Psychopaths are better at learning how to lie than other people, scientists have found. Lying abilities improve rapidly among psychopathic individuals, and this is associated with changes in their brain activity.

The fact that people with high levels of psychopathy show greater tendencies to lie has already been well documented by numerous studies. Looking at their brain activity also indicated that they may be struggling to see the negative impact that their actions on other people and to acquire social moral norms.

Scientists thus wondered whether people with high psychopathic traits could have a natural capacity to lie better, hardwired in the brain, or if they are simply better than other individuals at learning how to lie quickly.

Lying based on photographs

To find out more, they conducted an experiment with university students, some of which exhibited high levels of psychopathic traits as assessed by the Psychopathic Personality Inventory, a personality test to detect psychopathic traits in adults.

In total, 52 students from the University of Hong Kong took part in the research, 23 of which showed low levels of psychopathic traits and 29 high levels of psychopathic traits. They took part in a task which involved looking at a series of photographs of familiar and unfamiliar faces. They received a cue to give either an honest or a dishonest response when asked whether they knew the person in the picture.

While they did that, the scientists observed their brain activity using fMRI and they also measured the time it took for the participants to give their response.

Participants did the task, then completed a training exercise before repeating the task again. The scientists observed that after completing the training, participants with high levels of psychopathic traits had significantly shorter response times when receiving the cue to lie, compared with the initial task. In contrast, individuals with low levels of psychopathic traits showed no changes in response time despite completing the training.

These findings suggest that psychopathic individuals are better at learning how to lie than non-psychopaths.

This may be an indication that the brains of individuals with high and low levels of psychopathic traits process lies in a different way - and indeed the scientists observed different patterns of brain activity which were consistent with this on the fMRI scans.

"During lying, the 'true' information needs to be suppressed and reversed. Thus, lying requires a series of processes in the brain including attention, working memory, inhibitory control and conflict resolution which we found to be reduced in individuals with high levels of psychopathic traits," lead author Tatia Lee said in a statement.

"By contrast, in individuals with low levels of psychopathic traits this lie-related brain activity increased. The additional 'effort' it took their brains to process untruthful responses may be one of the reasons why they didn't improve their lying speed."

The complete findings are published in the journal Translational Psychiatry.