisations across a range of countries, including the UK, US, Australia, Israel and Singapore.
  • CL is an important aspect of training by New Intelligence, an Australian company that delivers interview training to Australian police and other major public sector agencies.
  • The company Innovation Group PLC implemented the CL lie detection approach to assess the validity of insurance claims during telephone interviews. As a result the percentage of claimants who decided to drop their claim rose to 65-72 per cent, compared to an industry average of 30 per cent.

About the research

Finding out when people lie during interrogation is vitally important in the context of security and counter-terrorism. Observing physical behaviour for signs of lying (such as being nervous) has proved to be largely unreliable, with merely 54 per cent accuracy – only slightly better than chance. Lying is, however, more mentally demanding than telling the truth; more thought is required to tell a lie and keep track of it than simply telling the truth. Building on original ESRC-funded research, Professor Vrij and other international experts have developed a 'Cognitive Load' (CL) technique that has a 72 per cent success rate in detecting when someone is lying.

Liars will have fewer cognitive resources available when the demands of the interview are increased. Cognitive demands can be increased by, for example, asking an interviewee to give an account in reverse order, asking unanticipated questions, requiring him or her to maintain eye contact with the interviewer, or simultaneously executing another task. Under these conditions liars show more signs of deceit and observers are better at detecting their lies. The CL technique has been adopted by police, military and intelligence agencies worldwide.