Research into the 2011 London riots found they were mostly committed by antisocial persons, less than 20% of whom were explicitly gang members. This is because gang membership is primarily for the most antisocial of such persons . New research has identified extreme antisocial personality as a key reason why some criminals join gangs. Even within criminals, some find it harder to get along with others, and the most antisocial, being socially excluded, seek out others as a way of fitting in and making friends with people like themselves. These persons form gangs.

Persons with an antisocial personality often act rashly and don't think or care how their behaviour might harm others. As a result, they become excluded from school and work, others tend to avoid them because they make for disagreeable and difficult company. They struggle to make friends and end up feeling isolated and rejected until they meet peers of a similar character.

The researchers believe that some people seek out because they are looking for other people like them, with whom they share similar personality and values. Joining a gang may be their only way such persons can make friends, fit in, and feel as if they belong.

The findings contradict previous theories that gang membership is driven by fear, intimidation or , for which the evidence is often more anecdotal.

The study, conducted by Dr Vincent Egan of the University of Leicester's School of Psychology, and Matthew Beadman of UCL (University College London), London's programme, has been published in the journal .

The researchers approached adult male prisoners to take part in the study, and gave them a range of psychometric . They also asked about and feelings of commitment to different . They found that even within a group of prisoners, 'antisocial personality' emerged as a strong indicator of involvement in gangs.

Antisocial personality is characterised by impulsivity, low self-discipline, low self-control, and a lack of concern for other people's problems. Researchers also found that those with an felt little connection to peers who might be a good influence. They preferred more antisocial peers who reaffirm their values and attitudes.

Within a large group of prisoners (all of whom are 'antisocial') the most antisocial were more involved in more crimes, and more likely to be in a gang. Despite being present, the emotional and social feelings in adult offenders were not related to the number of crimes they have committed, nor gang membership. This result may be different in younger offenders.

The results suggest people stay in gangs because they make friends with other members and feel a strong connection to the group. In a gang impulsive and antisocial behaviour is praised and respected, rather than being seen as disruptive, further increasing the feeling of belonging.

Dr Egan of the University of Leicester's School of Psychology said:

"Our findings suggest individuals with low agreeableness seek out similar peers (in terms of disposition and attitudes) and this assortative process drives gang membership rather than socialisation alone.

"Anti-social group formation is strengthened if low-agreeableness individuals are rejected from prosocial peer groups, and peer group rejection predicts gang membership and deviance…

"Our findings suggest interventions seeking to reduce gang adherence focus on antisocial rather than emotional thoughts and behaviours, reiterating the importance of offence-focussedinterventions."

More information: Egan, V. & Beadman, M. (2011). Personality and gang embeddedness. Personality and Individual Differences, 51, 748 - 753. dx.doi.org/10.1016/j.paid.2011.06.021

Journal information: Personality and Individual Differences